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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    Use of integrated modelling for experimental design; final report
    Kabat, P. ; Dolman, A.J. ; Ashby, M. ; Gash, J.C. ; Wright, I. ; Culf, A. ; Calvet, J.C. ; Delire, C. ; Noilhan, J. ; Jochum, A. ; Silva Dias, M.A. ; Fisch, G.A. ; Santos Alvala, R.C. ; Nobre, C.A. ; Prince, S.D. ; Steininger, M. - \ 1999
    Wageningen : DLO-Staring Centre - 210
    tropische regenbossen - microklimaat - vegetatie - atmosfeer - evaporatie - modellen - amazonas - brazilië - tropical rain forests - microclimate - vegetation - atmosphere - evaporation - models - amazonas - brazil
    Remote sensing monitoring system for sustainable forest management and land cover change in Indonesia
    Hoekman, D.H. ; Varekamp, C. ; Jong, J.J. de; Valkengoed, E.H. van; Vissers, M.A.M. ; Wooding, M.G. - \ 1999
    Delft : Netherlands Remote Sensing Board (BCRS) - ISBN 9789054112730 - 77
    tropische regenbossen - landgebruik - monitoring - remote sensing - indonesië - tropical rain forests - land use - monitoring - remote sensing - indonesia
    Radar for rain forest : a monitoring system for land cover change in the Colombian Amazon
    Bijker, W. - \ 1997
    Agricultural University. Promotor(en): R.A. Feddes; W. van Wijngaarden; D.H. Hoekman. - Enschede : ITC - ISBN 9789061641391 - 192
    remote sensing - radar - technieken - tropische regenbossen - vegetatie - bosbouw - luchtkarteringen - toepassingen - colombia - remote sensing - radar - techniques - tropical rain forests - vegetation - forestry - aerial surveys - applications - colombia
    Radar remote sensing to support tropical forest management
    Sanden, J.J. van der - \ 1997
    Agricultural University. Promotor(en): R.A. Feddes; R.A.A. Oldeman; D.H. Hoekman. - S.l. : S.n. - ISBN 9789054857785 - 330
    bosbouw - remote sensing - luchtkarteringen - tropen - bosbedrijfsvoering - planning - tropische regenbossen - vegetatie - toepassingen - forestry - remote sensing - aerial surveys - tropics - forest management - planning - tropical rain forests - vegetation - applications

    This text describes an investigation into the potential of radar remote sensing for application to tropical forest management. The information content of various radar images is compared and assessed with regard to the information requirements of parties involved in tropical forest management at the global, national and local spatial levels. The study distinguishes between the use of radar remote sensing for application to forest resource assessment and forest resource monitoring. Both assessment and monitoring are essential components of procedures for sustainable forest management. The radar data studied are of tropical forest areas near the township of Mabura Hill in Guyana and the city of San José del Guaviare in Colombia. Mabura Hill is comprised of differing intact, primary forest types and forests that have been subjected to industrial selective logging. San José del Guaviare, on the other hand, is characterised by the presence of secondary forests and a variety of non-forest cover types. The available radar data set includes high resolution airborne radar images with differing wavelengths (i.e. X-, C-, L- and P-band) and polarizations, time-series images acquired by the first European remote sensing satellite ERS-1 and a collection of low altitude, nadir-looking, X-band scatterometer measurements.

    The study makes use of three fundamentally different information sources from the radar return signal: its strength or backscatter, polarization and phase, and spatial variability or texture. Results show that backscatter values computed from L- and P-band radar data and textural attributes computed from high resolution X- and C-band radar data make modest to good and complementary bases for region-based classification of tropical land cover at the level of primary forest types. Textural attributes and backscatter values computed per region from mono-temporal ERS-1 images make modest bases for classifying at the levels of primary forest, logged-over forest, secondary forest and non- forest and poor bases for classifying at the level of primary forest types. Roads are usually the most easily observable indicators of foregoing and/or forthcoming (selective) logging and other human activities in ERS-1 images. Detection of change in road networks by means of ERS-1 images would make a good first step in forest resource monitoring at the national spatial level, in particular. Textural attributes enable the ranking of forest types according to the degree of canopy roughness. Specific textural attributes also allow for quantification of canopy architectural properties. Despite differences in measurement scale, the canopy roughness of the land cover types studied was found to appear similarly in the texture of the available spaceborne and short wavelength airborne radar images.

    Trees and light : tree development and morphology in relation to light availability in a tropical rain forest in French Guiana
    Sterck, F.J. - \ 1997
    Agricultural University. Promotor(en): H.H.T. Prins; F.J.J.M. Bongers. - S.l. : Sterck - ISBN 9789054856733 - 122
    bosbouw - habitus - levensvorm - plantenontwikkeling - plantenecologie - licht - plantenmorfologie - tropische regenbossen - vegetatie - tropen - frans-guyana - natuurlijke opstanden - forestry - habit - life form - plant development - plant ecology - light - plant morphology - tropical rain forests - vegetation - tropics - french guiana - natural stands

    Tropical rain forest trees spend their life in a heterogeneous light environment. During their life history, they may change their growth in relation to different levels of light availability. Some of their physiological processes (e.g. photosynthesis, carbon allocation, and meristern activity) change with light availability, and tune their development and morphology to the ambient light levels. The underlying physiological processes are not investigated in the present study. The focus is on the development and morphology of trees of canopy species in relation to the light availability in tropical rain forest. The possible consequences for survival, growth, and reproduction of trees are not assessed directly, but are discussed on a speculative basis.

    The relationships between the light environment, tree development, and morphology are investigated for trees of different size, ranging from small saplings to trees of adult stage. Trees of increasing size are compared in order to explore the changes in tree development and morphology, and their relation to the light environment, with ontogeny. Ontogeny is referred to as the overall growth and development pattern during tree life, both for individual trees and (in more general) for a given tree species.

    The field work for this thesis was carried out in French Guiana. This country in the north-east of South America has an area of 83.000 km 2and is covered by evergreen tropical rain forest. The field work was conducted at two biological stations. 'The Piste St. Elie' station is located 30 km from the coast, south of the town of Sinnamary, and the biological station 'Les Nouragues' is located 100 km from the coast, south of Cayenne. Two canopy tree species were selected for this study: Dicorynia guianensis Amshoff. (Caesalpiniaceae) and Vouacapoua americana Aubl. (Caesalpiniaceae). Both are common species in the forests of French Guiana, and are considered late successionals or shadetolerant species (Schulz 1960). In some chapters, these species are compared with an early successional (light demanding) species, Goupia glabra Aubl. (Celastraceae). Trees of these three species are harvested for their timber in French Guiana and its surrounding countries.

    The trees that were shorter than 20 rn had not yet reached the open upper canopy. These trees usually occur at relatively low light levels. Although these trees may differ in height (from 0 to 20 m), they usually show the same type of growth response to ambient light levels. They produced more growth units and more leaves at higher light availability. They thus increased their total leaf area and leaf area index (LAI, a measure for the number of leaf layers in the crown) as a response to higher light levels. Under persisting high light levels, the increase in total leaf area may enable these trees to fix more carbohydrates (i.e. carbon) for successful growth and survival in the future. Trees with a high LAI at higher light availability, in combination with more columnar shaped crowns, achieve net photosynthesis (more carbon intake than consumption by leaves) at the least possible cost for leaf area support. In contrast, trees with more planar crowns and lower LAI at lower light availability may avoid self-shading of leaves, but risk higher costs for leaf area support.

    Trees also produced shorter growth units at lower light availability, and thus spaced their leaves at shorter distances than trees at higher light availability. In more closely spaced leaves, the investments for the support of one leaf are lower. As leaf size did not change in relation to light availability, trees displayed their leaf area more economically (at lower carbon costs) at lower light availability. In this way, they increased light interception per unit of fixed carbon, and they may thus be better able to survive the shade.

    Dicorynia and Vouacapoua trees also grew faster in height with increasing light availability. In general, trees may reduce their height growth because low light levels simply limit growth. At low light levels, trees are shaded by taller neighbouring trees which intercept the majority of light above them, but they may survive for some time by producing their leaf area slowly and efficiently. When light levels increase because one (or more) of the taller neighbours falls down, trees start to increase their height growth, and may compete with their neighbours for newly available light and space. For both species studied, it was shown that height growth further increased at very high light levels in large gaps through preferential growth of the leader (axis which supports the uppermost apical meristern of the crown) over the other axes in the crown. At lower light levels, individuals did not show preferential growth of the leader. Thus, height growth increased not only because the higher light levels are less growth limiting, but also because of preferential growth of the leader.

    These growth responses to light refer to trees (up to 20 m tall) that were still heading for the canopy. The taller trees (heights of sampled trees range between 26 and 37 m) at higher light availability in the upper canopy had a larger total leaf area and total branch length than the trees shorter than 20 m. These taller trees also produced larger and more planar shaped crowns, did not further increase their LAI, and decreased their leader growth and the space between leaves, as compared with the smaller individuals. The shift to a wider crown is probably caused by increasing light (and space) availability, and may constrain a further increase in the LAI (the leaves occurred over a much larger horizontal area). The lower leader growth and the production of leaves at shorter distances indicate that these taller trees changed from investments in vertical expansion to investments in the replacement of leaves (and flowers).

    The increasing stature with ontogeny has to be balanced by mechanical strength (thickness). This strength is needed to carry the increasing tree weight and to resist wind stress. The mechanical design expresses the balance between overall tree stature (in terms of weight or wind force experienced by the tree) and tree (mechanical) strength. The changes in mechanical design with ontogeny were investigated for Goupia, Dicorynia, and Vouacapoua using two models. (1) The elastic-stability model emphasises the mechanical strength against its own weight. Using this model, it was shown that trees of the study species decreased their 'safety margins' (strength) early in ontogeny, but increased their margins of safety later. Trees had their lowest margins at a stem diameter of 15 to 25 em. These margins were close to the theoretical minimum, i.e. trees would buckle under their own weight if they were slightly more slenderly built (taller at a given diameter). In comparison with some temperate tree species, the trees of the present study appeared to have lower safety margins because they were more slender. Slenderness (height/diameter ratio), however, is only one of the factors determining the strength of a tree. The denser and stiffer wood of tropical trees may increase the mechanical strength of tropical trees in comparison with temperate trees. Another explanation for the lower safety margins of tropical trees is that they are exposed to lower external stress forms than temperate trees. Temperate trees experience heavy storms and snow loads during their life, whereas the trees of the present study do not experience such forms of stress. (2) The constant-stress model emphasises the mechanical strength over wind stress on the tree. For the species of study, it was shown that the safety margins against wind stress increased with ontogeny. This was in line with the expectations, because wind stress is likely to increase with increasing tree stature. Finally, the influence of light availability on mechanical tree design could not be investigated. The trees studied had long life-histories under unknown light conditions, and therefore did not show a significant response within the 2-3 years of investigation.

    The ecological knowledge on commercial tree species presented in this work is thought to be useful for the fine tuning and improvement of forest management systems. In these systems, canopy gaps of different size are created, and they may affect the growth of trees. The results of this thesis indicate that manipulations of light availability (either by killing dominant trees thus inducing light level increase, or by shading) in forests may increase the timber production in trees. Besides this, the follow-up to this study may provi de morphological traits that can be used to indicate the growth potential of trees in relation to the light environment. It is suggested that there is a need for knowledge on the growth response of trees (both in terms of timber production, morphology and development) to the whole range of light availability. Manipulations of the light environment may then be tuned to individual trees of commercial species in order to approach the light conditions that provoke the desired growth response. In general, fundamental research on tree growth in a natural habitat, extended by research on tree growth at higher light levels outside the natural habitat, may provide valuable insights for the improvement of forest management systems.

    Radar remote sensing of tropical rain forests: the AIRSAR-93 campaign in Guyana and Colombia.
    Hoekman, D.H. ; Sanden, J.J. van der; Bijker, W. - \ 1996
    Delft : BCRS - ISBN 9789054111870 - 59
    bosbouw - remote sensing - luchtkarteringen - tropische regenbossen - vegetatie - toepassingen - guyana - colombia - forestry - remote sensing - aerial surveys - tropical rain forests - vegetation - applications - guyana - colombia
    Radar remote sensing of tropical rain forests: ERS-1 studies in Guyana and Colombia. Final Report.
    Sanden, J.J. van der; Hoekman, D.H. ; Bijker, W. - \ 1996
    Delft : BCRS - ISBN 9789054111962 - 43
    bosbouw - remote sensing - luchtkarteringen - tropische regenbossen - vegetatie - toepassingen - guyana - colombia - forestry - remote sensing - aerial surveys - tropical rain forests - vegetation - applications - guyana - colombia
    Radar remote sensing of tropical rain forests: the SAREX-92 campaign in Guyana and Colombia.
    Hoekman, D.H. ; Sanden, J.J. van der; Bijker, W. - \ 1994
    Delft : BCRS - ISBN 9789054111160 - 68
    bosbouw - remote sensing - luchtkarteringen - toepassingen - tropische regenbossen - vegetatie - guyana - colombia - forestry - remote sensing - aerial surveys - applications - tropical rain forests - vegetation - guyana - colombia
    Sistema CELOS de manejo. Manual preliminar.
    Bodegom, A.J. van; Graaf, N.R. de - \ 1994
    In: Werkdocument IKC natuurbeheer nr. 65. IKC/NBLF (1994) 58 pp
    kroondak - kroon - bosbedrijfsvoering - bosbouw - handleidingen - natuurlijke verjonging - planning - bomen - tropische regenbossen - tropen - vegetatie - oerbossen - werkplannen - oude bossen - canopy - crown - forest management - forestry - guide books - natural regeneration - planning - trees - tropical rain forests - tropics - vegetation - virgin forests - working plans - old-growth forests
    Modeling nutrient and moisture cycling in tropical forests.
    Noij, I.G.A.M. ; Janssen, B.H. ; Wesselink, L.G. ; Grinsven, J.J.M. van - \ 1993
    Wageningen : Tropenbos Foundation (Tropenbos series 4) - ISBN 9789051130164 - 195
    bosbouw - oerbossen - tropische regenbossen - vegetatie - tropen - bodemvruchtbaarheid - bodemchemie - anorganische verbindingen - mineralen - boekhouding - bodemwater - permeabiliteit - absorptie - hygroscopiciteit - modellen - onderzoek - computersimulatie - simulatie - simulatiemodellen - oude bossen - forestry - virgin forests - tropical rain forests - vegetation - tropics - soil fertility - soil chemistry - inorganic compounds - minerals - accounting - soil water - permeability - absorption - hygroscopicity - models - research - computer simulation - simulation - simulation models - old-growth forests
    Gross inputs and outputs of nutrients in undisurbed forest, Tai Area, Cote d'Ivoire.
    Stoorvogel, J.J. - \ 1993
    Wageningen : Tropenbos Foundation (Tropenbos series 5) - ISBN 9789051130171 - 148
    ivoorkust - bosbouw - landschap - landschapsbescherming - nationale parken - bescherming - bodemchemie - bodemvruchtbaarheid - bodemwater - tropische regenbossen - vegetatie - oerbossen - oude bossen - cote d'ivoire - forestry - landscape - landscape conservation - national parks - protection - soil chemistry - soil fertility - soil water - tropical rain forests - vegetation - virgin forests - old-growth forests
    Forest gradients in West Africa : a spatial gradient analysis
    Rompaey, R.S.A.R. van - \ 1993
    Agricultural University. Promotor(en): R.A.A. Oldeman. - S.l. : Van Rompaey - ISBN 9789054851202 - 142
    bosbouw - oerbossen - tropische regenbossen - vegetatie - tropen - west-afrika - plantenecologie - liberia - ivoorkust - oude bossen - forestry - virgin forests - tropical rain forests - vegetation - tropics - west africa - plant ecology - liberia - cote d'ivoire - old-growth forests
    The tropical rain forests of West Africa, west of the Dahomey interval, once covered some 40 million ha. Being on the western fringe of the African continent, they receive abundant rainfall from the SW monsoon. Further inland, rainfall gradually decreases and the forests give way to savanna and ultimately to the Sahara desert.

    This Upper Guinea forest block used to cover most of Liberia and parts of Côte d'Ivoire and Ghana. Here, deforestation rates are among the fastest in the world. Humans have reduced the forest cover by some 80 %. Most of the forest has been converted to agricultural land. Fire and heavy timber mining have left the remaining forest in a poor state. Sustainable forest management has not yet been attained. A key prerequisite for achieving such management is more and better knowledge of the ecology of these complex and highly diverse ecosystems and of their species.

    Gradients are gradual changes in space e.g. of species composition in the ecosystems. In this book forest gradients are studied at two levels of scale: the regional forest gradient from the coast to the forest- savanna boundary, and local gradients along slopes in the landscape. The species composition of the large forest trees with a diameter exceeding 70 cm was studied; this entailed adapting the existing methods used in vegetation science to cope with these huge subjects. In West African forest exploitation 70 cm diameter is a common limit for selective cutting of trees.

    At the regional scale, the spatial gradient analysis consisted of a three-step approach: 1. ordination of forest areas and species; 2. spatial interpolation of the ordination scores of the forest areas; 3. relating spatial trends in species composition to trends in rainfall and patterns in lithology and relief.

    Tree species composition in a forest area was determined by using forest inventory data from the pre- logging era in SE Liberia and SW Côte d'lvoire. These data were ordinated together with data from three sample plots of 20 ha each established in Taï National Park. The old and new sample plots together covered 21 640 ha. Of the largest tree species, 53 were retained for the ordination.

    The forest gradient was mapped by interpolating lines of equal ordination scores and plotting these on the map. The ordination table allowed these ordination scores to be translated into the corresponding species composition. Each tree species has an individual position along the gradient, given by its ordination score. The ecological range of the species is indicated by the range of sample scores in which it occurred. The gradient map with isoscore lines provides a valid alternative to mapping by types or classes and overcomes the problem of transitional types.

    Over 400 km a pronounced regional forest gradient was found from the Liberian coast towards the forest- savanna boundary in Côte d'Ivoire. This gradient correlated well with the SW-oriented rainfall gradient. On part of the map the forest gradient showed an anomaly. The forests on a band of sericite-chlorite schist from Taï National Park towards the NE were ranked 'wetter' than expected from their position on the rainfall gradient. Apparently, the rainfall effect was compensated by the greater moisture content of the soils derived from sericite-chlorite schist. Furthermore, the rain shadow of Putu range (753 m above sea level) was reflected in the forest gradient by a zone of fast compositional change. These results are comparable with those of other studies on the regional forest gradients in Ghana, Côte d'Ivoire and Liberia.

    Forest gradients along slopes spanning a 20 to 40 m elevation interval were studied in Taï National Park in sample plots at three locations: near Zagné in the drier north-west (plot size 23 ha), near Taï in the middle (25 ha) and near Para in the wetter south-west of the Park (22 ha).
    All trees in these plots with a diameter larger than 70 cm were recorded and mapped. Swamp areas were excluded from these plots. A digital terrain model and a physiographic soil map were prepared for each site.

    The approach used for the analysis of the slope gradient contained the same elements as for the regional gradient, but in reverse order: 1. the soil survey revealed that the spatial trend in environmental variation was related to local elevation; 2. thus, contour samples of trees growing within an elevation interval were composed. A series of 11 or 12 consecutive intervals was calculated at each site in such a way that each sample covered 2 ha. 3. Tree species composition was determined per sample and all samples of the three sites were ordinated together using Detrended Correspondence Analysis (DCA). The sample scores on the first ordination axis were plotted against elevation to check the hypothesis of elevational gradients. Tree density, species richness, basal area and stem biomass per contour sample were analysed in a similar way for elevational trends.

    The contour sampling technique proved to be appropriate for the analysis of floristic slope gradients in large trees. The spatial autocorrelation of the contiguous samples is assumed to counterbalance the small number of trees per sample. The species order resulting from this ordination was similar to the one obtained in the regional gradient and hence, could be interpreted as a wet-dry axis. On the three sites species composition changed from "drier" species upsIope to "wetter" downslope. The lower slope on a drier site was similar in species composition to the upper slopes of its wetter neighbour. Thus, slope gradients are sliding gradients on the regional forest gradient. The regional gradient was related to rainfall and lithology. These factors are largely expressed in soil moisture availability. Hence, gradients in moisture availability probably explain the forest gradients along slopes.

    Tree density and species richness of the large trees decreased towards the wet end of the gradient, both between sites, e.g. from Zagné to Para, and within the Taï site, from upper slope to lower slope. This trend in species richness of the large trees contradicts one of the tenets of the Pleistocene forest refugia theory, namely that species richness increases towards the core area of a refugium. A Pleistocene refugium is hypothesized to have existed in the Grabo hills to the southwest of Taï National Park.

    Basal area curves showed a peak in middle slope positions and declined towards both the upper and lower end of the catena. A general trend of increasing wood density of the large tree species was found towards the wet end of the gradient.

    Some implications of the continuous variability model are evaluated as a scientific basis for forest management and conservation of biodiversity. At the regional scale, forest management should be adapted to the individual position of each forest area along the gradient. The tree species chosen and the forest land evaluation should both reflect this position. Catena plots are suggested as more appropriate for forest inventory than random sampling in areas with pronounced slope gradients.

    Any conceivable strategy for conservation of biodiversity in West Africa must aim at protecting forests along the entire gradient, because at any point along the gradient different species attain their optimum. A "Green Sickle" is advocated which, if adopted and implemented, would link National Parks and forest reserves from the savanna down to the Atlantic coast.

    In western Côte d'lvoire. there are two promising areas where conservation efforts could still produce worthwhile results: 1. the hills of Grabo, a hypothetical Pleistocene forest refugium with a high degree of endemism in Côte d'Ivoire, which merits the status of national park; 2. the semi- deciduous forests, which contain many species not found in wetter forests.

    Regional and local gradients result in a great diversity of forests in West Africa. The satellite image on the front cover confirms this broad variation. Forests are not just hectares, trees not just cubic metres. Management of the most species-rich ecosystems on earth is a challenge for present and future generations. It will need international support and the efforts of all those fascinated by this pearl of our blue planet.

    Compte Rendu Séminaire sur l'aménagement intégré des forêts denses humides et des zones agricoles périphériques.
    Vooren, A.P. ; Schork, W. ; Blokhuis, W.A. ; Spijkerman, A.J.C. - \ 1992
    Wageningen : La Fondation Tropenbos (Tropenbos Series 1) - ISBN 9789051130126 - 307
    bosbouw - oerbossen - tropische regenbossen - vegetatie - agroforestry - agrosilviculturele systemen - landgebruik - tropen - bosbedrijfsvoering - planning - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - ivoorkust - oude bossen - forestry - virgin forests - tropical rain forests - vegetation - agroforestry - agrosilvicultural systems - land use - tropics - forest management - planning - pastures - forests - agricultural land - relationships - deforestation - afforestation - cote d'ivoire - old-growth forests
    The Celos management system: a provisional manual.
    Graaf, N.R. de; Bodegom, A.J. van - \ 1991
    Wageningen : IKC/NBLF/LNV en Sticht. Bosbouw Ontwikkelingssamenwerking BOS - 43
    kroondak - kroon - bosbedrijfsvoering - bosbouw - handleidingen - natuurlijke verjonging - planning - suriname - bomen - tropische regenbossen - tropen - vegetatie - oerbossen - werkplannen - oude bossen - canopy - crown - forest management - forestry - guide books - natural regeneration - planning - suriname - trees - tropical rain forests - tropics - vegetation - virgin forests - working plans - old-growth forests
    Diagnosis of Northern Queensland rain forests: the impact of selection silviculture. An independent study, contracted by the Department of Forestry, Queensland, Australia.
    Oldeman, R.A.A. ; Meer, P.J. van der - \ 1988
    Wageningen : LU - 70
    australië - bosbouw - houtteelt - tropische regenbossen - tropen - vegetatie - natuurlijke opstanden - australia - forestry - silviculture - tropical rain forests - tropics - vegetation - natural stands
    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.

    A silvicultural system for natural regeneration of tropical rain forest in Suriname
    Graaf, N.R. de - \ 1986
    Landbouwhogeschool Wageningen. Promotor(en): R.A.A. Oldeman; J.H.A. Boerboom. - Wageningen : Landbouwhogeschool - ISBN 9789090012391 - 250
    kroondak - kroon - bosbouweconomie - bosbedrijfsvoering - bosbouw - bossen - natuurlijke verjonging - suriname - tropische regenbossen - tropen - vegetatie - canopy - crown - forest economics - forest management - forestry - forests - natural regeneration - suriname - tropical rain forests - tropics - vegetation

    A polycyclic system is proposed and discussed for the economically accessible mesophytic (evergreen seasonal) forests in Suriname. In this system, known as Celos Silvicultural System, a restricted amount of about 20 m 3quality timber is taken once about every 20 years in a well controlled selection felling operation. This seemed to be the best compromise between economic demands and ecologic constraints in the highly mixed forest growing on chemically very poor soils. It was found that selection felling had to be followed by refinement using arboricides, three times during the cycle, to release commercial species, and provide economically sufficient increment. The system was tested experimentally over more than a decade. Main principles were maintenance of a high level of biomass to prevent leaching of nutrients from the ecosystem, and minimum interference, assuming the original forest is best adapted to ecological conditions.

    The results of four big field experiments are given in many tables, graphs and stereophotographs.

    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
    Patterns in tree and branch-fall in a West-African rain forest
    Vooren, A.P. van - \ 1985
    Wageningen : LH - 34
    vertakking - dode bomen - dood - ecologie - bosbouw - gebruiksduur - natuurlijke takafstoting - tropische regenbossen - tropen - vegetatie - west-afrika - branching - dead trees - death - ecology - forestry - longevity - natural pruning - tropical rain forests - tropics - vegetation - west africa
    Voortgangsrapport 1978 - 1982 van het project LH/UvS 01 (MAB-project 949) "Antropogene ingrepen in het ecosysteem tropisch regenwoud"
    Schmidt, P. - \ 1983
    Paramaribo : Universiteit van Suriname (CELOS rapporten no. 136) - 24
    schoonmaken - bosbouw - subtropen - suriname - bomen - tropische regenbossen - tropen - vegetatie - oerbossen - oude bossen - bosopstanden - cleaning - forestry - subtropics - suriname - trees - tropical rain forests - tropics - vegetation - virgin forests - old-growth forests - forest stands
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