Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Marteloscopen – studiemateriaal voor de praktijk
    Ouden, J. den - \ 2016
    Vakblad Natuur Bos Landschap 13 (2016)121. - ISSN 1572-7610 - p. 28 - 29.
    bosbeheer - dunnen - proefvelden - bossen - experimentele bossen - bosbouwkundige handelingen - forest administration - thinning - experimental plots - forests - experimental forests - forestry practices
    De afgelopen jaren zijn op diverse plekken in Nederland bossen ingericht als marteloscoop. De naam “marteloscoop” is afgeleid van het Franse martelage = hameren of blessen, en –scoop = kijken, onderzoeken. De marteloscoop “Oostereng” is officieel in gebruik genomen tijdens de jubileumbijeenkomst van Pro Silva Nederland op 8 oktober 2015. Het betreft een 0.5 ha grote douglasopstand uit 1961, waar in totaal 12 groepen een dunning hebben gesimuleerd. De algemene dunningsinstructie luidde: “Zet een dunning uit waarmee de houtteeltkundige waarde van de opstand zoveel mogelijk verhoogd wordt.”
    Reshaping institutions : bricolage processes in smallholder forestry in the Amazon
    Koning, J. de - \ 2011
    Wageningen University. Promotor(en): Bas Arts, co-promotor(en): Freerk Wiersum. - [S.l. : S.n. - ISBN 9789085856979 - 268
    tropische bossen - bolivia - amazonia - governance - bosbezit - bosbouwkundige handelingen - besluitvorming - plattelandsgemeenschappen - niet-gouvernementele organisaties - instellingen - bosbeleid - tropical forests - bolivia - amazonia - governance - forest ownership - forestry practices - decision making - rural communities - non-governmental organizations - institutions - forest policy
    This thesis aims at identifying the different kinds of institutional influences on forest practices of small farmers in the Amazon region of Ecuador and Bolivia and how small farmers respond to them. It departs from the perspective that institutions affecting forest practices are subject to processes of institutional bricolage in which small farmers construct their own institutional frameworks by aggregating, altering, or articulating elements of existing disparate institutions. This research demonstrates that institutions, whether introduced by government, NGO, or already existing, are subject to processes of institutional bricolage that can be either conscious and strategic of nature or less conscious and unintentional.
    Zelfregulerende bossen; een modelstudie naar effecten van "niets doen" en actief beheer op ontwikkelingen in bosstructuur
    Schelhaas, M.J. ; Wijdeven, S.M.J. ; Werf, B.W. van der - \ 2005
    Wageningen : Alterra (Alterra-rapport 1270) - 43
    bosbedrijfsvoering - bosbouwkundige handelingen - houtteelt - biodiversiteit - opstandsontwikkeling - opstandsstructuur - bossen - modellen - forest management - forestry practices - silviculture - biodiversity - stand development - stand structure - forests - models
    In deze modelstudie worden de effecten van `niets doen¿ en actief beheer onderzocht op de bosontwikkeling en structuurvariatie. Hiervoor is een model verder ontwikkeld en zijn koppelingen gelegd met monitoringsdatabestanden en analyse- en visualisatietechnieken. Simulatieresultaten dienen voorzichtig geïnterpreteerd te worden door beperkingen in het model. Enkele mogelijke hypotheses die uit de simulaties naar voren komen zijn onder ander dat de variatie fluctueert in de tijd, dat op middellange termijn er een grotere structuurvariatie tot stand komt bij beheer dan bij `niets doen¿ en dat bijvoorbeeld het effect van storm de verschillende beheerscenario¿s kan overtreffen
    Gezond werk in het groen; onderzoek naar de inzet van cliënten uit de zorg bij het beheer van bos, natuur en landschap
    Oosterbaan, A. ; Blitterswijk, H. van; Vries, S. de - \ 2005
    Wageningen : Alterra (Alterra-rapport 1253) - 41
    geestelijke gezondheid - geestelijke stoornissen - psychiatrische voorzieningen - natuurbescherming - gezondheidszorg - vegetatiebeheer - bosbouwkundige handelingen - organisaties - druggebruikers - nederland - arbeid (werk) - sociale zorg - mental health - mental disorders - psychiatric services - nature conservation - health care - vegetation management - forestry practices - organizations - drug users - netherlands - labour - social care
    In 2005 is een inventariserend onderzoek uitgevoerd naar de inzet van cliënten uit de zorg bij bos-, natuur- en landschapsbeheerorganisaties. In vrijwel alle regio’s van de grote beheerorganisaties worden op de een of andere wijze mensen met gezondheids- of andere problemen ingezet bij werkzaamheden in natuur en landschap. De meeste regio’s geven aantallen van 1-10 per jaar aan, maar bijna een kwart 30-100. Geschat wordt dat de genoemde beheerorganisaties gezamenlijk 1500-2000 mensen met gezondheidsproblemen laten werken in het groen. Hierbij gaat het vrijwel altijd om uitvoerend buitenwerk (bomen zagen, opsnoeien, knotten e.d.). De belangrijkste groepen zijn psychiatrische patiënten, (ex)verslaafden en verstandelijk gehandicapten. Voor de beheerorganisaties spelen ideële overwegingen een belangrijke rol. De begeleiding van de cliënten en ook de financiering van het werk varieert: soms door de natuur-, bos- of landschap¬organisatie, soms door de gezondheidsorganisatie, soms gecombineerd. Veel genoemde factoren, die pleiten voor werken in bos, natuur en landschap zijn het buiten zijn, de buitenlucht, werken in de natuur en fysieke inspanning. Naar de werkelijke effecten is meer onderzoek gewenst
    Houtkwaliteit en bosbeheer; beslist meer aandacht waard (deel 1)
    Wijers, R. ; Oosterbaan, A. - \ 2005
    Vakblad Natuur Bos Landschap 2 (2005)8. - ISSN 1572-7610 - p. 12 - 15.
    bosbeheer - houteigenschappen - bosbouwkundige handelingen - hout - kwaliteit - forestry practices - forest administration - wood properties - wood - quality
    Dit artikel gaat in op verschillende aspecten van houtkwaliteit in relatie tot het gevoerde bosbeheer. Het omvat de gehele inlandse bosbouw en houtverwerkingsketen
    Wanneer is goed veilig?
    Niemeijer, C.M. ; Oosterbaan, A. - \ 2004
    Vakblad Natuur Bos Landschap 1 (2004)6. - ISSN 1572-7610 - p. 26 - 27.
    bosbouw - bosbomen - bosbouwkundige handelingen - onderhoud - gereedschappen - openbaar groen - bosopstanden - forestry - forest trees - forestry practices - maintenance - tools - public green areas - forest stands
    In de jaren negentig bleek de bosbouw- en groenvoorzieningsector een van de onveiligste sectoren te zijn in Nederland. Verbetering van de werkomstandigheden was dus hard nodig. Hierbij is de beschikbaarheid van goedgekeurde apparatuur en middelen een belangrijk aandachtspunt. Logo's (als kwaliteitsaanduiding) kunnen de aspirant-koper helpen om iets goeds te kopen
    Bedrijfsdiagnose bosbedrijven; een methode voor bedrijfsonderzoek
    Raffe, J.K. van; Jong, J.J. de; Wolf, R.J.A.M. ; Schrijver, R.A.M. - \ 2002
    Wageningen : Alterra (Alterra-rapport 440) - 137
    bosbouw - ondernemingen - bosbedrijfsvoering - operationeel onderzoek - kosten-batenanalyse - bosbouweconomie - bosbouwkundige handelingen - nederland - bedrijfseconomie - forestry - enterprises - forest management - operations research - cost benefit analysis - forest economics - forestry practices - netherlands
    In dit rapport wordt een methode van bedrijfsonderzoek beschreven waarmee het bedrijfsmatig handelen van bosbedrijven kan worden vastgesteld. Op basis van de methode is een computerprogramma (een prototype) gemaakt dat in de praktijk is getoetst. Met de methode en de software moeten boseigenaren gestimuleerd en ondersteund worden tot een meer bedrijfsmatige manier van werken.
    Bedrijfsdiagnose bosbedrijven; een methode voor bedrijfsonderzoek
    Jong, J.J. de; Raffe, J.K. van - \ 2001
    Wageningen : Alterra (Alterra-rapport 247) - 83
    bosbouw - ondernemingen - bosbedrijfsvoering - operationeel onderzoek - kosten-batenanalyse - bosbouweconomie - bosbouwkundige handelingen - nederland - forestry - enterprises - forest management - operations research - cost benefit analysis - forest economics - forestry practices - netherlands
    In dit rapport wordt een methode van bedrijfsonderzoek beschreven waarmee het bedrijfsmatig handelen van bosbedrijven kan worden geanalyseerd. Dit rapport moet de basis zijn voor een computerprogramma dat bosbedrijven en hun adviseurs kunnen gebruiken. Achterliggend doel is bosbedrijven een hulpmiddel te bieden waarmee ze gestimuleerd worden tot een meer bedrijfsmatige manier van werken.
    Uitwerking bedrijfsplanning geïntegreerd bosbeheer voor gemeente Someren; deel 5 werkplan 2000
    Raffe, J.K. van; Wolf, R.J.A.M. - \ 2000
    Wageningen : Alterra (Alterra-rapport 52.5) - 39
    bosbedrijfsvoering - doelstellingenmanagement - planning - bosbouw - bosbouwkundige handelingen - economie - natuurbescherming - nederland - experimentele bossen - bedrijfsinformatiesystemen - geïntegreerd bosbeheer - forest management - management by objectives - planning - forestry - forestry practices - economics - nature conservation - netherlands - experimental forests - management information systems - integrated forest management
    In het voorbeeldbedrijf Someren wordt getoond hoe bos beheerd kan worden volgens de principes van geontegreerd bosbeheer. Daarbij wordt ook veel aandacht besteed aan de bedrijfsvoering die samengaat met de toepassing van geontegreerd bosbeheer. Voor dit doel is een aantal voorbeeldplannen opgesteld (beheervisie, beheerplan en werkplan). Deze plannen, die zijn opgesteld op basis van een door Alterra ontwikkelde planningssystematiek, zijn in dit rapport samengebracht.
    Over planning bij geïntegreerd bosbeheer; naar aanleiding van een workshop op de manifestatie Bos & Bomen 2000
    Wolf, R.J.A.M. ; Raffe, J.K. van - \ 2000
    Nederlands Bosbouwtijdschrift 72 (2000)4. - ISSN 0028-2057 - p. 129 - 132.
    bosbeheer - bosbedrijfsvoering - bosbouw - bedrijfsvoering - doelstellingenmanagement - natuurbescherming - bosbouwkundige handelingen - bosinventarisaties - experimentele bossen - noord-brabant - geïntegreerd bosbeheer - forest administration - forest management - forestry - management - management by objectives - nature conservation - forestry practices - forest inventories - experimental forests - noord-brabant - integrated forest management
    Door Alterra en Eelerwoude Ingenieursbureau is een planningsmethodiek opgesteld voor geïntegreerd bosbeheer en uitgewerkt voor de gemeente Someren (Noord-Brabant). Een aantal aspecten worden besproken: schaal (planningseenheden); zoneren (natuur, houtproductie, recreatie); doelformulering (terreindoelen); maatregelcriteria (voor het uitvoeren van beheersmaatregelen); bosinventarisatie (moment, soort inventarisatie, inventarisatie-eenheid); relatie beheersplanning en Programma Beheer
    Behoud van structuurvariatie en menging in het Zeisterbosch; Pro Silva excursie oktober 1999
    Wolf, R.J.A.M. ; Houtzagers, M.R. - \ 2000
    Nederlands Bosbouwtijdschrift 72 (2000)1. - ISSN 0028-2057 - p. 13 - 15.
    bosbedrijfsvoering - bosbouwkundige handelingen - bosbouw - gemeenschapsbosbouw - houtteelt - houtteeltkundige systemen - bossen - mengsels - opstandsontwikkeling - opstandskenmerken - opstandsstructuur - variatie - ruimtelijke variatie - verjonging - natuurlijke verjonging - bosopstanden - gemengde opstanden - natuurlijke opstanden - utrecht - forest management - forestry practices - forestry - community forestry - silviculture - silvicultural systems - forests - mixtures - stand development - stand characteristics - stand structure - variation - spatial variation - regeneration - natural regeneration - forest stands - mixed stands - natural stands - utrecht
    Hoe behoud je structuurvariatie en menging door kleinschalige ingrepen en natuurlijke verjonging in een oud en zeer gevarieerd bos. Verschillende soorten opstanden in het Zeisterbosch werden bezocht en bediscussieerd
    Modellering van bosbeheer in SUMO
    Wamelink, G.W.W. ; Wegman, R. ; Slim, P.A. ; Dobben, H.F. van - \ 2000
    Wageningen : Alterra (Alterra-rapport 66)
    bosbedrijfsvoering - bosbouwkundige handelingen - biomassa - bossen - velling - dunnen - struiken - simulatie - modellen - nederland - onderlaag - forest management - forestry practices - biomass - forests - felling - thinning - shrubs - simulation - models - netherlands - understorey
    In het vegetatievoorspellingsmodel SUMO is de beheermodule uitgebreid met twee vormen van bosbeheer: regulier bosbeheer en hakhoutbeheer. Het regulier bosbeheer bestaat uit elke vijf jaar dunnen en kaalkap aan het eind van de omloopperiode. De omloopperiode en het dunningspercentage zijn per boomsoort verschillend. De effecten van het beheer zijn een variërende stikstofbeschikbaarheid (gering na dunnen en groot na kappen) en een betere simulatie van de biomassa: teruggang in biomassa van de bomen na dunnen, en na kappen een enorme toename van de biomassa van de kruiden. Ook het hakhoutbeheer (voor eiken-, wilgen- en elzenhakhout) heeft veel invloed op de biomassa, al is verder onderzoek naar de biomassaverdeling over de functionele typen noodzakelijk. Toevoeging van beide beheersvormen geeft een duidelijke verbetering te zien van de simulatie van de bosontwikkeling.
    Effecten van een veranderend bosbeheer op de houtkwaliteit; een methode om de invloed van veranderingen in het beheer op de houtkwaliteit te bekijken, toegepast op douglas
    Wijk, M.N. van; Schelhaas, M.J. ; Edelenbosch, N.H. - \ 1999
    Wageningen : IBN-DLO, Instituut voor Bos- en Natuuronderzoek - 86
    bosbouw - bomen - bosbedrijfsvoering - bosbouwkundige handelingen - conservering - houteigenschappen - pseudotsuga menziesii - kwaliteit - nederland - forestry - trees - forest management - forestry practices - conservation - wood properties - pseudotsuga menziesii - quality - netherlands
    Kosten en doelrealisatie van bosbeheer
    Raffe, J.K. van; Wieman, E.A.P. - \ 1999
    Nederlands Bosbouwtijdschrift 71 (1999)4. - ISSN 0028-2057 - p. 157 - 159.
    bosbedrijfsvoering - bossen - bosbouw - bosbouwkundige handelingen - onderzoek - onderzoeksprojecten - verjonging - conversie - houtteelt conversie - houtteeltkundige systemen - conservering - natuurbescherming - herstel - biodiversiteit - kosten - kostenanalyse - kosten-batenanalyse - rentabiliteit - rendement - natuur - forest management - forests - forestry - forestry practices - research - research projects - regeneration - conversion - silvicultural conversion - silvicultural systems - conservation - nature conservation - rehabilitation - biodiversity - costs - cost analysis - cost benefit analysis - profitability - returns - nature
    Enkele resultaten van het IBN-DLO onderzoek 'Kosten en doelrealisatie van omvorming naar kleinschalig gestructureerd bos'. Voor een aantal omvormingsscenario's werden de bedrijfseconomische kosten en opbrengsten en de winst (of verlies) aan natuurwaarden bepaald. Verder uitleg over het kennissysteem waar dit onderzoek deel van uitmaakt
    Paalhout uit jonge Robinia beplantingen
    Rots, J. ; Oosterbaan, A. - \ 1999
    Nederlands Bosbouwtijdschrift 71 (1999)4. - ISSN 0028-2057 - p. 176 - 179.
    robinia pseudoacacia - bosbouw - bebossing - houtteelt - bosbouwkundige handelingen - groei - plantenontwikkeling - stamvorm - milieufactoren - palen (poles) - plantmateriaal - oorsprong - plaatsen op afstand - verzorgen van jonge opstanden - robinia pseudoacacia - forestry - afforestation - silviculture - forestry practices - growth - plant development - stem form - environmental factors - poles - planting stock - origin - spacing - tending
    Resultaten van onderzoek naar de groei en het aandeel paalhout van jonge Robinia beplantingen op voormalige landbouwgrond, en de invloed daarop van herkomst, plantafstand en behandeling
    If timber production did not require cutting down trees ... communicating timber management in society
    Schanz, H. - \ 1999
    Nederlands Bosbouwtijdschrift 71 (1999)6. - ISSN 0028-2057 - p. 232 - 236.
    bosbouw - bosbouwkundige handelingen - hout - houtsoorten - productie - bosbedrijfsvoering - samenleving - interacties - public relations - openbare mening - attitudes - communicatie - voorlichting - forestry - forestry practices - wood - timbers - production - forest management - society - interactions - public relations - public opinion - attitudes - communication - extension
    De 'slachthuis-paradox' in de bosbouw; mensen houden van bos en van hout, maar niet van de noodzakelijke tussenstap: houtproductie en houtkap. Mogelijkheden om meer sociale acceptatie te krijgen voor de houtproductie-functie van het bos
    Bosbouw in Canada : aan de vooravond van duurzaam bosbeheer?
    Bartelink, H.H. ; Hees, A.F.M. van; Bos, J.M. van den; Mangelmans, P.J.J. - \ 1999
    Nederlands Bosbouwtijdschrift 71 (1999)3. - ISSN 0028-2057 - p. 119 - 124.
    bossen - bosbouw - bosbouwkundige handelingen - houtteelt - duurzaamheid (sustainability) - bosbeleid - bosbedrijfsvoering - biodiversiteit - brits-columbia - quebec - nova scotia - canada - forests - forestry - forestry practices - silviculture - sustainability - forest policy - forest management - biodiversity - british columbia - quebec - nova scotia - canada
    Bosbouwbeleid en bosbouwpraktijk in British Columbia, Quebec en Nova Scotia. Verslag van een studiereis met aandacht voor certificering, duurzaam beheer, voorlichting, biodiversiteit, recreatie, 'first nations' problematiek, onderzoek, beheer en beleid
    Conservation and utilization of natural resources in the East Usambara forest reserves: conventional views and local perspectives
    Kessy, J.F. - \ 1998
    Wageningen University. Promotor(en): Paul Richards, co-promotor(en): M. Wessel. - [S.l.] : S.n. - ISBN 9789054858096 - 168
    bosbouw - bossen - natuurreservaten - natuurbescherming - bosbouwkundige handelingen - sociale economie - natuurlijke hulpbronnen - landgebruik - pachtstelsel - bebossing - tanzania - bosproducten anders dan hout - nationaal vermogen - forestry - forests - nature reserves - nature conservation - forestry practices - socioeconomics - natural resources - land use - tenure systems - afforestation - tanzania - non-wood forest products - national wealth
    The importance of conserving biological resources and the need for managing these resources for present and future generations has been given much attention internationally in the past three decades. These ideas have been emphasized in key documents such as the Brundtland report as well as in international conventions such as the global convention on biodiversity which followed the Rio meeting in 1992. The challenge in implementing these ideas lies in finding the proper trade-offs between current and future utilization of natural resources. Their success depends very much on the kind of policy reforms undertaken by nations to accommodate both local and international interests. Relevant policy adjustments are rarely observed in developing countries. For example, in Tanzania forest policies of the 1950s and early 1960s are still in use despite the recent developments in thinking about forest conservation issues. Conventional conservation approaches still dominate despite current emphasis on the need to involve all relevant stakeholder groups in preparing forest conservation plans. This approach often neglects the interests and value systems of the different groups of stakeholders with ultimate deleterious impact on forest resources.

    This study was conducted to examine the values, perceptions and actions with respect to forest resources of various stakeholders in the East Usambaras in Tanzania. This forest area has a high degree of species diversity and endemism that is threatened by increasing human pressure on resources. Conceptually the research was based on the appreciation of the existence of varying value systems between different stakeholders in relation to forest resources in the East Usambarasas, e.g. conservationists, estate holders and local villagers. The research focused on the collection of empirical evidence to substantiate the disparity of value systems amongst different stakeholders, and on the analysis of the impact of this disparity and possible modalities for reconsiliation reconciliation he objective of the study study was to investigate the potentials and limitations of involving local communities and other stakeholders in conserving the East Usambara forests, and to propose appropriate development strategies for harnessing such potentials. In order to reach this objective, the nature of various stakeholders' activities in relation to the forests was studied and the impact of such actions on long-term biodiversity conservation prospects in the area was assessed.

    An extensive literature search indicated a variety of arguments concerning the nature and extent of problems in natural resource management and the range of recommended approaches in solving such conservation problems. Different perceptions on fundamental concepts in biodiversity conservation exist; these reflect the diversity of values that individuals and social organizations attach to natural resources. For effective management of conservation areas these perceptions should be reconciled, and global and local interests should be balanced. This indicates the need to assess the significance of indigenous forest management systems and to augment the conventional approach to managing nature reserves with community management of forest resources. These ideas were used to formulate the key concepts and analytical framework for this study.

    The research consisted of the collection of information on both technical and sociological aspects of forestry. Because of this, a variety of research methods were deployed such as participatory rural appraisal, a general questionnaire survey and several more specialized surveys. The specialized surveys consisted of (a) several assessments of the different types forest products collected by local people, (b) a forest survey to ascertain the impact of human activities on the natural forests, and (c) a survey to assess the nature and extent of domestication of forest plants by local people. Additional information was collected through in-depth interviews with key informants, field observations and study of secondary data.

    The research started with a reconnaissance of twenty villages out of the total of fifty-four villages in the East Usambaras. These rapid village appraisals entailed both formal and informal discussions. The investigation aimed to expose the general characteristics of different villages and to provide the basis for selection of case study villages. Six villages were subsequently selected as case study villages representing the various ecological conditions in the area. These included Kisiwani, Mikwinini, Kwamzindawa, Potwe-Ndondondo, Hemsambia and Vuga.

    In all case study villages an open ended questionnaire was administered to solicit data on socio- economic conditions, forest products utilization trends, and local people's perceptions on a variety of conservation and development aspects. In each village a random selection of 20% of the households was made; in total 292 households were surveyed. Also several surveys on the use of forest products were carried out. An investigation of the different building materials of forest origin commonly used by villagers was done in five out of the six case study villages. The species used for building purposes and their quantities were estimated by surveying 41 houses which were under construction. In five villages a study was made of items of forest origin used at household level. In a sample of 10% of the households (135 households) all utensils derived from materials of forest origin were recorded. Also a market survey was carried out to collect information on the nature and amounts of both wood and non-wood forest products which are commercialized. On three markets 16 merchants were interviewed and their supply of products measured. A study was also made about the extent of human disturbance to the forest reserves as a result of forest products collection. The extent of the disturbance resulting was assessed in 150 sample plots of 0. 1 ha in size established at 100 to 200m, 500m and 1000m from the forest edge. In these plots forest characteristics such as species composition, signs of human impact and forest regeneration were recorded. Finally, in three villages a farm survey took place to record the presence and use of plants of forest origin on farmer fields.

    Data analysis was both quantitative and qualitative. The findings from the reconnaissance survey and rural appraisals were analyzed to provide insight for the more detailed surveys which were to follow. Information collected through the questionnaire survey was coded and analyzed with the SPSS statistical program for social sciences. The coding involved structuring the responses from the open- ended questionnaire and assigning them nominal values for analytical purposes. Considering the nature of the study mainly descriptive statistics were used. Data collected from the building materials survey, survey of household used items, market survey, forest sampling and domestication survey were analyzed using the Q&A4 database and Harvard Graphics 3.0 programs. Species names and synonyms were cross-checked using Kewensis database. Content analysis was used to analyze qualitative information from indepth interviews, and participant observations.

    The research findings presented in this book focus on the socio-economic conditions in the area, the values of the forests for local people, the effects of forest utilization, and the need to search for alternatives in managing the forest reserves and conserving their biodiversity.

    In the East Usambara basically three types of (agro)forestry systems are present: natural forests, forest plantations and on-farm tree growing systems. These forests are under the management responsibility of either the state, district or village institutions, estates or private persons. The natural forests are surrounded by a countryside occupied by very heterogenous human population, which is increasing rapidly because of both natural growth and immigration. Both subsistence and commercial agriculture is taking place. Commercial agriculture is dominated by tea and sisal estates, while subsistence agriculture consists of mixed cropping systems on farms of about three hectares in size. Farmers practice shifting cultivation using short fallow periods and local farming techniques. In some cases when shade trees are required such as for the cultivation of cardamom, or when locally- valued trees are present. not all trees are removed. But in general, due to poor soils the agricultural practices are often detrimental to the environment. In addition farmers also cultivate permanent homestead plots. A range of formal and informal institutions governing land use practices were discerned in the area. However, these institutions are not harmoniously organized to pursue conservation initiatives.

    Forests are very valuable to local communities in terms of both cultural and utilitarian benefits. Many different tree products are collected either for household use or sale. Forest plants provide fuelwood (33 species). poles (35 species), withies (32 species), ropes (11 species), foods (28 species), medicines (185 species) and household utensils (83 species). The annual per capita consumption of fuelwood was estimated at 1.7 cubic meters while the annual consumption of forest vegetables was estimated to be about 12 kg per household. The different products are collected either from the forest reserves, estate plantations or privately grown trees; collection in the forest reserves still predominates. Besides these utilitarian functions the local people also value forests for religious (e.g. traditional rainmaking ceremonies) and environmental values. The role of forests for regulating hydrological and micro-climate conditions and its significance for agricultural production are well recognized.

    The management of the forest reserves is still dominated by a conventional conservation approach that tends to alienate communities from conservation areas. Despite conservation regulations, human activities in the forest still continue. Illegal collection of forest products has affected the composition and structure of the forests adversely. The destruction of trees is most intensive near the forest edge, while animal trapping becomes more intensive with increasing distance from the forest edge. The harvesting of forest products by local people has resulted in the reduction of stocking level of trees from the estimated normal tree density of 650 stems/hectare to about 500 stems per hectare. The diameter distribution of trees has also been affected: trees with small diameters dominate close to the forest edge (up to 200m from the forest edge), whereas trees have a larger diameter deeper in the forest. Near the forest edge also many coppiced trees are present: respectively 49% and 42% of all coppiced trees were found in the 100-200m and 200-500m range from the forest edge, against about 9% deeper into the forest. Also the number of dead stumps decreases as the distance from the forest edge increases, but the reverse is the case for debarked trees. Illegal collection of forest products affected both endemic and non-endemic species.

    The local villagers are not just using the forest resources, they have also developed various management practices for the forest resources valued by them. For instance, villagers from Vuga and Hemsambia communally manage about 30 hectares of natural forest in the public lands. This forest was traditionally used for ritual purposes, but had been mismanaged by irresponsible village leaders. To prevent further depletion of this forest, the villagers agreed on a set of rules and regulations governing the utilization of resources in this forest and appointed a forest management committee. These initiatives were complementary to the conservation efforts by the Forest Division in other forest reserves in the area. Another example of local management efforts is the on-farm cultivation of tree species of forest origin for both consumptive and non-consumptive use. Such domestication concerns trees providing food, medicine, construction, lumber and local tools, or providing ecological services such as water conservation, shade and support to crops. About 10% of the domesticated species are endemic or near endemic.

    Although the needs and perceptions of the local farmers and conservationists are not always contradictory, in practice substantial gaps between the values and perceptions of various stakeholders interests in forests exist. Different interest groups have different perceptions of what biodiversity entails and how it should be conserved. Most professionals, donor agents and the educated elite understand and appreciate the importance of biological diversity from ecosystem down to genetic level. Their evaluation of the need for biodiversity conservation tends to focus specifically at ecosystem and species level. But the local people view the importance of the biodiversity of rests in terms the products and services that they can derive from the forests. Both professionals and local people consider the need for intergenerational flow of benefits from forests. However, professional conservationists are predominantly occupied with endangered species, centers of endemism, future prospects of new commercial, e.g. pharmaceutical, products and future use of genetic resources. Whereas local people are considering the livelihood of their descendants in terms of availability of rainfall, traditional medicines, fuelwood and building materials. This contrast in perception on the relevance of biodiversity is illustrated by the fact that conservationists pay more attention to the fact that 25% (about 710 species) of all vascular plant species and 18% (48 species) of all tree species are (near) endemic in the East Usambara, than to the fact that about 350 tree species (of which less than 6% of the endemic species) are used by the local population. Nor do they appreciate the fact that local people have taken conscious efforts to conserve around 100 tree species (of which about 20 endemic species) by cultivating them.

    A third interest group with specific perceptions on -the conservation of the natural resources in the Usambaras consists of the private commercial estates, particularly the tea estates. This interest group focuses specifically on two important forest benefits- rainfall and fuelwood. While rainfall boosts production, fuelwood supplies energy to company boilers. Future management of the forests in the area, as far as this, interest group is concerned, should pay attention to the catchment potential and supply of fuelwood from various sources, including plantations outside the forest reserves.

    Obviously, all three interest groups value the forests, be it for different reasons. Thus, they have at least in common that no group is in favor of forest depletion. The central challenge to the management of the forests is to build cooperative alliances between these groups, taking full account of the different value frameworks they bring to forest conservation. It is only when the specific interests of each group of forest user is considered, that these groups will develop interest in cooperation with the Forest Division in managing the forests. The main weakness of the current forest management is that it provides neither the forum nor the opportunity for different stakeholders to express their interests in relation to the forests. It is only when such a framework for expressing, debating, contesting and resolving differences of interest is in place that each interest group will respect the interest of other groups and develop cooperative norms. The study ends therefore with the outlining of a Stakeholder Reconciliation Model (SRM), which serves to address key issues such as policy formulation, land- use planning, communication and reconciliation of competing stakeholder claims. It is suggested, that this is an essential institutional prerequisite for achieving sustainable conservation of the forest resources in the East Usambaras.

    Vergelijkend onderzoek naar de gebruikswaarde van twaalf Nederlandse en veertien Belgische klonen van populier. Comparative research on characteristics of twelve Dutch and fourteen Belgian poplar clones
    Kranenborg, K.G. ; Vries, S.M.G. de - \ 1998
    Wageningen : IBN-DLO (IBN-rapport 359) - 28
    forestry - trials - hybrids - tree breeding - trees - plant breeding - clones - silviculture - forestry practices - growth - environmental factors - netherlands - belgium - bosbouw - proeven - hybriden - boomveredeling - bomen - plantenveredeling - klonen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - belgië
    In voor- of najaar verplanten? Een proef met gewone esdoorn
    Schuring, W. ; Das, C. - \ 1998
    Nederlands Bosbouwtijdschrift 70 (1998)2. - ISSN 0028-2057 - p. 66 - 69.
    bosbouw - beplanten - aanslaan van het gewasbestand - seizoenen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - forestry - planting - stand establishment - seasons - silviculture - forestry practices - growth - environmental factors
    Conservation and utilization of natural resources in the East Usambara forest reserves: conventional views and local perspectives.
    Kessy, J.F. - \ 1998
    Wageningen : Wageningen Agricultural University (Tropical Resource Management Papers 18) - ISBN 9789054858096 - 168
    bosbouw - bossen - natuurreservaten - natuurbescherming - bosbouwkundige handelingen - sociale economie - natuurlijke hulpbronnen - landgebruik - pachtstelsel - bebossing - tanzania - bosproducten anders dan hout - nationaal vermogen - forestry - forests - nature reserves - nature conservation - forestry practices - socioeconomics - natural resources - land use - tenure systems - afforestation - tanzania - non-wood forest products - national wealth
    Groei en groeiplaats van de zomereik, de wintereik en de Amerikaanse eik in Nederland
    Burg, J. van den - \ 1997
    Wageningen : IBN-DLO - 104
    bosbouw - standplaatsfactoren - bepaling van groeiplaatshoedanigheden - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bomen - nederland - quercus robur - quercus petraea - quercus rubra - forestry - site factors - site class assessment - silviculture - forestry practices - growth - environmental factors - trees - netherlands - quercus robur - quercus petraea - quercus rubra
    Groei en groeiplaats van de zwarte els en van de witte els in Nederland
    Burg, J. van den - \ 1997
    Wageningen : IBN-DLO - 57
    bosbouw - standplaatsfactoren - bepaling van groeiplaatshoedanigheden - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bomen - nederland - alnus glutinosa - alnus incana - forestry - site factors - site class assessment - silviculture - forestry practices - growth - environmental factors - trees - netherlands - alnus glutinosa - alnus incana
    Groei en groeiplaats van de beuk in Nederland
    Burg, J. van den - \ 1997
    Wageningen : IBN-DLO - 60
    bosbouw - standplaatsfactoren - bepaling van groeiplaatshoedanigheden - bomen - bodemkarteringen - kaarten - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - fagus sylvatica - forestry - site factors - site class assessment - trees - soil surveys - maps - silviculture - forestry practices - growth - environmental factors - netherlands - fagus sylvatica
    Groei en groeiplaats van de grove den en de Corsicaanse den in Nederland
    Burg, J. van den - \ 1997
    Wageningen : IBN-DLO - 90
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bepaling van groeiplaatshoedanigheden - bomen - nederland - forestry - silviculture - forestry practices - growth - environmental factors - site class assessment - trees - netherlands
    Trends in het ecologisch functioneren van bossen
    Bouwma, I.M. ; Olsthoorn, A.F.M. - \ 1997
    Wageningen : IBN-DLO - 77
    bosbouw - plantensuccessie - periodiciteit - vegetatie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bossen - milieubescherming - conservering - plantenecologie - nederland - forestry - plant succession - periodicity - vegetation - silviculture - forestry practices - growth - environmental factors - forests - environmental protection - conservation - plant ecology - netherlands
    Het Europese bos groeit sneller
    Nabuurs, G.J. ; Olsthoorn, A.F.M. ; Dik, E.J. - \ 1997
    Nederlands Bosbouwtijdschrift 69 (1997)1. - ISSN 0028-2057 - p. 24 - 27.
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - europa - forestry - silviculture - forestry practices - growth - environmental factors - europe
    Eind augustus '96 is in Freiburg het eindresultaat van het project 'Groeitrend in Europese bossen' gepresenteerd. Het boek is een bundeling van 22 case studies in 12 Europese landen naar de ontwikkeling van de groei in de laatste decennia
    Groeiplaatsen als basis voor bostypologie; vaste grond onder de voeten van bosbeheerders
    Wolf, R.J.A.M. ; Dort, K.W. van; Vrielink, J.G. - \ 1996
    Nederlands Bosbouwtijdschrift 68 (1996)5. - ISSN 0028-2057 - p. 177 - 189.
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - vegetatietypen - bossen - classificatie - bodemkarteringen - kaarten - nederland - forestry - silviculture - forestry practices - growth - environmental factors - vegetation types - forests - classification - soil surveys - maps - netherlands
    Fenologie en groei van bomen in relatie tot klimaatverandering
    Kramer, K. ; Mohren, G.M.J. - \ 1996
    Nederlands Bosbouwtijdschrift 68 (1996)2. - ISSN 0028-2057 - p. 73 - 78.
    bosbouw - klimaatverandering - paleoklimatologie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - Nederland - forestry - climatic change - palaeoclimatology - silviculture - forestry practices - growth - environmental factors - Netherlands
    Onderzoek naar de groei van tamme kastanje (Castanea sativa) in Nederland
    Oosterbaan, A. - \ 1996
    Bosbouwvoorlichting 35 (1996)2. - ISSN 0166-8986 - p. 18 - 18.
    biomassa - milieufactoren - bosbouw - bosbouwkundige handelingen - groei - houtaanwas - nederland - houtteelt - opstandsontwikkeling - opstandsstructuur - bomen - castanea sativa - biomass - environmental factors - forestry - forestry practices - growth - increment - netherlands - silviculture - stand development - stand structure - trees - castanea sativa
    Samenvatting van IBN-rapport 197
    Changing forest management strategies in Sudan : a challenge for forestry educational systems
    Mahir, S.S. - \ 1996
    Agricultural University. Promotor(en): W. van den Bor; N.G. Röling. - S.l. : Mahir - ISBN 9789054854951 - 263
    bosbouw - bosbedrijfsvoering - theorie - duurzaamheid (sustainability) - opbrengsten - bosbouwkundige handelingen - sociale economie - voorlichting - onderwijs - sociale bosbouw - landgebruik - pachtstelsel - bebossing - inheemse kennis - sociale verandering - sudan - sociale processen - forestry - forest management - theory - sustainability - yields - forestry practices - socioeconomics - extension - education - social forestry - land use - tenure systems - afforestation - indigenous knowledge - social change - sudan - social processes

    This study is an effort to understand the way various categories of social actors go about their interaction with the management of forest resources in Sudan. By providing an overview and description of the motives, perceptions, and management objectives and strategies of social actors, the study tries to contribute towards better understanding of the social, economic and cultural factors influencing the resource management. The specific objectives of this study include:
    (1) Investigation of how social actors interact with forest resources in an era of rapidly changing conditions.
    (2) Get a better understanding of how changes in management objectives and strategies are influencing and are influenced by knowledge processes.
    (3) Analyze present forestry education's curriculum.
    (4) Explore possibilities of incorporating what we learn during the course of this study to propose a model for development of curriculum for forestry education in Sudan.

    This dissertation is written on the basis of empirical data collected from various individuals, groups and institutions involved in forest resources management in Sudan. The field work for the study was carried out mainly in the Central region of Sudan. However, the author's own experiences and those of other officials who worked in other locations, made the scope of the study not limited to geographical boundaries of the region.

    For the data collection, a combination of methodological instruments such as discussions, semi-structured interviews and participant observation, were used iteratively. Besides, taking a social actor as a unit of analysis, the study has used a hybrid of the systems' and the actors' perspectives as the main analytical tool.

    The main findings of this study indicate that:

    First, whereas, a forest is the unit of concern for officials, it is the tree which draws villagers' attention more than the forest as such. However, in general social actors see trees and forests as sources and signs of life. Besides, various actors attach different social, economic and/or cultural meanings to trees/forests. Consequently, they develop varying management objectives and strategies. In this regard, this study shows that similarity between foresters' and villagers' objectives is the exception rather than the rule. Foresters' management objectives are focused on management of forests for provision of forest goods and services for the nation, whereas villagers keep trees for social-cultural-spiritual-economic reasons, but rarely for firewood alone. Sometimes, what is important for villagers is seen as of 'minor importance' to foresters.

    Second, villagers traditionally, did not care about ownership of forests. However, ownership of valued-trees was well known. Notwithstanding such a situation, the government in Sudan intervened to manage the resource. Nonetheless, abolishment of the traditional Native Administrative system together with many other factors led to the situation where the state was unable to manage the resources on a sustainable basis. Hence, some of the tree/forest resources acquired the characteristics of the unowned, none-property resources.

    Third, most of the foresters see forest management mainly as consisting of a series of context-free technical activities, while villagers perform trees/forests management as part and parcel of their overall land use.

    Fourth, this study exposes social actors' appreciation concerning positive changes in each other's attitudes and behaviours and their willingness to manage forest resources jointly. Nevertheless, villagers and their leaders as well as officials have to be aware of and prepared for their new rights and responsibilities.

    Fifth, this study manifests that the formal forestry knowledge in Sudan is based on the assumption that wood is the main product. In most of their experiments forestry researchers look mainly into wood, and did not pay enough attention to non-timber- products. In addition, extension officers tend to disseminate unified, ready-made messages to various clients' segments. As well, in spite of the shown appreciation of local people's forestry knowledge, foresters rarely take villagers' observations and comments seriously.

    Sixth, women are becoming increasingly involved in forestry activities and the number of female foresters is increasing. Taking into consideration the fact that the rural Sudanese culture in many places does not allow easy interaction between male extension officers and village women, the need for female forestry extension officers seems to be well understood.

    Seventh, the following are among the learning points in relation to villagers' knowledge activities as depicted from this study:
    (1) For villagers researching and learning are inseparable. Deploying their surrounding environment in its totality, villagers carefully observe and learn experientially.
    (2) Local people's knowledge is embedded into different kinds of rituals and spiritual beliefs.
    (3) Villagers do not tend to reach to consensus and unified kind of knowledge and solutions.
    (4) Villagers normally exchange information among themselves during greetings; direct and indirect asking; certain occasions and locations such as funerals, market places and days, and religious/cultural feasts.

    Eighth, the findings of this study reveal that none of social actors alone has the technical/managerial capacity pertinent to sustainable management of forest resources. The necessary knowledge base is rather fragmented and unevenly scattered among different actors. Hence, we argued that in the absence of a suitable knowledge and information system, appropriate management of forest resources will be difficult. Forestry education has a role to play in facilitation of such knowledge and information system. Nonetheless, many economic, didactical and organizational problems remain as constraints for present institutions to perform better roles.

    Ninth, the results of this study came to support the idea that education is but one element which influences foresters' attitudes and behaviour. In reality, foresters' performance is determined by a composite of inter-related factors such as the work environment. Under the prevailing situation, learners and educators have neither enough time nor good motivation for creation of favourable learning environments.

    The main recommendations of this study are:
    (1) Foresters should take other social actors' perceptions, knowledge and management objectives into consideration when deciding about official management objectives and strategies.
    (2) Forestry educational institutions will and should have a role to play in facilitating various forest resources managers getting around a platform and discuss, learn and coordinate their resources to manage the resources on a sustainable basis. However, before being able to play such a role, they should start to see their roles as "experts' bureaux", but instead try to develop networking institutions.
    (3) Moreover, in an era of fast change, forest managers should learn more about learning. Nevertheless, to facilitate such kinds of learning, forestry educational institutions need to restructure their curricula involving other social actors and create channels for ongoing monitoring.
    (4) However, all the above mentioned requirements will be of limited effect in the absence of an overall conducive environment. Again, educators should not wait for these improvements to come, instead they should work very hard for the creation of such a conducive educational and learning environment.

    As a contribution towards development of such educational and learning environment, a model for forestry curriculum development has been proposed.

    NOPEX/Forest-Dynamo. Ground data collection and data analysis report : : fieldcampaigns in 1994 - 1995
    Oevelen, P.J. van; Woodhouse, I.H. - \ 1996
    Wageningen : Landbouwuniversiteit Wageningen (Rapport / Landbouwuniversiteit, Vakgroep Waterhuishouding 70) - 74
    remote sensing - toepassingen - bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - luchtkarteringen - zweden - remote sensing - applications - forestry - silviculture - forestry practices - growth - environmental factors - aerial surveys - sweden
    Groei en ontwikkeling van de menging Douglas-beuk; meer dan de som der delen?
    Bartelink, H.H. ; Tünnissen, A.T.F.M. - \ 1996
    Nederlands Bosbouwtijdschrift 68 (1996)1. - ISSN 0028-2057 - p. 2 - 6.
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - gemengde bossen - bomen - fagus sylvatica - pseudotsuga menziesii - gemengde opstanden - forestry - silviculture - forestry practices - growth - environmental factors - mixed forests - trees - fagus sylvatica - pseudotsuga menziesii - mixed stands
    Het nedersaksische groeiplaatsclassificatiesysteem en zijn toepasbaarheid in Nederland.
    Fanta, J. ; Kuiper, B. ; Bianchi, F.J.J.A. ; Rattink, M. - \ 1996
    Nederlands Bosbouwtijdschrift 68 (1996). - ISSN 0028-2057 - p. 168 - 170.
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - vegetatietypen - bossen - classificatie - duitsland - forestry - silviculture - forestry practices - growth - environmental factors - vegetation types - forests - classification - germany
    Phenology and growth of European trees in relation to climate change
    Kramer, K. - \ 1996
    Agricultural University. Promotor(en): J. Goudriaan; G.M.J. Mohren. - S.l. : Kramer - ISBN 9789054854647 - 210
    bosbouw - fenologie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - klimaatverandering - paleoklimatologie - Europa - forestry - phenology - silviculture - forestry practices - growth - environmental factors - climatic change - palaeoclimatology - Europe
    Research topics

    The relationships between climate and both phenology and growth of some important European tree species were studied to evaluate the potential impacts of climate change on trees and forests in Europe. In order to make such assessments, insight is required on the mechanisms how climatic variables interact with plant processes. The topics addressed in this study were: (1) the modelling of phenology, (2) the consequences of climate change on spring frost damage, (3) the importance of phenotypic plasticity, (4) the importance of phenology on the effects of climate change on growth of monospecies deciduous forests, and (5) the importance of phenology on the effects of climate change on growth of mixed-species deciduous forests.

    Modelling phenology

    To evaluate the impacts of climate change on growth of temperate deciduous tree species, the onset and cessation of the growth must be accurately described. A review is presented on eight models predicting the date of leaf unfolding depending on temperature. These models were fitted using 57 years of observations on the date of leaf unfolding of Fagus sylvatica in The Netherlands, and used to predict 40 years of similar observations collected in Germany. As conflicting experimental evidence exist on the role of photoperiod on leaf unfolding of Fagus sylvatica, photoperiod was incorporated into each of these models.

    The timing of leaf unfolding could best be described by a model in which the effects of chilling temperatures (-5 to +10°C) and forcing temperatures (>0°C) operate sequentially in time, according to a triangular and logistic function, respectively. Including photoperiod reduced the predicting power of this model.

    Spring frost damage

    Two studies presented in literature evaluate the effect of increasing winter temperature on the probability of spring frost damage to trees. However, one study predicted an increase, while the other predicted a decrease in the probability of spring frost damage. It is unclear whether the disparity is because: (1) different models were used, (2) different climatic warming scenarios used, or (3) the tree species at the different locations respond differently to warmer winters. To evaluate the effects of climatic warming to Larix decidua, Betula pubescens, Tilia platyphylla, Fagus sylvatica, Tilia cordata, Quercus rubra, Quercus robur, Fraxinus excelcior, Quercus petraea, Picea abies and Pinussylvestris in The Netherlands and in Germany, both models were fitted to long series of observations on the date of leaf unfolding of these tree species. The impact of the two scenarios (uniformly and non-uniformly changing winter temperature) on the date of leaf unfolding and on the probability of freezing temperature around that date was evaluated. To test the importance of adaptation to local climate, hypothetical provenance transfers were analysed.

    For tree species in The Netherlands and Germany the probability of spring frost damage will decrease, provided the variability in temperature does not change. The contradictory results found in literature could be ascribed to differences among provenances adapted to their local climate, rather than to differences between either the models or the climatic warming scenarios used in these studies.

    Plasticity

    To evaluate the potential response of individual trees to climatic warming, phenological observations of clones of Larix decidua, Betula pubescens, Tilia cordata, Populus canescens, Quercus robur, Fagus sylvatica, and Picea abies transferred over a large latitudinal range in Europe were analysed. The magnitude of the clone's response was compared to that of genetically different trees of the same species along a part of the latitudinal range, which were assumed to have adapted to their local climate.

    The responses of the date of leaf unfolding and leaf fall of the clones to temperature are similar in magnitude to those of the genetically different trees. This demonstrates that trees possess a considerable plasticity and are able to respond phenotypically to a major change in their local climate. For the clones of Larix decidua and Quercus robur the growing season may shorten with increasing temperature, because leaf fall is advanced more than leaf unfolding. In Betula pubescens and Populus canescens, leaf unfolding and leaf fall are advanced equally, whereas in Tilia cordata and Fagus sylvatica the date of leaf fall seems to be unaltered but leaf unfolding advances with increasing temperature. These differences in the duration of the growing season in response to increasing temperature may alter the competitive balance between the species in mixed stands.

    Descriptive dynamic models showed that most of the variance of the date of leaf unfolding can be accounted for by temperature. However, a generally applicable model of leaf fall based on temperature and/or photoperiod could not improve the null model, i.e. the mean date of leaf fall, because of variability in other environmental factors.

    The lowest temperature around the date of leaf unfolding and leaf fall differed among the clones. The hypothesis that the survival of the clones is curtailed by spring frosts was supported. Thus, these lowest temperatures around leaf unfolding may represent thresholds below which the species cannot survive.

    It is argued that these thresholds may be a particularly sensitive means to evaluate the impacts of climatic warming on the geographical distribution of tree species.

    Growth of monospecies forests

    The importance of three phenological types of deciduous tree for the effects of climate change on growth of monospecies forests was evaluated using the model FORGRO. The climate change scenarios used were a doubling of the C02 concentration (700 μmol mol -1) and an increase in temperature ranging from 0 to 7°C. To elucidate the relative importance of photosynthesis and allocation for this evaluation, models with different levels of mechanistic detail of photosynthesis and allocation were used. The photosynthesis approach of FORGRO was compared to the Farquhar and Von Caernmerer approach as formulated in PGEN (FORGRO-PGEN). Similarly, the allocation approach of FORGRO was compared to the transport-resistance approach, as formulated in the ITE-Edinburgh model (ITE-FORGRO). A sensitivity analysis was performed to ascertain whether the response of gross photosynthesis to a climate change scenario depends on the value assigned to parameters in these models, and to compare this sensitivity with the differences found between the phenological types. The differences in the response of annual gross photosynthesis ( Pg,a ) to the climate change scenarios between the phenological types were smaller according to ITE- FORGRO as compared to FORGRO. These differences are of a similar magnitude when comparing the two photosynthesis models. Furthermore, FORGRO-PGEN showed that the response of Pg,a to a 2 x [ 2 CO ] increases with rising temperature, thus compensating for the increase in respiration. For both FORGRO and ITEFORGRO, this C0 2 and temperature interaction was not found. Consequently, in these models the increase in respiration exceeded the increase in gross photosynthesis at the higher range of temperature rise. The sensitivity analysis showed that the models differ in the sensitivity of the response of Pg,a to a 2 x [C 2 O ] scenario combined with a temperature rise of 2°C ( C700 / T2 ), when parameter values change by ±25%. In FORGRO-PGEN, the magnitude of the response of Pg,a depended on the values of some of its parameters, especially those determining the Michaelis-Menten kinetics of Rubisco, which for these parameters exceeded the differences between the phenological types in this scenario. In both FORGRO and ITE-FORGRO, this sensitivity is similar to or less than the difference between the phenological types in the C700 / T2 scenario.

    Growth of mixed-species forests

    Using the same three phenological types and climate change scenarios, the effects of differences in phenology and spring frost damage on growth in mixed-species stands were evaluated using the models FORGRO and HYBRID. FORGRO highlights potential growth in managed forests, whereas HYBRID highlights feedbacks of carbon, water and nitrogen cycles in General Vegetation Types, based on gap model theory. Furthermore, the importance of inaccuracy of the phenological model for growth in mixed-species stands was evaluated by comparing the modelling approach with a regression approach.

    The results of the climate change scenarios indicate for both FORGRO and HYBRID that: (1) the differences in NPP of the three phenological types considered are enhanced when grown in a mixed-species stand compared to a monospecies stand; and (2) the consequences of frost damage on growth is more prominent in mixed-species stands than in monospecies stands.

    Considering the accuracy of the modelling approach compared to the regression approach for the timing of leaf unfolding and spring frost damage, the sequential model of leaf unfolding shows a similar response of the NPP as the regression approach, both for the monospecies and the mixed-species situation. The modelling approach yields, however, larger differences in the NPP between the phenological types because the model predicts a greater advancement of leaf unfolding than the regression model. Comparing the regression approach to the modelling approach for frost hardiness, the regression approach shows a greater frequency of frost damage, because according to the model, the minimum level of frost hardiness is attained after the date of leaf unfolding, thus reducing this frequency.

    The differences in phenological response to temperature can be used to evaluate the consequences of climate change on the geographical distributions of species.

    Oogsttechniek heeft grote invloed op bewaring hout voor energiedoeleinden
    Gigler, J.K. ; Bosma, A.H. - \ 1995
    Landbouwmechanisatie 46 (1995)8. - ISSN 0023-7795 - p. 16 - 17.
    energie - energiegebruik - energiebronnen - bosbouw - bosbouwtechniek - bosbouwkundige handelingen - brandhout - stapelplaats - houtkap - stamhout - natuurlijke hulpbronnen - salicaceae - opslag - bomen - nuttig gebruik - hout - arbeidskunde - energy - energy consumption - energy sources - forestry - forestry engineering - forestry practices - fuelwood - landings - logging - logs - natural resources - salicaceae - storage - trees - utilization - wood - work study
    Elektriciteit uit energiegewassen als wilg kan in de toekomst realiteit worden. Het IMAG-DLO onderzoekt of de Zweedse kennis van en ervaring met de wilgenteelt ook in Nederland past
    Ruim twintig jaar beplantingsproef Broekpolder : proefveldresultaten over de periode 1970 - 1991
    Peeters, J.P. - \ 1994
    Wageningen : IBN-DLO (IBN - rapport 107) - 155
    bosbouw - bebossing - baggerspeciedepots - industrieterreinen - mijnstort - bodemvruchtbaarheid - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - havens - bagger - stort - sediment - modder - Nederland - zuid-holland - westland - forestry - afforestation - spoil banks - industrial sites - mine spoil - soil fertility - silviculture - forestry practices - growth - environmental factors - harbours - dredgings - spoil - sediment - mud - Netherlands - zuid-holland - westland
    Growth and nutrition of Douglas fir, Scots pine and pedunculate oak in relation to soil acidification
    Visser, P.H.B. de - \ 1994
    Agricultural University. Promotor(en): N. van Breemen; G.R. Findenegg; W.G. Keltjens. - S.l. : De Visser - ISBN 9789054852902 - 185
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bomen - bodemchemie - bodemaciditeit - verzuring - beluchting - voedingsstoffenopname (planten) - bodem ph - plantenfysiologie - neerslag - chemische eigenschappen - zuurgraad - zure regen - forestry - silviculture - forestry practices - growth - environmental factors - trees - soil chemistry - soil acidity - acidification - aeration - nutrient uptake - soil ph - plant physiology - precipitation - chemical properties - acidity - acid rain

    In a Douglas fir ( Pseudotsuga menziesii (Mirb.) Franco) and in a Scots pine ( Pinus sylvestris L.) stand on sandy soil in the Netherlands, inputs of water, nutrients and acid loads were changed for four years. Effects of soil changes on growth and nutrition were compared with similar foreign experiments, and with some soil-tree relationships in an oak ( Quercus robur L.) stand, which had different soil types within the site. Water limitations in the stands were demonstrated by a 40% to 50% increase in tree basal area growth from water additions of 3 mm d -1or more. Needle N and K contents were depressed and needle shedding was retarded in autumn by irrigation in the Douglas fir stand. In both coniferous stands mineralization and nitrate leaching were enhanced by the moister soil conditions. The modest growth response to nutrient applications in addition to irrigation, proved that no nutrient deficiencies were present at the sites, although foliar P and K increased instantly. The application of dissolved K, Mg and Ca to both acid forest soils increased Al dissolution and decreased Ca/Al ratios in soil solution. This soil reaction was even stronger when applying dissolved (NH 4 ) 2 SO 4 and was explained by the combined effect of soil exchange processes and root uptake of the applied cations, both increasing soil acidification. The applied (NH 4 ) 2 SO 4 initially enhanced tree growth, later followed by growth reduction in the forest stand and tree death in a pot trial at similar NH 4 supply rates.

    Douglas fir growth was higher at optimal water and nutrient applications when atmospheric loads were excluded. The reduced NH 4 inputs resulted in a decrease of NO 3 leaching, in a lower needle N concentration and tended to decrease Al concentrations and Al/Ca ratios in soil solution relative to the treatment with atmospheric loads.

    Transpiration of Douglas fir, as measured from sapflow, was drastically reduced during summer drought. Irrigated trees showed optimal transpiration rates and were found to absorb water more readily after rain events relative to previously water-stressed trees. NH 4 applications in a pot trial initially increased shoot growth and transpiration of juvenile Douglas fir, but strong soil acidification later impaired root functioning and water uptake.

    De bosbouw vergt een holistische benadering.
    Oldeman, R.A.A. - \ 1994
    Nederlands Bosbouwtijdschrift 66 (1994)1. - ISSN 0028-2057 - p. 13 - 19.
    conservering - bosbedrijfsvoering - bosbouw - bosbouwkundige handelingen - nederland - sociale economie - conservation - forest management - forestry - forestry practices - netherlands - socioeconomics
    Verloofing: misbruik van bossen of acceptabele bosbeheersmaatregel?
    Filius, A.M. - \ 1994
    Nederlands Bosbouwtijdschrift 66 (1994)6. - ISSN 0028-2057 - p. 226 - 234.
    bosbouw - gemengde bossen - bosbouwkundige handelingen - kosten - rentabiliteit - bosbouweconomie - bossen - bosbedrijfsvoering - nederland - gemengde opstanden - veluwe - gelderland - forestry - mixed forests - forestry practices - costs - profitability - forest economics - forests - forest management - netherlands - mixed stands - veluwe - gelderland
    Kosten per ha van omvorming van douglas naar eik/groveden en eik/groveden/Japanse lariks voor de Veluwe en kantekeningen bij het bosbeheerbeleid ten aanzien van verloofing
    Bosbeleidskunde in ontwikkeling; een systematische benadering.
    Vliet, C.J.M. van - \ 1993
    Nederlands Bosbouwtijdschrift 65 (1993)3. - ISSN 0028-2057 - p. 136 - 146.
    bosbouw - bosbouwkundige handelingen - sociale economie - regering - overheidsbeleid - bedrijfsvoering - forestry - forestry practices - socioeconomics - government - government policy - management
    Bomen over bossen en mensen in 't verschiet
    Maaren, A. van - \ 1993
    Wageningen : LU - 33
    bosbouw - bosbouwkundige handelingen - sociale economie - hoger onderwijs - sociaal milieu - colleges (hoorcolleges) - bosbouweconomie - bossen - bosbedrijfsvoering - economisch beleid - nederland - sociografie - sociale situatie - veluwe - gelderland - openbare redes - forestry - forestry practices - socioeconomics - higher education - social environment - lectures - forest economics - forests - forest management - economic policy - netherlands - sociography - social situation - veluwe - gelderland - public speeches
    Rede Landbouwuniversiteit Wageningen, 24 juni 1993
    Taaktijden voor de boomkwekerij
    Lookeren Campagne, P. van - \ 1992
    Wageningen : IMAG-DLO (Nota / Instituut voor Mechanisatie, Arbeid en Gebouwen 203)
    boomkwekerijen - bosbouw - bosbouwkundige handelingen - functieuitoefening - arbeid (werk) - plantenkwekerijen - tijd - werkplanning - arbeidskunde - bos- en haagplantsoen - forest nurseries - forestry - forestry practices - job performance - labour - nurseries - time - work planning - work study - woody nursery stock
    Specialisatie in de boomkwekerij
    Spenkelink, H. - \ 1992
    Boskoop : Proefstation voor de Boomkwekerij (Rapport / Boomteeltpraktijkonderzoek nr. 18) - 46
    arbeidsverdeling - boomkwekerijen - bosbouw - bosbouwkundige handelingen - Nederland - houtachtige planten als sierplanten - specialisatie - gespecialiseerde landbouw - division of labour - forest nurseries - forestry - forestry practices - Netherlands - ornamental woody plants - specialization - specialized farming
    Bedrijfseconomische analyse van de teelt van naaldhoutbosplantsoen : vollegrondsteelt vergeleken met plug- en containerteelt (project 3300; activiteit 03)
    Spenkelink, H. - \ 1992
    Boskoop : Proefstation voor de Boomkwekerij (Rapport / Boomteeltpraktijkonderzoek nr. 19) - 32
    containers - financiën - bosbouweconomie - bosbedrijfsvoering - boomkwekerijen - bosbomen - bosbouw - bosbouwkundige handelingen - nederland - houtachtige planten als sierplanten - potcultuur - bomen - slangen (buizen) - pinus sylvestris - pseudotsuga menziesii - pinopsida - containers - finance - forest economics - forest management - forest nurseries - forest trees - forestry - forestry practices - netherlands - ornamental woody plants - pot culture - trees - tubes - pinus sylvestris - pseudotsuga menziesii - pinopsida
    Resultaten van een dunningsproef met toekomstbomen in es
    Oosterbaan, A. ; Dik, E.J. - \ 1991
    Wageningen : De Dorschkamp (Rapport / De Dorschkamp Instituut voor Bosbouw en Groenbeheer nr. 630) - 34
    bosbouw - bomen - dunnen - habitus - levensvorm - plantenontwikkeling - nederland - onderzoek - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - fraxinus excelsior - bosopstanden - forestry - trees - thinning - habit - life form - plant development - netherlands - research - silviculture - forestry practices - growth - environmental factors - fraxinus excelsior - forest stands
    Aanleg en beheer van bos en beplantingen
    Schuetz, P.R. ; Tol, G. van - \ 1990
    Wageningen : Pudoc - 504
    bosbouw - klimaat - houtteelt - houtkap - bosbouwtechniek - arbeidskunde - bosbouwkundige handelingen - bosschade - bosplagen - achteruitgang, bossen - afsterving - houtmeetkunde - bosbedrijfsvoering - bosbouweconomie - bosproducten - bos- en houtproductenindustrieën - handel - marketing - economie - bossen - bosbescherming - bospathologie - forestry - climate - silviculture - logging - forestry engineering - work study - forestry practices - forest damage - forest pests - forest decline - dieback - mensuration - forest management - forest economics - forest products - forest products industries - trade - marketing - economics - forests - protection of forests - forest pathology
    De betekenis van de watervoorziening voor de boomgroei in Nederland : voorgeschiedenis, onderzoek en resultaten
    Burg, J. van den - \ 1990
    Wageningen : De Dorschkamp (Rapport / De Dorschkamp Instituut voor Bosbouw en Groenbeheer nr. 599) - 98
    bosbouw - bodemwater - permeabiliteit - absorptie - hygroscopiciteit - bodembescherming - waterbescherming - erosie - hydrologie - beheer van waterbekkens - wortels - plantenontwikkeling - bosschade - beschadigingen door droogte - beschadiging door hitte - schade - vergoeding - nederland - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - boswaardebepaling - forestry - soil water - permeability - absorption - hygroscopicity - soil conservation - water conservation - erosion - hydrology - watershed management - roots - plant development - forest damage - drought injury - heat injury - damage - compensation - netherlands - silviculture - forestry practices - growth - environmental factors - forest valuation
    De jeugdgroei van enkele inheemse loofboomsoorten in relatie tot de groeiplaats
    Jager, K. - \ 1990
    Wageningen : De Dorschkamp (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 596) - 56
    bosbouw - bomen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - waterrelaties - voedingsstoffen - wortels - bodemchemie - bodemeigenschappen - hoogte - diameter - volume - bepaling van groeiplaatshoedanigheden - bebossing - groene zones - heggen - nederland - forestry - trees - silviculture - forestry practices - growth - environmental factors - water relations - nutrients - roots - soil chemistry - soil properties - height - diameter - volume - site class assessment - afforestation - green belts - hedges - netherlands
    Resultaten van praktijkbekalkingen in eerste- en tweede- generatie - heidebebossingen in de boswachterij Ruinen
    Burg, J. van den - \ 1990
    Wageningen : De Dorschkamp (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 577) - 73
    bosbouw - bomen - voedingsstoffenbehoeften - bossen - bodemvruchtbaarheid - vegetatietypen - bodemchemie - bodemaciditeit - verzuring - beluchting - voedingsstoffenopname (planten) - bodem ph - planteffecten - bodem - humus - bodemprofielen - minerale gronden - horizonten - mineralen - as - planten - mineraalgehalte - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - bosopstanden - bemesting - drenthe - forestry - trees - nutrient requirements - forests - soil fertility - vegetation types - soil chemistry - soil acidity - acidification - aeration - nutrient uptake - soil ph - plant effects - soil - humus - soil profiles - mineral soils - horizons - minerals - ash - plants - mineral content - silviculture - forestry practices - growth - environmental factors - netherlands - forest stands - fertilizer application - drenthe
    Evaluatie experimenteel omvormingsbeheer naar natuurlijk bos.
    Koop, H. ; Platje, E.R.P. ; Verschoor, P. - \ 1990
    Nederlands Bosbouwtijdschrift 62 (1990)6. - ISSN 0028-2057 - p. 174 - 181.
    conservering - bosbedrijfsvoering - bosbouw - bosbouwkundige handelingen - planning - bomen - pinus sylvestris - natuurlijke opstanden - conservation - forest management - forestry - forestry practices - planning - trees - pinus sylvestris - natural stands
    Damage-controlled logging in managed tropical rain forest in Suriname
    Hendrison, J. - \ 1990
    Agricultural University. Promotor(en): M.M.G.R. Bol. - S.l. : Hendrison - ISBN 9789090038520 - 204
    bosschade - bosbouwkundige handelingen - velling - uitsleep - bosbouw - transport - houtkap - mens - menselijke activiteit - suriname - forest damage - forestry practices - felling - skidding - forestry - transport - logging - man - human activity - suriname

    Concern about worldwide deforestation and exploitation of the tropical rain forests has led to friction between national governments, wood industries and timber trade on the one hand, and scientists and environmental organizations on the other. One way to safeguard the tropical rain forests is to avoid human interference and to use forests only as nature reserves and as buffer zones of environmental protection. Some vulnerable tropical rain forests and those with unique flora and fauna should, indeed, be treated in this way. Most forests, however, have the potential to produce timber and other products on a sustainable basis provided that they are managed wisely. This study is concerned with sustained timber production of tropical rain forests, particularly with damage control during timber harvesting.

    The harvesting study is part of multidisciplinary research to develop a forest management system for sustained timber production in Suriname. The research started in the 1960s on an experimental scale in the northern Forestry Belt of Suriname. At first, a monocyclic silvicultural system was chosen with the aim of converting selectively logged rain forests by silvicultural measures into stands of valuable commercial timbers in a period of 60 to 80 years (Schulz, 1960; Boerboom, 1965). The long rotation period, intensive weed control and tending of future crop trees made this system economically unattractive.

    In the 1970s, a polycyclic sivicultural system was tested, envisaging timber harvests in felling cycles of 20 years by treatments of logged-over forest. This system, later known as CELOS Silvicultural System (CSS), was developed after further research (de Graaf, 1986; Poels, 1987; Jonkers, 1987). In 1981 harvesting studies were included to extend the CSS into a forest management system. Field experiments were carried out in order to compare controlled (organized) logging with conventional (unorganized, haphazardous) logging. These experiments covered damage to the remaining stand caused by felling and skidding of trees, the impact of skidding machines on the forest soil, and organizational and administrative aspects of logging.

    The research was carried out mainly in Mapane region, 100 km south-east of Paramaribo (Figs 2.1 and 3.1). Conventional, commercial logging operations and controlled logging experiments were studied in a forest area of 640 ha during the period 1982-1984. A number of observations were made in an area of 100 ha, 120 km south-east of Paramaribo, in the forest estate Patamacca, of the Bruynzeel Wood Company (BSH), the largest forest concession holder in Suriname.

    Felling and skidding impacts to the remaining stand were determined by mapping and calculating the affected forest area. Felling damage was assessed in terms of gaps (chablis) in the forest resulting from a felled tree, and also by the number of damaged trees per ha. Controlled felling, which includes directional felling based on a tree location map in order to facilitate skidding, was shown to reduce felling damage significantly. At a felling intensity of 8-10 trees per ha (20 m 3), approximatly 14% of the forest area was damaged in conventional felling compared with 8% in controlled felling. In controlled skidding, damage was restricted to 5-8% of the remaining forest, whereas in conventional skidding the affected area exceeded 14%. Skidding damage was also substantial (13%) in the organized harvesting operations of BSH, amounting to 7% due to pre-sorting operations of crawlers in the stump area and 6% due to wheeled skidding on trails.

    Soil damage may result from movement of skidders. As well as rutting and disturbance to the structure, the soil may also be compacted. The type and degree of compaction are determined by soil characteristics such as structure, texture, field moisture content and organic matter content, and by characteristics of the skidders such as gross vehicle weight, steering system, and tyre and track type. Soil compaction was measured on soil samples and with the aid of a penetrometer. The soil moisture was also assessed by determining the saturated conductivity (K factor) and pF value. Subjected to intensive machine traffic, primary skid trails (main trails from stump areas to log landings), were found to be highly compacted. Most secondary branch trails (log-collecting trails in the stump areas) were compacted to some degree, depending on traffic intensity.

    Trail sections with moisture content near field capacity were maximally compacted after a few round trips of the loaded skidder. Moisture content appeared to be a decisive factor in the soil degrading process. Soil recovery was a slow process, and skid trails used eight years previously were still found to be maximally compacted.

    Controlled logging was found to be more efficient than conventional logging. This was examined by measuring logging production in relation to effective crew and machine time, and also by studying the suboperations in a working cycle. Measures to control felling damage were not found to have a negative effect on production. Mean felling productivity was similar for both systems, being 0.07 man-day per m 3in the conventional and 0.08 man-days per m 3in controlled system. On an annual basis, skidding production under the controlled system was twice that of conventional logging. This difference can be explained in terms of planning and preparation of harvesting activities undertaken in the controlled system, and also the skidding method based on a pre-established skid trail network. The controlled skidding method was more efficient as 40% less machine time was required per unit of product transported.

    The research findings provided the basis for theCELOSHarvesting System (CHS) aiming at combining logging efficiency and damage prevention. Timber harvesting is based on planning and pre-harvesting preparations, work organization and adapted logging techniques.

    The cornerstone for planning is forest prospecting, that is a full (100%)enumeration of harvestable commercial trees. Prospecting data, including terrain characteristics, are mapped and recorded for the use of felling and skidding crews in searching for trees. The maps are also used to design a skid trail network for efficient terrain transport of logs from the stump area to landings along the truck roads. In this way a plan of operations can be made annually for all harvesting work.

    The skid trail system should be established prior to harvesting in order to facilitate tree felling according to the skidding pattern, thus combining damage prevention and skidding efficiency. The damaging effects of skidding in the stump area can also be reduced by winching logs to the trails. The additional costs of damage prevention are compensated by overall improvement in logging efficiency.

    The logging organization of a management unit is composed of one prospecting crew (5 men), one felling crew (3 men), one crawler tractor crew (2 men) and one wheeled skidder crew (2 men). This unit is supervised by an assistant manager (ranger). All field staff need to be trained in basic techniques such as tree spotting, scaling, and power saw operation to enable job rotation and thus greater flexibility in operation. Training of machine operators especially should focus on damage prevention and logging efficiency. Such an organizational unit should be able to harvest annually an area of 1000 ha.

    The CELOS Harvesting System and the CELOS Silvicultural System are the subsystems of the CELOS Management System (CMS) which has been designed for a forest unit of approximately 25 000 ha. Central to this polycyclic system are the management objectives and planning for the subsystems. A major aim is restriction of logging impacts to the soil and the remaining stand. Felling intensity is restricted, for instance for Suriname to 30 m 3/ha, in order to maintain the ecological, conservational, and protective functions of the forest. The present study gives guidelines for the layout of a standard management unit with a production target of at least 25 000 to 30 000 m 3per year and also indicates how harvesting and silvicultural operations can be integrated. The CELOS Management System is applicable in the northern Forestry Belt of Suriname and probably in similar forest types of the Amazon basin. Timber harvesting according to this system is applicable or adaptable to most lowland tropical rain forests.

    Groei en ontwikkeling van vier loofboomsoorten op zuiveringsslib van verschillende herkomst : verslag van een in de periode 1981 t/m 1984 uitgevoerde veldproef
    Luit, B. van; Smilde, K.W. ; Burg, J. van den - \ 1989
    Wageningen : De Dorschkamp (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 570) - 91
    bosbouw - mineralen - as - planten - mineraalgehalte - toxische stoffen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bosopstanden - bemesting - forestry - minerals - ash - plants - mineral content - toxic substances - silviculture - forestry practices - growth - environmental factors - forest stands - fertilizer application
    De invloed van fosforbemesting en bekalking op de groei na 30 jaar van een fijnsparopstand in de boswachterij Smilde, vak 12
    Burg, J. van den; Zielhorst, A.J.M. ; Boersma, F. - \ 1989
    Wageningen : "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 560) - 86
    bosbouw - kunstmeststoffen - behoeften - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - mineralen - as - planten - mineraalgehalte - achteruitgang, bossen - levensvatbaarheid - nederland - bosopstanden - bemesting - drenthe - forestry - fertilizers - requirements - silviculture - forestry practices - growth - environmental factors - minerals - ash - plants - mineral content - forest decline - viability - netherlands - forest stands - fertilizer application - drenthe
    Bosbemestingsmethoden : resultaten van een praktijkproef
    Leek, N.A. ; Wanningen, H. ; Hellinga, P.W. ; Hoksbergen, F.T.J. ; Schreuder, H.J. - \ 1989
    Wageningen : "De Dorschkamp", Instituut voor Bosbouw en Groenbeheer (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 568) - 238
    bosbouw - kunstmeststrooiers - luchtvaartuig - toepassingen via de lucht - onderzoek - bosbouwkundige handelingen - kosten - rentabiliteit - nederland - bosopstanden - bemesting - forestry - fertilizer distributors - aircraft - aerial methods - research - forestry practices - costs - profitability - netherlands - forest stands - fertilizer application
    Kapregeling in het bosbeheer in Nederland.
    Klein, J.P.G. de - \ 1989
    Nederlands Bosbouwtijdschrift 61 (1989)10. - ISSN 0028-2057 - p. 267 - 270.
    velling - bosbedrijfsvoering - bosbouw - bosbouwkundige handelingen - nederland - planning - verjonging - felling - forest management - forestry - forestry practices - netherlands - planning - regeneration
    Een reactie op "Algemene noties van bosbouw" door S. Klingen en J. Sevenster, betreffende het bosbeheer in Nederland (zie NBT nr. 3, 1989)
    Growth and development of Scots Pine in The Netherlands.
    Leersnijder, R.P. - \ 1989
    In: Unification of European forest pattern research : proceedings of a workshop organized by the Forest Ecosystem Research Network (FERN) of the European Science Foundation (EFS), held in Strasbourg, France, 24 - 26 April 1989 / Schmidt, P., Oldeman, R.A.A., Teller, A., - p. 115 - 118.
    biomassa - computersimulatie - milieufactoren - experimenten - bosbouw - bosbouwkundige handelingen - groei - houtaanwas - meting - nederland - houtteelt - simulatie - simulatiemodellen - opstandsontwikkeling - opstandsstructuur - statistiek - bomen - pinus sylvestris - biomass - computer simulation - environmental factors - experiments - forestry - forestry practices - growth - increment - measurement - netherlands - silviculture - simulation - simulation models - stand development - stand structure - statistics - trees - pinus sylvestris
    Bebossing van landbouwgronden : evaluatie - methodiek voor alternatief gebruik van beschikbare landbouwgronden
    Wit, A.P.W. de; Blom, J.C. ; Willems, A.J.H. - \ 1988
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 541) - 75
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - landbouw - bosbouweconomie - kosten - theorie - berekening - rentabiliteit - bosbouwkundige handelingen - sociale economie - productiekosten - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - agriculture - forest economics - costs - theory - calculation - profitability - forestry practices - socioeconomics - production costs
    Preventieve bestrijding van de populiereglasvlinder (Paranthrene tabaniformis Rott.) (Lepidoptera; Sesiidae) in kwekerijen met het systemisch insecticide Carbofuran
    Moraal, L.G. - \ 1988
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "de Dorschkamp" nr. 536) - 68
    carbofuran - bosschade - insectenplagen - chemische bestrijding - boomkwekerijen - bosbouwkundige handelingen - paranthrene tabaniformis - carbofuran - forest damage - insect pests - chemical control - forest nurseries - forestry practices - paranthrene tabaniformis
    Vooronderzoek naar de kosten van aanleg en onderhoud van bosplantsoen in het stedelijk gebied
    Rotteveel, K. - \ 1988
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 513) - 55
    bosbouw - bosbouwkundige handelingen - kosten - rentabiliteit - verzorgen van jonge opstanden - plantmateriaal - bosbomen - bosbouw in steden - beplanten - aanslaan van het gewasbestand - groene zones - openbare parken - recreatiegebieden - publieke tuinen - bosopstanden - forestry - forestry practices - costs - profitability - tending - planting stock - forest trees - urban forestry - planting - stand establishment - green belts - public parks - amenity and recreation areas - public gardens - forest stands
    Resultaten van een vergelijkend onderzoek naar de bruikbaarheid van Tacamahaca en Aigeiros klonen van populier op verschillende groeiplaatsen
    Peeters, J.P. - \ 1987
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 497) - 70
    bosbouw - bomen - hout - productie - standplaatsfactoren - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - forestry - trees - wood - production - site factors - silviculture - forestry practices - growth - environmental factors
    Simulation of forest growth, applied to douglas fir stands in the Netherlands
    Mohren, G.M.J. - \ 1987
    Agricultural University. Promotor(en): C.T. de Wit, co-promotor(en): R.A.A. Oldeman. - S.l. : Mohren - 184
    bosbouw - bomen - houtaanwas - opstandsontwikkeling - opstandsstructuur - biomassa - meting - experimenten - statistiek - simulatie - nederland - plantenfysiologie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - klimaat - atmosfeer - meteorologie - microklimaat - bodemkunde - pseudotsuga menziesii - forestry - trees - increment - stand development - stand structure - biomass - measurement - experiments - statistics - simulation - netherlands - plant physiology - silviculture - forestry practices - growth - environmental factors - climate - atmosphere - meteorology - microclimate - soil science - pseudotsuga menziesii
    Forest growth in relation to weather and soils is studied using a physiological simulation model. Growth potential depends on physiological characteristics of the plant species in combination with ambient weather conditions (mainly temperature and incoming radiation). For a given site, growth may be lower because of incomplete canopy closure, shortage of water and nutrients, and the occurrence of growth-disturbing factors such as pests, diseases, and damage to the plants, e.g. by windthrow or frost. Attention is focused on the main growth-limiting factors, i.e. canopy closure, and the availability of water, nitrogen and phosphorus, so that differences in growth between different sites can be explained as a function of the properties of plant and soil, and of the ambient weather at a particular site. The model is applied to even-aged Douglas fir stands in the Netherlands because of the availability of field data for testing and evaluating it.

    The life cycle of trees and forests encompasses many years, and in order to be able to study overall stand dynamics, the model aims at simulating growth over periods of several decades. This allows the results of the model to be evaluated against data from permanent field plots, that are also being used in conventional, descriptive research on growth and yield. Furthermore, simulating forest growth over such long periods makes the results from the model comparable with the results of practical forest management. Variations in growth during the year are caused by changes in incoming radiation, temperature and water availability in the soil. To simulate this, time intervals of one day are used for the main part of the simulation model.

    The particular value of simulation models in forestry lies in the possibility they offer of combining different aspects of growth in an overall approach, and of studying stand dynamics over a long period of time without having to rely entirely on expensive and time-consuming field trials. Moreover, in a situation where the environment for forest growth may change e.g. as the result of industrial pollution, or as a consequence of gradual climatic changes, modelling is one of the important means by which to assess these changes and potential damage.

    The subject of the study, an even-aged coniferous forest stand, is described in terms of the biomass components foliage, branches, stems and roots. These four components are the main state variables in the model. To enable comparisons to be made between the results from the model and the data from permanent field plots, only stem biomass and stem volume are considered, together with the number of trees. This reflects a top-down approach to growth, which is calculated as total stand growth per unit of soil surface area, before it is distributed over individual trees. In addition to state variables that denote biomass amounts, stand structure is also characterized by stand height, average dimensions of the tree crowns, and total depth of the rooted soil profile. All other state and intermediate variables of the trees (such as the Leaf Area Index of the stand), are derived from simulated biomass components and stand structure. In the model, ambient weather is characterized using meteorological data from a local weather station: total daily global radiation, daily minimum and maximum temperatures, daily vapour pressure of the air, average wind speed at 10 m above short vegetation, and precipitation. The latter is characterized by daily rainfall and the average number of rainfall events per day. Only the rooted soil profile is used to describe the soil compartment. Soil moisture retention properties are the main variables for the hydrological submodel. The simulation of nutrient dynamics is based on the total amount of nutrients retained in the rooted soil profile and incorporated in the stand biomass. Nutrient inputs to the system are described by forcing functions, and used as input to the model.

    Chapter 3 shows how primary production is calculated for the whole stand. Canopy assimilation is calculated from the distribution of photosynthetically active radiation over the foliage, together with the photosynthesis/light response curve at ambient temperature for the surface of an individual leaf. The assimilation submodel uses a three- point Gaussian integration, as described recently by Goudriaan (1986), and Spitters (1986). The distribution of photosynthetically active radiation over the foliage accounts for gaps in the canopy, and allows for clustering of the foliage, as in the case of grouping of needles around branches in old stands. Typical aspects of canopy assimilation in Douglas fir stands, are the evergreen habitus of the stand, and the generally low maximum photosynthesis rates, (around 15 kg CH 2 O ha -1h -1). These low rates of photosynthesis are coupled with high stomatal resistances for the diffusion of both carbon dioxide and water vapour.

    After canopy assimilation has been estimated, net growth is calculated by accounting for maintenance respiration, and by allocating the assimilates available for growth to the biomass components. Growth respiration is taken into account when converting assimilate products to structural dry matter. To calculate maintenance respiration, sapwood is distinguished from heartwood. It is found that the hypothesis (Boysen Jensen, 1928; Kira and Shidei, 1967) that tree growth declines with age of the trees because maintenance requirements increase with accumulation of stem biomass does not hold when maintenance requirements are related to sapwood only. Sapwood (like foliage, branches and roots) has a limited life-span, and the maximum value it attains during stand development depends on site productivity. This maximum value is reached within 15 years of the time of maximum annual increment. Growth respiration is calculated by taking the chemical composition of the biomass formed into account. The allocation of assimilates to the biomass components is based on a distribution key derived from published data. The distribution of growth over the biomass components changes during stand development, and also depends on the productivity of the site. Stem dry weight increment is converted to volume increment by dividing the estimated dry weight increment by the basic density of the stem wood formed, i.e. the oven-dry weight per unit of fresh volume. Individual tree increment is calculated by dividing total stem volume increment by the number of trees in the stand, and only an average value for diameter at breast height is calculated from tree volume and height, using an empirical regression equation.

    Chapter 4 describes the hydrological part of the model. The three main aspects considered in the model are: a) interception of precipitation by the canopy and the resulting net infiltration to the soil compartment; b) the soil moisture balance; c) and uptake and transpiration of soil moisture by the trees. Coniferous forests in western Europe are often located on sandy soils with a limited soil moisture holding capacity and restricted capillary rise. This means that in periods of drought, availability of soil moisture becomes limiting for growth. In the model, therefore, it suffices to simulate water availability with an elementary summary model that keeps track of soil moisture. Soil moisture content and the rate of infiltration are simulated by assuming that the soil horizons are filled to field capacity by a sharp wetting front proceeding from the top of the soil profile downwards. Root uptake is assumed to proceed until soil moisture is depleted to the wilting point. Field capacity and wilting point are derived from soil suction curves, and depend on physical soil characteristics.

    Tall forest stands have considerable aerodynamic roughness, and this means that the aerodynamic resistance to the transport of water vapour from the surface of the foliage to the overlying atmosphere is small (around 10 s m -1). Besides, the large stomatal resistance of Douglas fir needles results in a minimum canopy resistance for the transpiration flux of 100 to 200 s m -1; therefore, precipitation intercepted by the vegetation will evaporate at rates several times the transpiration rate under the same atmospheric conditions. Therefore, interception represents a real loss that has to be accounted for. To estimate interception, the amount of intercepted precipitation is subtracted from daily precipitation.

    Daily transpiration is estimated with the Penman-Monteith combination equation, with total canopy resistance as one of the input variables. This resistance depends on: a) the vapour pressure deficit of the air (here assumed to pose a lower limit on stomatal resistance), b) the water status of the foliage, expressed in terms of needle water potential, and c) the stomatal opening resulting from photosynthesis. All three effects on stomatal resistance are calculated independently, and the largest resistance is used in the model to estimate total canopy resistance. The influence of vapour pressure and plant water status (through needle water potential), Is assumed to be the same for all foliage in the canopy. The stomatal resistance estimated from net photosynthesis rates varies with varying photosynthesis rates inside the canopy. As in the calculation of canopy assimilation, a Gaussian integration procedure is used to estimate the weighted average foliage resistance. The resulting transpiration rates are found to be unexpectedly low during the growing season. Total annual transpiration, however, is in accordance with published data, and the simulated change in soil moisture during 1983 compares well with measurements from the field plots. It is concluded that on dry soils like those frequently occupied by coniferous stands in the Netherlands, water shortage may have considerable influence on growth, even though transpiration rates are low. In its present state the model can be used to calculate the reduction In growth caused by water shortage, for different sites, and for stands of different structure.

    In chapter 5 the simulation of nutrient dynamics and the influence of nitrogen and phosphorus on growth are described. As it has been shown many times that nitrogen and phosphorus may limit growth of coniferous stands on sandy soils, only these two elements are incorporated in the model. No attempt is made to model the dynamics of nitrogen and phosphorus in detail; instead, an elementary model with time steps of one year is used in combination with the simulations of daily canopy assimilation and hydrology. Soil supply of nitrogen and phosphorus is estimated from total soil content, by taking into account an unstable and a stable pool of nutrients in the soil, each with different turnover rates. The demand for nitrogen and phosphorus by the growing vegetation depends on the concentrations of these elements in the tissue, and on the amounts redistributed before dead biomass is shed, in combination with an estimated rate of biomass increment. By adjusting the concentration in the tissue for the next period of growth, demand and supply are balanced, and the influence of nutrient availability on growth during the following year is estimated using an empirical relationship between foliage nutrient concentration and growth. This approach assumes the existence of maximum and minimum concentrations of both nutrients in the tissue. Above the maximum concentration there is no further uptake; below the minimum, growth ceases.

    The final results from the model, together with the measurement series from permanent field plots are given in chapter 6. The field plots used to calibrate the model are discussed first; after this the model is tested against an independent set of data. Overall model behaviour seems to follow field measurements reasonably, both in the field plots used for calibration and in the independent (control) plot. Maximum increment rates as measured in the field are well reflected in the simulations, as is the decline in stem increment in older trees. Most of the discrepancies between predicted and real values are found to occur at higher ages of the stand. It is concluded that this is probably because the model overestimates light interception, because it takes no account of effects of uneven distributions of the trees in the field. This becomes more important when stands are thinned at high ages, when the crowns have only a limited ability to occupy the available growing space.

    Together with the evaluation of model behaviour, the value of the use of modelling in forestry in general, and of the use of a physiologically-based model like the one used here, is discussed. These models are needed for analysing growth and yield, and for contributing to the understanding of forest primary production. Moreover, they can be used to bridge the gap between widely different aspects of forest growth such as forest hydrology and forest nutrition. By integrating the main aspects of forest growth, these models also allow the main factors that determine total stand growth to be ascertained. As a result, possibilities for yield improvement, and the areas where research is mostly needed, can be identified. In the present case study, it appears that canopy growth often declines in the course of years because of decreased light interception. Current forestry practice in the Netherlands often includes an intensive thinning programme aimed at creating space for the individual crop trees. But this decreases stand growth. In general, this is not the intention, and therefore the efficacy thinning operations at higher stand ages that open up the stand to a degree that can no longer be utilized by the remaining trees, has to be reassessed.

    Not only does availability of soil moisture limit growth; nitrogen and phosphorus availability may also play an important role in determining the production level of a stand. The elementary model used indicates the extent to which both nitrogen and phosphorus may influence stand growth, and the results are evaluated against the results of fertilizer experiments carried out in Douglas fir on a range of sites during the 1950s and the 1960s (Blok et al., 1975). The increase In atmospheric input of nitrogen, resulting from, among others, intensive livestock farming and manure-spreading on agricultural lands, has greatly increased nitrogen supply. As a result, widespread phosphorus deficiency has become apparent. In the Netherlands, all but the best sites currently available suffer from severe phosphorus deficiency. This situation, where widespread nitrogen deficiency has changed into a deficiency of phosphorus, demands attention from researchers and forest managers. Increasing phosphorus availability through additional. fertilization can be expected to boost primary production and thus increase yield.

    One of the possible applications of the model is to calculate the growth potential of a wide range of available soil types and growing conditions, thereby allowing potential forest growth to be assessed. It can also be used to evaluate management interventions. If employed in a target-oriented mode the model could be used to evaluate the efficacy of applying fertilizer. Some of the growth- or stand-disturbing factors will have to be incorporated in the model before it can be used to calculate economic yield or optimal felling regimes.

    The simulation programme is available upon request.

    Vegetation structure, logging damage and silviculture in a tropical rain forest in Suriname
    Jonkers, W.B.J. - \ 1987
    Agricultural University. Promotor(en): R.A.A. Oldeman; J.H.A. Boerboom. - S.l. : Jonkers - 172
    bosbouw - oerbossen - tropische regenbossen - vegetatie - tropen - bossen - bosproducten - lagenstructuur - biomassa - bosschade - bosbouwkundige handelingen - velling - uitsleep - bebossing - verjonging - suriname - oude bossen - forestry - virgin forests - tropical rain forests - vegetation - tropics - forests - forest products - layer structure - biomass - forest damage - forestry practices - felling - skidding - afforestation - regeneration - suriname - old-growth forests

    In the first publication in this series, a polycyclic forest management system was formulated, in which three silvicultural treatments (refinements) were scheduled in a cutting cycle of twenty years. This system, which is referred to as the Celos Silvicultural System, is developed further in this study.

    Selective logging is the first action of forest management. Felling limits for most species need to be raised from 35 cm to 50 cm dbh to secure future harvests. If carried out properly, logging does not cause unacceptable damage to the stand. The forest responds to logging with a slow recovery process and a refinement is scheduled one to two years after felling to release commercial species. This treatment consists of cutting lianas and poison-girdling trees without commercial value, which are either larger than 40 cm dbh or 20 - 40 cm dbh and within 10 m of a commercial tree. A second treatment is necessary ten years after the initial harvest and the third one is scheduled a few years before the second cut. These follow-up treatments differ from the first one in the selection of trees to be poison-girdled.

    Het bosbedrijf: erop toeleggen of eraan overhouden?
    Maaren, A. van - \ 1987
    Nederlands Bosbouwtijdschrift 59 (1987)5. - ISSN 0028-2057 - p. 150 - 152.
    kosten - bosbouw - bosbouwkundige handelingen - houtkap - costs - forestry - forestry practices - logging
    Het verloop van de macro-elementgehalten in het blad van enige loofboomsoorten in een kwekerij in de zomer van 1982 en 1983 = Seasonal change in foliar macro-element concentrations of some broadleaves in a nursery in the summer of 1982 and 1983
    Burg, J. van den - \ 1986
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 419) - 81
    chemische analyse - boomkwekerijen - bosbouw - bosbouwkundige handelingen - houtachtige planten als sierplanten - planten - straatbomen - chemical analysis - forest nurseries - forestry - forestry practices - ornamental woody plants - plants - street trees
    Verslag van een proef met verschillende aanlegsystemen voor es (Fraxinus excelsior)
    Oosterbaan, A. - \ 1986
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 452) - 32
    bosbouw - bomen - plantmateriaal - handel - plaatsen op afstand - bosbouwkundige handelingen - kosten - rentabiliteit - struiken - onderlaag - Fraxinus excelsior - Nederland - betuwe - gelderland - forestry - trees - planting stock - trade - spacing - forestry practices - costs - profitability - shrubs - understorey - Fraxinus excelsior - Netherlands - betuwe - gelderland
    Rationeel beheer van wegbeplantingen
    Leek, N.A. ; Six Dijkstra, H.G. - \ 1986
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 433) - 98
    bosbouw - groene zones - heggen - bosbouwkundige handelingen - kosten - rentabiliteit - wegbeplantingen - wegbermplanten - efficiëntie - productiviteit - rationalisering - forestry - green belts - hedges - forestry practices - costs - profitability - roadside plantations - roadside plants - efficiency - productivity - rationalization
    Aanleg- en onderhoudskosten van beplantingen in recreatiegebieden : een onderzoek uitgevoerd in de Rottemeren, het Zuigerplaspark en het Lingebos = Costs of establishing and maintaining plantations in recreational areas
    Leek, N.A. - \ 1986
    Groen : vakblad voor groen in stad en landschap 42 (1986)2. - ISSN 0166-3534 - p. 16 - 21.
    recreatiegebieden - kosten - bosbouw - bosbouwkundige handelingen - groene zones - rentabiliteit - publieke tuinen - openbare parken - flevoland - zuid-holland - amenity and recreation areas - costs - forestry - forestry practices - green belts - profitability - public gardens - public parks - flevoland - zuid-holland
    Onderzoek is gedaan in drie recreatiegebieden met het doel inzicht te verkrijgen in de wijze waarop beplantingen in dergelijke gebieden worden beheerd; welke kosten het beheer bij de verschillende beplantingstypen met zich meebrengt, en aanbevelingen te doen voor verlaging van de beheerskosten
    Towards sustained timber production from tropical rain forests in Suriname, Special Paper IX World Forestry Congr. Mexico, 1985
    Boxman, O. ; Graaf, N.R. de; Hendrison, J. ; Jonkers, W.B.J. ; Poels, R.L.H. ; Schmidt, P. ; Tjon Lim Sang, R. - \ 1985
    Netherlands Journal of Agricultural Science 33 (1985). - ISSN 0028-2928 - p. 125 - 132.
    ecosystemen - bosbouw - bosbouwkundige handelingen - bossen - houtkap - planten - houtteelt - transport - tropische regenbossen - vegetatie - suriname - ecosystems - forestry - forestry practices - forests - logging - plants - silviculture - transport - tropical rain forests - vegetation - suriname
    De gevolgen van veranderingen bij het bosbeheer voor de bosoperaties
    Bol, M.M.G.R. ; Leek, N.A. - \ 1985
    Nederlands Bosbouwtijdschrift 57 (1985)10/11. - ISSN 0028-2057 - p. 348 - 357.
    bosbedrijfsvoering - bosbouw - bosbouwkundige handelingen - houtkap - planning - transport - forest management - forestry - forestry practices - logging - planning - transport
    Dit artikel is een bewerking van een bijdrage aan het IUFRO symposium "Human Impacts on Forests", Straatsburg 1984. Beschreven worden de achtergronden van de veranderingen die zich voordoen bij het bosbeheer dat in de laatste tijd meer gericht is op natuurlijke processen. Speciale aandacht is besteed aan werkmethoden, gebruik van hulpmiddelen en machines, en de bosoperaties.
    Verslag van een onderzoek naar de invloed van de bewortelbare ruimte en de kwaliteit van zandzuiveringsslibmengsels op de groei en de minerale voedingstoestand van Platanus x acerifolia op de Soederblomplaats te Rotterdam-Ommoord, zomer 1983 = Report of a research on the influence of rootable volume and quality of sand-sewage sludge mixtures on growth and mineral nutrient status of Platanus x acer
    Burg, J. van den - \ 1984
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 362) - 44
    bosbouw - bomen - wortels - plantenontwikkeling - mineralen - as - planten - mineraalgehalte - kroon - kroondak - bodemvruchtbaarheid - voedingsstoffen - waterrelaties - bodem - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - forestry - trees - roots - plant development - minerals - ash - plants - mineral content - crown - canopy - soil fertility - nutrients - water relations - soil - silviculture - forestry practices - growth - environmental factors
    Mensen en bossen
    Bol, M.M.G.R. ; Maaren, A. van; Oldeman, R.A.A. ; Wassink, J.T.J. - \ 1984
    Unknown Publisher (S.M.O.-informatief 84/4) - 83
    conservering - economische impact - milieubescherming - bosbouweconomie - bosbedrijfsvoering - bosbeleid - bosbouw - bosbouwkundige handelingen - bossen - sociale economie - conservation - economic impact - environmental protection - forest economics - forest management - forest policy - forestry - forestry practices - forests - socioeconomics
    De aard en de omvang van de ontbossingsprocessen en de rol van de mens hierin worden behandeld, waarna een aantal praktische aanbevelingen worden gedaan om het ontbossingsprobleem aan te pakken
    Growth and morphogenesis of shoot initials of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, in vitro
    Evers, P.W. - \ 1984
    Landbouwhogeschool Wageningen. Promotor(en): R.A.A. Oldeman, co-promotor(en): R.L.M. Pierik. - Wageningen : Evers - 250
    ongeslachtelijke voortplanting - knoppen - milieufactoren - bosbouw - bosbouwkundige handelingen - groei - in vitro kweek - plantenmorfologie - scheuten - houtteelt - stengels - bomen - vegetatieve vermeerdering - pseudotsuga menziesii - asexual reproduction - buds - environmental factors - forestry - forestry practices - growth - in vitro culture - plant morphology - shoots - silviculture - stems - trees - vegetative propagation - pseudotsuga menziesii
    An optimalized method of micropropagation of Douglas fir is described. Seasonal changes were found in optima for nitrate and sucrose in the medium and in the optimum for the light intensity during the culture of shoot initials. Differences in morphogenesis were obtained from shoot initials that had been isolated from buds in 10 topophysical positions on 2-year-old trees. These differences between the shoots were influenced by the medium, the light intensity, and by forcing or topping the mother trees or treating them with growth regulators. Shoots from each of the topophysical positions had a characteristic photosynthesis. A first attempt is made to compare in vivo flushing with the morphogenesis of shoot initials in vitro.
    Forests and forestry in national life
    Maaren, A. van - \ 1984
    In: Forest policy : a contribution to resource development / Hummel, F.C., - p. 1 - 19.
    bosbouw - bosbouwkundige handelingen - bossen - regering - wetgeving - regelingen - sociale economie - supervisie - forestry - forestry practices - forests - government - legislation - regulations - socioeconomics - supervision
    Groei en ontwikkeling van vier loofboomsoorten op zuiveringsslib van verschillende herkomst : verslag van een in de periode 1978 t/m 1980 uitgevoerde veldproef = Growth and development of four broadleaves on domestic sludges of various origin : report of a field triel, 1978 - 1980
    Burg, J. van den; Luit, B. van; Peeters, J.P. - \ 1983
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw De Dorschkamp no. 321) - 74
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bodemgiftigheid - havens - bodemvruchtbaarheid - voedingsstoffen - baggerspeciedepots - industrieterreinen - mijnstort - bosopstanden - bemesting - forestry - silviculture - forestry practices - growth - environmental factors - soil toxicity - harbours - soil fertility - nutrients - spoil banks - industrial sites - mine spoil - forest stands - fertilizer application
    Kostenmodellen voor eenrijige wegbeplantingen van eik en populier
    Leek, N.A. - \ 1983
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor onderzoek in de bos- en landschapsbouw "De Dorschkamp" no. 376) - 39
    bosbouw - bomen - bosbouwkundige handelingen - kosten - rentabiliteit - groene zones - heggen - forestry - trees - forestry practices - costs - profitability - green belts - hedges
    Onderhoudskosten van beplantingen in het recreatiegebied "Lingebos"
    Taenzer, B. - \ 1983
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 348) - 37
    bosbouw - bosbouwkundige handelingen - kosten - rentabiliteit - verjonging - verzorgen van jonge opstanden - bosplantages - openluchtrecreatie - recreatiegebieden - opstandsstructuur - opstandsontwikkeling - kostenanalyse - bosopstanden - forestry - forestry practices - costs - profitability - regeneration - tending - forest plantations - outdoor recreation - amenity and recreation areas - stand structure - stand development - cost analysis - forest stands
    Aanleg en beheer van bos en beplantingen
    Schuetz, P.R. ; Tol, G. van - \ 1982
    Wageningen : Pudoc - 504
    bosbeheer - handboeken - bosschade - bosbouweconomie - bosbedrijfsvoering - bosplagen - bosproducten - bosbouw - bosbouwtechniek - bosbouwkundige handelingen - bossen - houtteelt - bosbescherming - bospathologie - forest administration - handbooks - forest damage - forest economics - forest management - forest pests - forest products - forestry - forestry engineering - forestry practices - forests - silviculture - protection of forests - forest pathology
    Beoordeling en selectie van klonen van grauwe abeel (P. canescens) voornamelijk in de IJsselmeerpolders
    Birkenhaeger, B. - \ 1982
    Wageningen : De Dorschkamp (Mededeling / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 201)
    milieufactoren - bosbouw - bosbouwkundige handelingen - groei - habitus - hybriden - levensvorm - houtteelt - boomveredeling - bomen - proeven - populus canescens - nederland - flevoland - environmental factors - forestry - forestry practices - growth - habit - hybrids - life form - silviculture - tree breeding - trees - trials - populus canescens - netherlands - flevoland
    Grondwaterstandenproefveld "Geestmerambacht" : overzicht van meetgegevens over de periode 1973 t/m 1979
    Burg, J. van den - \ 1982
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor onderzoek in de bos- en landschapsbouw "De Dorschkamp" No. 290) - 96
    bosbouw - bodemwater - permeabiliteit - absorptie - hygroscopiciteit - waterrelaties - wortels - bodem - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - noord-holland - forestry - soil water - permeability - absorption - hygroscopicity - water relations - roots - soil - silviculture - forestry practices - growth - environmental factors - netherlands - noord-holland
    De betekenis van chloride voor bomen: toxische gehalten in blad, naalden en grond : een literatuuroverzicht = The significance of chloride for trees: toxic concentrations in foliage and soil : a literature review
    Burg, J. van den - \ 1982
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 323) - 123
    bosbouw - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bodemvruchtbaarheid - voedingsstoffen - bodemchemie - anorganische verbindingen - zoute gronden - alkaligronden - waterrelaties - wortels - bodemeigenschappen - bosschade - beschadigingen - erosie - planten - toxische stoffen - chloride - forestry - silviculture - forestry practices - growth - environmental factors - soil fertility - nutrients - soil chemistry - inorganic compounds - saline soils - alkaline soils - water relations - roots - soil properties - forest damage - injuries - erosion - plants - toxic substances - chloride
    Literatuurstudie over de relaties tussen het zoutgehalte in de bodem (het C-cijfer), het chloride-gehalte van blad en naalden, de groei en het optreden van zichtbare schadeverschijnselen. Voor een groot aantal geslachten en soorten zijn de C-cijfers, kritische chloride-gehalten en het chloride-gehalte, waarbij blad en naalden juist zichtbare schade gaan vertonen, opgenomen
    Groei en minerale voedingsstoffenvoorziening in het met rundveedrijfmest bemeste populierentoetsproefveld "Roder Heyde" (1973 t/m 1980)
    Burg, J. van den - \ 1982
    Wageningen : Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 297) - 44
    bosbouw - bomen - stalmest - mineralen - as - planten - mineraalgehalte - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - waterrelaties - bodem - voedingsstoffen - wortels - nederland - bosopstanden - bemesting - noord-brabant - forestry - trees - farmyard manure - minerals - ash - plants - mineral content - silviculture - forestry practices - growth - environmental factors - water relations - soil - nutrients - roots - netherlands - forest stands - fertilizer application - noord-brabant
    Groei en ontwikkeling van een beplanting van Populus 'Zeeland' op brak havenslib bij verschillende aanlegmethoden = Growth and development of a plantation of Populus 'Zeeland' on brackish harbour sludge at various methods of establishment.
    Burg, J. van den; Kolster, H.W. - \ 1982
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor onderzoek in de bos- en landschapsbouw "De Dorschkamp" no. 324) - 44
    bosbouw - bomen - bebossing - havens - bagger - stort - sediment - modder - beplanten - aanslaan van het gewasbestand - bosschade - beschadigingen - bodemeigenschappen - erosie - ploegen als grondbewerking - grondbewerking - baggerspeciedepots - industrieterreinen - mijnstort - waterrelaties - voedingsstoffen - wortels - bodemchemie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bosopstanden - bemesting - forestry - trees - afforestation - harbours - dredgings - spoil - sediment - mud - planting - stand establishment - forest damage - injuries - soil properties - erosion - ploughing - tillage - spoil banks - industrial sites - mine spoil - water relations - nutrients - roots - soil chemistry - silviculture - forestry practices - growth - environmental factors - forest stands - fertilizer application
    Effecten van kalverdrijfmest op zwarte balsem- en balsem-populieren : verslag van een bemestingsonderzoek in de periode 1977 t/m 1980 = Effects of liquid calf manure on black balsam poplars and balsam poplars : report of fertilization research in the period 1977-1980
    Burg, J. van den - \ 1982
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 296) - 71
    bosbouw - bomen - stalmest - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - bodemvruchtbaarheid - voedingsstoffen - mineralen - as - planten - mineraalgehalte - waterrelaties - bodem - wortels - bosopstanden - bemesting - forestry - trees - farmyard manure - silviculture - forestry practices - growth - environmental factors - soil fertility - nutrients - minerals - ash - plants - mineral content - water relations - soil - roots - forest stands - fertilizer application
    Aanleg- en onderhoudskosten van beplantingen in het recreatiegebied Zuigerplaspark
    Grimberg, G. ; Schaap, L. - \ 1982
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 295) - 51
    bosbouw - bosbouwkundige handelingen - kosten - rentabiliteit - beplanten - aanslaan van het gewasbestand - verzorgen van jonge opstanden - nederland - bosopstanden - flevoland - forestry - forestry practices - costs - profitability - planting - stand establishment - tending - netherlands - forest stands - flevoland
    Sustained timber production in the tropical rainforest of Suriname
    Graaf, N.R. de - \ 1982
    In: Proceedings of the joint workshop on management of low fertility acid soils of the American humid tropics, Paramaribo, Suriname, 23 - 26 November, 1981 / Wienk, J.F., de Wit, H.A., - p. 175 - 189.
    biomassa - bosbouw - bosbouwtechniek - bosbouwkundige handelingen - houtaanwas - houtkap - opstandsontwikkeling - opstandsstructuur - tropische regenbossen - vegetatie - arbeidskunde - suriname - biomass - forestry - forestry engineering - forestry practices - increment - logging - stand development - stand structure - tropical rain forests - vegetation - work study - suriname
    Het bosschap en de ontwikkeling van bos en de bosbouw
    Maaren, A. van - \ 1982
    Nederlands Bosbouwtijdschrift 54 (1982)11/12. - ISSN 0028-2057 - p. 348 - 354.
    bosbouw - bosbouwkundige handelingen - sociale economie - handelsvennootschappen - basisproducten - bossen - bosproducten - forestry - forestry practices - socioeconomics - trade associations - commodities - forests - forest products
    De ontwikkeling van jonge eikenopstanden (Quercus robur L.) in de boswachterij Vaals
    Oosterbaan, A. - \ 1981
    Wageningen : De Dorschkamp (Mededeling / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 190)
    milieufactoren - bosbouw - bosbouwkundige handelingen - groei - houtteelt - bomen - quercus robur - nederland - limburg - environmental factors - forestry - forestry practices - growth - silviculture - trees - quercus robur - netherlands - limburg
    De invloed van de stekafstand op de ontwikkeling van eenjarige populieren en de betekenis daarvan voor slaging en groei na het uitplanten
    Blok, H. ; Tol, G. van - \ 1981
    Wageningen : De Dorschkamp (Mededeling / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 187)
    milieufactoren - bosbouw - bosbouwkundige handelingen - groei - houtteelt - plaatsen op afstand - verplanten - bomen - environmental factors - forestry - forestry practices - growth - silviculture - spacing - transplanting - trees
    pH en boomgroei : een literatuuronderzoek = pH and tree growth : a literature study
    Burg, J. van den - \ 1981
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 282) - 596
    bosbouw - bodemchemie - bodemaciditeit - verzuring - beluchting - voedingsstoffenopname (planten) - bodem ph - samenvatten - literatuur - documentatie - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - forestry - soil chemistry - soil acidity - acidification - aeration - nutrient uptake - soil ph - abstracting - literature - documentation - silviculture - forestry practices - growth - environmental factors
    Een overzicht wordt gegeven van de betekenis van de pH voor de diverse boomsoorten afzonderlijk in verband met de geschiktheidsbeoordeling van gronden voor boomsoorten. Alleen literatuurgegevens over boomsoorten in de gematigde luchtstreken zijn in beschouwing genomen. Aandacht is vooral besteed aan de relatie tussen pH en groei. Andere aspecten, zoals relaties met schimmelziekten en luchtverontreiniging, worden slechts in het kort besproken. De literatuurgegevens zijn per geslacht, per soort en zo nodig per ras of cultivar samengevat. Dit rapport bevat tevens basisinformatie met betrekking tot de zure-regenproblematiek
    Een onderzoek naar de oorzaken van de slechte groei en conditie van wegbeplantingen van Populus x Euramericana 'Heidemij' langs autosnelwegen in West-Nederland in 1979 = An investigation into the causes of poor growth and condition in roadside plantations of Populus x Euramericana 'Heidemij' along motorways in the west part of the Netherlands in 1979
    Burg, J. van den; Schoenfeld, P.H. - \ 1981
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw " De Dorschkamp" no. 273) - 67
    bosbouw - bomen - vegetatie - wegbermplanten - nederland - groene zones - heggen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - waterrelaties - wortels - bodem - forestry - trees - vegetation - roadside plants - netherlands - green belts - hedges - silviculture - forestry practices - growth - environmental factors - water relations - roots - soil
    De invloed van gras- en kruidenvegetaties op de slaging en groei van eikenbezaaiingen op voormalige landbouwgronden = The influence of vegetation on survival and growth of oak seedings on former arable land
    Oosterbaan, A. ; Tol, G. van - \ 1981
    Wageningen : "De Dorschkamp" (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 268) - 20
    bosbouw - bomen - direct zaaien - aanslaan van het gewasbestand - onkruiden - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - ecologie - forestry - trees - direct sowing - stand establishment - weeds - silviculture - forestry practices - growth - environmental factors - netherlands - ecology
    Groei, behandeling en kwaliteit van jonge eikenopstanden (Quercus robur L.) in de boswachterij Vaals
    Oosterbaan, A. - \ 1981
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 253) - 29
    bosbouw - bomen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - houtaanwas - hoogte - diameter - grondvlak - quercus robur - nederland - zuid-limburg - forestry - trees - silviculture - forestry practices - growth - environmental factors - increment - height - diameter - basal area - quercus robur - netherlands - zuid-limburg
    Dry matter production of four Salix clones
    Birkenhaeger, B. - \ 1981
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw 'De Dorschkamp' no. 275) - 15
    bosbouw - bomen - soortenkeuze - selectie - biomassa productie - bepaling van groeiplaatshoedanigheden - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - forestry - trees - choice of species - selection - biomass production - site class assessment - silviculture - forestry practices - growth - environmental factors
    Growth of selectively logged tropical high forests : a global inventory of existing information, needed research and development and the implications for policy and management
    Andel, S. - \ 1981
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 248) - 29
    bosbouw - selectiekap - selectiesysteem - houtaanwas - opstandsontwikkeling - opstandsstructuur - biomassa - bosbouwkundige handelingen - sociale economie - tropen - subtropen - natuurlijke opstanden - forestry - selective felling - selection system - increment - stand development - stand structure - biomass - forestry practices - socioeconomics - tropics - subtropics - natural stands
    Growth and morphogenesis of shoot initials of douglas fir, Pseudotsuga menziessi (Mirb.) Franco, in vitro V. The influence of growth regulators
    Evers, P.W. - \ 1981
    Wageningen : Dorschkamp Research Institute for Forestry and Landscape Planning
    ongeslachtelijke voortplanting - knoppen - milieufactoren - bosbouw - bosbouwkundige handelingen - groei - in vitro kweek - plantenmorfologie - scheuten - houtteelt - stengels - bomen - vegetatieve vermeerdering - pseudotsuga menziesii - asexual reproduction - buds - environmental factors - forestry - forestry practices - growth - in vitro culture - plant morphology - shoots - silviculture - stems - trees - vegetative propagation - pseudotsuga menziesii
    Tien jaar beplantingsproef Broekpolder : proefveldresultaten over de periode najaar 1969 - najaar 1979
    Peeters, J.P. ; Stuurman, F.J. - \ 1980
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 235) - 146
    bosbouw - bebossing - baggerspeciedepots - industrieterreinen - mijnstort - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - zuid-holland - rotterdam - forestry - afforestation - spoil banks - industrial sites - mine spoil - silviculture - forestry practices - growth - environmental factors - netherlands - zuid-holland - rotterdam
    De invloed van hoge koperdoseringen aan een zandgrond op de groei en het kopergehalte van zwarte els en "Zeeland"-populier : (verslag van een in 1978 uitgevoerde potproef) = The influence of high copper doses on growth of black alder and "Zeeland" poplar and its foliar copper concentrations on a sandy soil (report of a pot trial in 1978)
    Burg, J. van den; Janssens, M.J.W.M. - \ 1980
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 214) - 28
    bosbouw - bomen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - kunstmeststoffen - behoeften - mineralen - as - planten - mineraalgehalte - bosopstanden - bemesting - forestry - trees - silviculture - forestry practices - growth - environmental factors - fertilizers - requirements - minerals - ash - plants - mineral content - forest stands - fertilizer application
    Aanleg- en onderhoudskosten van beplantingen in het recreatiegebied Rottemeren
    Leek, N.A. - \ 1980
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 231) - 38
    bosbouw - bosbouwkundige handelingen - kosten - rentabiliteit - beplanten - aanslaan van het gewasbestand - verjonging - verzorgen van jonge opstanden - bosplantages - groene zones - openbare parken - recreatiegebieden - publieke tuinen - economie - gebruikswaarde - economische impact - nederland - zuid-holland - forestry - forestry practices - costs - profitability - planting - stand establishment - regeneration - tending - forest plantations - green belts - public parks - amenity and recreation areas - public gardens - economics - use value - economic impact - netherlands - zuid-holland
    De groei van 'Robusta' populier op een bekalkte arme en een bekalkte matig rijke zandgrond : verslag van een in 1960 uitgevoerde potproef
    Burg, J. van den; Kolster, H.W. - \ 1980
    Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" no. 228) - 28
    bosbouw - bomen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - plantmateriaal - cultuurmethoden - forestry - trees - silviculture - forestry practices - growth - environmental factors - planting stock - cultural methods
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