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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    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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