Species mixing effects on forest productivity in the Netherlands
Lu, Huicui - \ 2017
Wageningen University. Promotor(en): G.M.J. Mohren, co-promotor(en): F.J. Sterck. - Wageningen : Wageningen University - ISBN 9789463436397 - 134
mixed forests - temperate zones - deciduous forests - soil fertility - light - yields - netherlands - gemengde bossen - gematigde klimaatzones - loofverliezende bossen - bodemvruchtbaarheid - licht - opbrengsten - nederland
Many monoculture forests (dominated by a single tree species) have been converted to mixed-species forests (dominated by more than one tree species) in Europe over the last decades. The main reason for this conversion was to increase productivity, including timber production, and enhance other ecosystem services, such as conservation of biodiversity and other nature values. In addition, it has been suggested that mixed-species forests are more resistant, resilient and stable to disturbances.
In line with the niche complementarity hypothesis, inter-specific differences in crown architecture, leaf phenology, shade tolerance and root distribution may allow tree species to partition resources in mixed forests. Such mechanisms may lead to a higher productivity of mixed forests versus monoculture forests, a phenomenon often referred to as overyielding. Interestingly, the stress-gradient hypothesis and the resource-ratio hypothesis suggests that such inter-specific interactions vary along a soil fertility gradient, but in different ways. The stress-gradient hypothesis emphasizes that more efficient partitioning increases overyielding at low fertility soils, whereas the resource ratio hypothesis considers that the denser packing of crowns on fertile soils allows for partitioning of light and overyielding on high fertility soils. Several studies have been carried out about species mixing effects on forest productivity, but so far their findings are ambiguous. Probably, this ambiguity comes from the sites that they studied, which differ in species, age, management history, and/or environmental conditions.
This thesis analyses the mixing effect on productivity in relation to the combination of species, stand age and soil fertility, and discusses possible consequences of forest management, for five two-species mixtures in the Netherlands: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)–beech (Fagus sylvatica L.), pine (Pinus sylvestris L.)–oak (Quercus robur L.), oak–beech, oak–birch (Betula pendula Roth) and pine–birch. These mixtures and their corresponding monoculture stands were studied using long-term permanent forest plots over multiple decades, but also using two inventories (around 2003 and 2013) across the entire Netherlands. These forest plots data were used together with empirical models at total stand level (chapter 2), species level (chapter 3) and tree level (chapter 4) to evaluate the mixing effect on forest productivity.
In chapter 2, four two-species mixtures and their corresponding monospecific stands were compared for productivity (volume stem wood in m3 ha-1 year-1). It was explored whether mixing species differing in leaf phenology and shade tolerance would lead to overyielding of mixed forest stands, and whether overyielding changes with stand development. In line with the niche complementarity hypothesis, the two evergreen–deciduous species mixtures (Douglas-fir–beech and pine–oak) showed overyielding whereas deciduous–deciduous species mixtures (oak–beech and oak–birch) did not. The overyielding was strongest for the Douglas-fir–beech mixture than the pine–oak mixture, which can be attributed to the greater difference in shade tolerance in the former mixture. Overyielding did not significantly change with stand development. It is argued that the regular thinning maintained the ability of species to partition resources, i.e. the complementary resource use in those mixed stands over all stand ages.
In chapter 3, it was analysed which of the two species in these four mixtures contributed to overyielding, and whether this overyielding changed along a soil fertility gradient. It was discovered that both the fast-growing and the slow-growing species could contribute to overyielding. Yet, it was mainly the fast-growing Douglas-fir that contributed to higher productivity in the Douglas-fir–beech mixtures, and the slow-growing oak that did so in the pine–oak mixtures. For both mixtures, the greatest relative productivity gain was achieved by mixtures on the poorer soils. At first sight, these results seem in line with the stress-gradient hypothesis and not the resource-ratio hypothesis. Yet, it was argued that not only complementary use of soil resources, but also use of light, may contribute to the higher productivity of mixed stands on the poorer soils.
In chapter 4, it was assessed how the growth of individual trees in mixtures was influenced by inter- and intra-specific competition, and whether this competition was mainly size-symmetric for soil resources or size-asymmetric for light on soils differing in fertility. This chapter focussed on three mixtures, i.e. oak–birch, pine–oak and pine–birch, which were available at sufficient numbers in the Dutch national forest inventory data. It was concluded that intra-specific competition was not necessarily stronger than inter-specific competition and this competitive reduction was less seen at lower soil fertility and dependent on species mixtures, which is not in line with the stress-gradient hypothesis. Moreover, size-asymmetric competition for light was more associated with tree basal area growth than size-symmetric competition for soil resources, suggesting that light is the most limiting resource. Competition for light was generally much stronger at high fertility soils, supporting the resource-ratio hypothesis. These results suggest that light is the most limiting resource for tree basal area growth and that reduced competition for light can be explained to some degree by complementarity in light use to increase tree growth in mixed forests.
This thesis thus described the productivity patterns when mixing tree species and explored possible mechanisms of higher productivity in mixed stands compared with monoculture stands in the Netherlands. Complementary use of aboveground and belowground resources probably contributes to the higher productivity in mixed stands, but other factors including pathogens, nutrient cycling and litter decomposition were not addressed but cannot be excluded. Overyielding in Douglas-fir–beech and pine–oak mixtures was maintained over time, probably owing to the intensive thinning in Dutch forests. The results shed new light on the stress-gradient and resource-ratio hypotheses. For mixtures in Dutch forest, the greatest productivity gain in Douglas-fir–beech and pine–oak mixtures was achieved on the poorer soils, and it was argued that this is at least partially driven by complementary use of light, while the role of complementarity in use of soil resources is more obscure. Overall, this thesis suggest a substantial potential of species mixing for increasing productivity, which may run in parallel with enhancing other ecosystem services such as conservation of diversity and other nature values. Yet, more experimental studies on productivity in mixed stands are required to better unravel alternative mechanisms. Such understanding is required to manage the forests effectively in a century of unpreceded human driven changes in environmental conditions.
|Terug naar het lindewoud : strooiselkwaliteit als basis voor ecologisch bosbeheer
Hommel, P.W.F.M. ; Waal, R.W. de; Muys, B. ; Ouden, J. den; Spek, T. - \ 2007
Zeist : KNVV Uitgeverij - ISBN 9789050112666 - 72
bosecologie - bossen - houtteelt - gemengde bossen - soortenkeuze - herstel - bosstrooisel - kwaliteit - nederland - geïntegreerd bosbeheer - ecologisch herstel - forest ecology - forests - silviculture - mixed forests - choice of species - rehabilitation - forest litter - quality - netherlands - integrated forest management - ecological restoration
Het boek 'Terug naar het lindewoud' laat zien hoe met weinig moeite de ondergroei van Nederlandse bossen verbeterd kan worden door het aanplanten van inheemse boomsoorten met een snel afbreekbare strooisellaag. Het boek 'De natuur als bongenoot - De wereld van Heimans en Thijsse in historisch perspectief' beschrijft de ontwikkeling van de natuurbescherming van 1845 tot 2005
Effecten van variabele dunning; een beschouwing aan de hand van literatuur, modelresultaten, praktijkvoorbeelden en expertjudgement
Olsthoorn, A.F.M. ; Berg, C.A. van den; Kramer, K. ; Oosterbaan, A. ; Raffe, J.K. van - \ 2005
Wageningen : Alterra (Alterra-rapport 1318) - 63
dunnen - houtteelt - kosten - simulatiemodellen - mechanisatie - impact - gemengde bossen - nederland - bosbedrijfsvoering - thinning - silviculture - costs - simulation models - mechanization - impact - mixed forests - netherlands - forest management
In dit project is de kennis die in Nederland beschikbaar is over variabel dunnen op een rij gezet. Daarbij is gebruik gemaakt van literatuur, praktijkvoorbeelden, modellen en expert kennis. De methode wordt nog maar kort toegepast, dus de resultaten van en simulatiemodel en expert kennis waren belangrijk om te kunnen speculeren over de lange termijn effecten (met een aantal aannamen). Met deze uitkomsten konden ook kosten en opbrengsten van variabel dunnen op een rij gezet worden. Variabel dunnen kan de functievervulling van een opstand beïnvloeden, met een maximaal te verwachten effect als de intensiteit van de ingreep op dezelfde plekken in de opstand wordt herhaald
Beheerscenario's voor gemengde bossen; deel 1: methodiekontwikkeling
Oosterbaan, A. ; Bartelink, H.H. ; Olsthoorn, A.F.M. ; Wijdeven, S.M.J. - \ 2002
Wageningen : Alterra (Alterra-rapport 495) - 28
gemengde bossen - bosbedrijfsvoering - methodologie - indicatoren - meervoudig gebruik - nederland - belevingswaarde - bosbeheer - bosbouw - houtproductie - natuurwaarde - mixed forests - forest management - methodology - indicators - multiple use - netherlands
In 2001 is gewerkt aan een methodiek om in een relatief kort tijdsbestek in te schatten hoe de functievervulling van een bepaald gemengd bostype zal verlopen bij een bepaald beheerscenario. Hiervoor worden opstanden van verschillende leeftijdsfasen gezocht die passen binnen het desbetreffende beheerscenario. Van deze opstanden wordt aan de hand van een stel meetbare indicatoren de natuurwaarde, de productiewaarde en de belevingswaarde bepaald, zodat deze in de tijd uitgezet kunnen worden.
Groei van ongelijkjarige mengingen van grove den en berk op arme zandgronden; resultaten van metingen in 22 opstanden op de Veluwe en de Sallandse Heuvelrug
Wijdeven, S.M.J. ; Oosterbaan, A. ; Berg, C. v.d.; Jole, M. van - \ 2000
Wageningen : Alterra (Alterra-rapport 14) - 33
pinus sylvestris - betula - bosecologie - gemengde bossen - verjonging - nederland - gemengde opstanden - ongelijkjarige opstanden - veluwe - overijssel - salland - pinus sylvestris - betula - forest ecology - mixed forests - regeneration - netherlands - mixed stands - uneven-aged stands - veluwe - overijssel - salland
Het voorkomen en de groei van berk in ongelijkjarige mengingen van grove den en berk is bepaald op basis van opstandgemiddelden. Er is geen duidelijk verband tussen het voorkomen en de groei van berk en de schermdichtheid van grove den. Actuele groeigegevens zijn noodzakelijk voor een nadere detaillering. Berk kan onder een breed scala van condities voorkomen; sturen van berk is dan ook moeilijk. De onderzochte mengingen vertonen een hogere productiviteit dan monoculturen. Door de vele mogelijke interacties in gemengde bossen is het gebruik van modellen in het onderzoek noodzakelijk. Gerichte studies naar de actuele groei in relatie tot omgevingsfactoren zijn hiervoor onontbeerlijk.
Subantarctic forest ecology : case study of a conifer-broadleaved stand in Patagonia, Argentina
Dezzotti, A. - \ 2000
Agricultural University. Promotor(en): R.A.A. Oldeman; L.A. Sancholuz. - S.l. : S.n. - ISBN 9789058082169 - 140
bosbouw - ecologie - bosecologie - naaldbossen - loofhout - gemengde bossen - populaties - opstandsstructuur - gebieden - seksuele dimorfie - forestry - ecology - forest ecology - coniferous forests - broadleaves - mixed forests - populations - stand structure - areas - sexual dimorphism
In the temperate rainforests of southern South America, the tree genus Nothofagus (Nothofagaceae) is the dominant in extension and abundance on zonal soils at different latitudes and altitudes, as well as on intrazonal (e.g., wetlands) and azonal soils (e.g., morrenic and fluvioglacial deposits). Although concern on the global role of this biome is currently important, the existing level of ecological knowledge on its functioning is still inadequate to design a sound management to maintain or enhance forest values, services, and commodities. Vegetation misuse triggers severe biota and physical deterioration, particularly in the intrinsically fragile Andean Patagonic region characterised by seasonality of high rainfall levels, low temperature, strong intensity and frequency of winds, and extensive and deep mountain slopes. In Argentina, at low and mid elevations between 38° and 43°S and the annual isohyets of 1,500 to 2,000mm, the forest is composed of the xeric cypress Austrocedrus chilensis ("ciprés", Cupressaceae) and the mesic southern beech Nothofagus dombeyi ("coihue"). The effect of the strong east - west environmental gradient, caused by the Andes' rain shadow, on community composition and dynamics is striking. This is reflected in a clear vegetational zonation, whose edges are the sparse A.chilensis woodland surrounded by the Patagonian steppe towards the east and the Valdivian rainforest co-dominated by N.dombeyi towards the west. Both communities are separated only by tens of kilometres. The conifer-angiosperm association, characterised by two groups of plants with contrasting evolutionary histories and ecological adaptations, has received little scientific attention.
At 41°11'S and 71°25'W, a mixed, virgin, post-fire stand, located on a dry north-facing slope was examined regarding regeneration, size, age, and spatial structures, and stand and tree growth. Inferences on community dynamics were made. The minimum area of the community was also estimated. Density, basal area, and volume of adult trees is calculated in 658 ind ha -1(66.6% of A.chilensis ), 72.1 m 2ha -1(65.6%), and 608.7m 3ha -1(51.2%), respectively. Total density of saplings and seedlings is 2,991 (27.1% of A.chilensis ) and 7,143 ind ha -1(34.3%), respectively. Stand growth is estimated in 7.3m 3ha -1yr -1(42.5% of A.chilensis ) and 3.7 t ha -1yr -1(32.4%). Between species, individual increments significantly differ within development stages. Adults A.chilensis and N.dombeyi grow in diameter at an individual rate of 0.36 and 0.57cm yr -1, respectively, while in height at a rate of 15.8 and 29.3cm yr -1, respectively. Saplings of A.chilensis and N.dombeyi grow in diameter at a rate of 0.11 and 0.21cm yr -1, respectively, while in height at a rate of 7.8 and 17.2cm yr -1, respectively. Within species, adults grow in diameter at rates between 2.7 (in N.dombeyi ) and 3.2 (in A.chilensis ) times significantly faster than their respective saplings, and also old trees show significantly larger diameter increments than young trees. Within species, adults grow in height at rates between 0 (in N.dombeyi ) - 2.0 (in A.chilensis ) times faster than their respective saplings. In A.chilensis , old trees grow in height at significantly higher rates than young trees, whereas this is not the case for N.dombeyi . For each A.chilensis tree, a negative relationship is found between individual diameter (range= 0.22 to 0.42cm yr -1) and height growth (12 to 21cm yr -1), and the number of neighbour trees (0 to > = 7) taller than itself within a 5m distance. Contrarily, for N.dombeyi no relationship is observed between these variables. In A.chilensis , individual growth rates do not differ significantly between sex classes: for males, mean and current diameter, and height growth rate is 0.360, 0.132, and 17.6cm yr -1, respectively, while for females is 0.348, 0.124, and 17.2cm yr -1, respectively.
The inherently inferior growth capacity of A.chilensis over N.dombeyi is explained by its lower leaf photosynthetic rate. Conifers from the northern hemisphere show a primary productivity similar to their mostly associated deciduous angiosperms. However, southern hemisphere conifers show a lower productivity than broadleaved. This is probably because they cannot benefit differentially from an extended period of net photosynthesis as they co-exist mainly with broadleaved evergreen species. The greater growth disadvantage of A.chilensis in comparison to N.dombeyi during the juvenile stage is consistent with the same trend observed in gymnosperms as a group: seedling represents the ontogenetic phase of slowest growing, caused by multiple factors related to leaf productivity and carbohydrate allocation. This constraint has been used to explain the decline and retreat of gymnosperms along evolutionary scales. Within species, the dependence of growth to age and crowding is indicative of one-sided, asymmetric competition for light: trees that arrived earlier to the site have pre-empt resources, developed a larger size, and therefore at present they interfere asymmetrically with those arriving later. However, contrasting responses are found according to species and growth variables: i) In N.dombeyi , the independence of individual growth to crowding, and of height growth to age/development stage of trees suggests that this species is rather insensitive to this competition type. On the contrary, A.chilensis is highly susceptible judging from the dependence between growth to age and taller neighbours. ii) In comparison to diameter growth, height growth differs slightly between age classes/stages, which reflect the common priority that trees give to height during development. Lack of gender-related growth differences in the dioecious A.chilensis would be masked by the low reproductive development exhibited in the sampled individuals. If trees in structurally well-developed stand are unable to express the reproductive potential as observed in isolated trees, then its incidence on the individual energetic budget would be marginal and marked intersexual growth contrasts would not be expected. This hypothesis would explain the incongruence with previously results suggesting a trade-off between vegetative and reproductive investments, and needs to be tested during future studies given the ecological and silvicultural relevance of this issue.
In 1860, both tree species began to colonize a heterogeneous site, following a fire that eliminated the original vegetation. This first regenerative pulse lasted 60 to 70 years after which recruitment ceased probably in response to canopy closure, resulting in the present even-aged clustered adult tree populations. Because of its lower density and higher growth rates, N.dombeyi constitutes widely spaced, big emergent trees of the stand. The build-up of the A.chilensis -dominated mixed stand probably improved autogenously local moisture conditions, encouraging establishment of N.dombeyi seedlings and defining a second continuous regenerative pulse starting ca.1930. In the understorey, the sapling population dominated by N.dombeyi represents a third regenerative pulse with ages between 1 to 10 years. The current-day stand structure is represented by a young population dominated primarily by N.dombeyi , and a mature overstorey dominated primarily by A.chilensis . In absence of large-scale impacts, changes in forest structure over time would be accounted for interspecific differences in recruitment, growth rate, and sensitivity to competition, probably resulting in a local decline of the conifer component. However, the combination of a great longevity and a light-demanding temperament of A.chilensis implies that frequent to very infrequent large-scale impacts would be sufficient to maintain its abundance in the landscape. These results, together with others described in literature, suggest that divergent development patterns occur in the A.chilensis - N.dombeyi stands, probably because these forests grow under a spatially varied environment and their responses differ consequently.
Based on the concept of "quantitative minimum area", the statistically optimum plot size for the ecological study of a temperate forest was examined. Changes in the estimated tree density (N), basal area (G), stemwood volume (V), and volume growth rate (I v ) per area unit, in relation to the increase of sample plot size (X), were analysed. Means of N, G, V, and I v fluctuated considerably within a range of small plot sizes, showing stability at X >= 1,000m 2. The accuracy of the parameters estimates measured as relative error (RE) increases as long as the plot size is enlarged. For X= 1,000m 2, ER varies between ± 30% and ± 49%, and for X= 2,500m 2, RE varies between ± 20% and ± 32%. Around X= 5,000m 2should be sampled to obtain RE < = ± 20% in all variables, according to the developed regressions RE= f (X) (P<0.05). This estimated plot size is larger than those often recommended in literature for ecological studies of temperate forests.
|Management of mixed-species forest: silviculture and economics
Olsthoorn, A.F.M. ; Bartelink, H.H. ; Gardiner, J.J. ; Pretzsch, H. ; Hekhuis, H.J. ; Franc, A. - \ 1999
Wageningen : IBN-DLO - ISBN 9789076095080 - 389
gemengde bossen - bosbedrijfsvoering - houtteelt - shelterwoodsysteem - bosbouweconomie - bosbeleid - europa - conferenties - dauerwald - mixed forests - forest management - silviculture - shelterwood system - forest economics - forest policy - europe - conferences - dauerwald
Omvorming van fijnspar in de beheereenheid Staphorst
Koop, H.G.J.M. ; Oosterbaan, A. ; Wieman, E.A.P. - \ 1998
Nederlands Bosbouwtijdschrift 70 (1998)5. - ISSN 0028-2057 - p. 235 - 238.
bosbouw - houtteelt conversie - bosbedrijfsvoering - gemengde bossen - monocultuur - picea abies - nederland - overijssel - forestry - silvicultural conversion - forest management - mixed forests - monoculture - picea abies - netherlands - overijssel
Groei en concurrentie in gemengd bos: een modelmatige analyse in Douglas/beukopstanden.
Bartelink, H.H. - \ 1998
Nederlands Bosbouwtijdschrift 70 (1998)5. - ISSN 0028-2057 - p. 215 - 219.
gemengde bossen - concurrentie tussen planten - pseudotsuga menziesii - fagus sylvatica - mixed forests - plant competition - pseudotsuga menziesii - fagus sylvatica
Simulation of growth and competition in mixed stands of Douglas-fir and beech
Bartelink, H.H. - \ 1998
Agricultural University. Promotor(en): J. Goudriaan; A. van Maaren; G.M.J. Mohren. - S.l. : Bartelink - ISBN 9789054858348 - 222
bosbouw - gemengde bossen - groeimodellen - houtaanwas - voorspellen - plantensuccessie - periodiciteit - vegetatie - bomen - computersimulatie - simulatie - simulatiemodellen - pseudotsuga menziesii - fagus sylvatica - gemengde opstanden - forestry - mixed forests - growth models - increment - forecasting - plant succession - periodicity - vegetation - trees - computer simulation - simulation - simulation models - pseudotsuga menziesii - fagus sylvatica - mixed stands
For a long time, the emphasis in silviculture in Western Europe was solely on even-aged, monospecific stands; many empirical stand-level growth models were developed and successfully used for managing such stands. In contrast, no generally accepted growth and yield approach has emerged so far for mixed forests. Moreover, the inexhaustible number of species combinations, management regimes, and site-dependent interactions make an empirical approach less suitable.
In the present study, a mechanistic model was developed that simulates growth and yield in mixed forest stands. Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) and beech ( Fagus sylvatica L.) were used in this research. In the model, tree growth is dependent on radiation availability. Stand development is largely driven by competition for radiation. A spatial module was developed to investigate the effects of tree and stand characteristics on radiation interception. The study showed that in heterogeneous stands a spatial approach is needed to account for competition between trees.
Growth of the trees was estimated using the radiation-use efficiency concept (RUE). Results revealed that detailed process models can be used to estimate RUE and that it is a suitable tool for (mixed) forest modelling.
To describe the distribution of the dry matter growth, a separate module was developed using functional relationships between tree components: the dry matter distribution is driven by the aim to maintain structural balances within the tree. The study showed that this approach is able to reproduce the development of an individual forest tree. The approach was thus considered very suitable for modelling the effects of between-tree competition for resources on growth and development of mixed forest stands.
The overall growth model, COMMIX, was applied to investigate the effects of stand composition on mixed stand productivity, using a replacement series. Analysis showed that the productivity of mixed forest stands is generally somewhere in between the yield levels of the monocultures of the less productive and the most productive species. It will only be possible to achieve higher yields in mixed stands if these stands have a relatively small proportion of the sub-dominant species. In the case of Douglas-fir and beech, the maintenance of a mixed stand appeared to conflict with the maximization of the wood production.
Insufficient data are available on mixed stands to directly support decision taking in forest management. New research tools capable of providing forest managers with information on possible management scenarios and on the consequences of certain management regimes are therefore urgently required. The present modelling approach is part of an ongoing development of models for mixed stands. The infinite variety of possible species mixtures coupled with the range of environmental conditions under which mixtures might be grown, necessitates a mechanistic approach and emphasises the potential use of such models.
Omvorming van monoculturen van douglas naar gemengd bos via natuurlijke verjonging
Oosterbaan, A. - \ 1996
Nederlands Bosbouwtijdschrift 68 (1996)2. - ISSN 0028-2057 - p. 61 - 64.
bosbouw - gemengde bossen - verjonging - nederland - gemengde opstanden - forestry - mixed forests - regeneration - netherlands - mixed stands
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
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
Simulatie van spontane bosontwikkeling.
Bartelink, H.H. ; Hees, A.F.M. van - \ 1991
Nederlands Bosbouwtijdschrift 63 (1991). - ISSN 0028-2057 - p. 66 - 74.
bosbouw - natuurlijke verjonging - plantensuccessie - periodiciteit - vegetatie - computersimulatie - simulatie - simulatiemodellen - gemengde bossen - gemengde opstanden - forestry - natural regeneration - plant succession - periodicity - vegetation - computer simulation - simulation - simulation models - mixed forests - mixed stands
|Monoculture versus mixture : interactions between susceptible and resistant trees in a mixed stand
Heybroek, H.M. - \ 1982
Wageningen : De Dorschkamp (Mededeling / Rijksinstituut voor Onderzoek in de Bos- en Landschapsbouw "De Dorschkamp" nr. 199)
bosbouw - hybriden - gemengde bossen - monocultuur - boomveredeling - proeven - gemengde opstanden - forestry - hybrids - mixed forests - monoculture - tree breeding - trials - mixed stands
|Onderzoek naar de mogelijkheden van de aanleg van gemengd loofhoutbos
Tideman, H.C. - \ 1977
Wageningen : De Dorschkamp (Rapport / Rijksinstituut voor onderzoek in de bos- en landschapsbouw "De Dorschkamp" no. 104) - 47
bosbouw - gemengde bossen - houtteelt - bosbouwkundige handelingen - groei - milieufactoren - nederland - gemengde opstanden - zuid-holland - forestry - mixed forests - silviculture - forestry practices - growth - environmental factors - netherlands - mixed stands - zuid-holland
Zur soziologie und Synoekologie der Buchen- und Buchenmischwaelder der nordwestdeutschen Mittelgebirge
Diemont, W.H. - \ 1938
Wageningen University. Promotor(en): J. Jeswiet. - Hannover : Floristisch-soziologischen Arbeitsgemeinschaft in Niedersachsen - 182
bosbouw - bomen - loofverliezende bossen - gebergten - duitsland - synecologie - gemengde bossen - bondsrepubliek duitsland - fagus sylvatica - gemengde opstanden - forestry - trees - deciduous forests - mountains - germany - synecology - mixed forests - german federal republic - fagus sylvatica - mixed stands - cum laude
The beech (Fagus sylvatica L.) occurs in Europe in pure and mixed mesophile, deciduous, dominantly broad-leaved forests belonging to the phytosociological order of the Fagetalia silvaticae. This order includes the true beech forests united into the Fagion alliance and is represented in the area considered by the Fagetum boreoatlanticum (with 5 subassociations), and the mixed beech forests belonging to the Fraxino-Carpinion and represented by the Querceto-Carpinetum medioeuropaeum (with 2 subassociations). A further subdivision into variants and subvariants was made.Some of the subassociations only occur on soils with a high watertable; others represent ultimate equilibrium stages in vegetational development under normal conditions, called climax vegetation types. Diemont concluded from his investigations that the climax types varied with the soil; nevertheless, within one climatic region, they were so much alike to be considered members of one climax swarm ('Klimaxschwarm'). However distinct differences between the floristic composition on northern or eastern slopes and on other slopes were found; within one region such types may be combined into one climax group ('Klimaxgruppe').Physical and chemical soil analysis supported the botanical classification. Climatic data were added. Some notes were included on the ephemeral vegetation occurring after removal of the forest.The natural forest types and the ecological conditions under which they occurred supplied valuable information on the most suitable tree and shrub species for reforestation and the treatment of the forest.