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.

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Growth and yield of mixed versus pure stands of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) analysed along a productivity gradient through Europe
Pretzsch, H. ; Ammer, C. ; Barbeito, I. ; Mohren, G.M.J. ; Ouden, J. den; Verheyen, K. - \ 2015
European Journal of Forest Research 134 (2015)5. - ISSN 1612-4669 - p. 927 - 947.
spruce picea-abies - long-term experiments - norway spruce - species forests - structural complexity - temperate forests - plant-communities - modeling approach - crown plasticity - tree diversity
Mixing of complementary tree species may increase stand productivity, mitigate the effects of drought and other risks, and pave the way to forest production systems which may be more resource-use efficient and stable in the face of climate change. However, systematic empirical studies on mixing effects are still missing for many commercially important and widespread species combinations. Here we studied the growth of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in mixed versus pure stands on 32 triplets located along a productivity gradient through Europe, reaching from Sweden to Bulgaria and from Spain to the Ukraine. Stand inventory and taking increment cores on the mainly 60–80 year-old trees and 0.02–1.55 ha sized, fully stocked plots provided insight how species mixing modifies the structure, dynamics and productivity compared with neighbouring pure stands. In mixture standing volume (+12 %), stand density (+20 %), basal area growth (+12 %), and stand volume growth (+8 %) were higher than the weighted mean of the neighbouring pure stands. Scots pine and European beech contributed rather equally to the overyielding and overdensity. In mixed stands mean diameter (+20 %) and height (+6 %) of Scots pine was ahead, while both diameter and height growth of European beech were behind (-8 %). The overyielding and overdensity were independent of the site index, the stand growth and yield, and climatic variables despite the wide variation in precipitation (520–1175 mm year-1), mean annual temperature (6–10.5 °C), and the drought index by de Martonne (28–61 mm °C-1) on the sites. Therefore, this species combination is potentially useful for increasing productivity across a wide range of site and climatic conditions. Given the significant overyielding of stand basal area growth but the absence of any relationship with site index and climatic variables, we hypothesize that the overyielding and overdensity results from several different types of interactions (light-, water-, and nutrient-related) that are all important in different circumstances. We discuss the relevance of the results for ecological theory and for the ongoing silvicultural transition from pure to mixed stands and their adaptation to climate change.
Diel growth dynamics in tree stems: linking anatomy and ecophysiology
Steppe, K. ; Sterck, F.J. ; Deslauriers, A. - \ 2015
Trends in Plant Science 20 (2015)6. - ISSN 1360-1385 - p. 335 - 343.
diameter variations - wood formation - sap-flow - water relations - hydraulic safety - phloem transport - munch hypothesis - turgor pressure - plant-responses - norway spruce
Impacts of climate on stem growth in trees are studied in anatomical, ecophysiological, and ecological disciplines, but an integrative framework to assess those impacts remains lacking. In this opinion article, we argue that three research efforts are required to provide that integration. First, we need to identify the missing links in diel patterns in stem diameter and stem growth and relate those patterns to the underlying mechanisms that control water and carbon balance. Second, we should focus on the understudied mechanisms responsible for seasonal impacts on such diel patterns. Third, information on stem anatomy and ecophysiology should be integrated in the same experiments and mechanistic plant growth models to capture both diel and seasonal scales.
European Mixed Forests: Definition and research perspectives
Bravo-Oviedo, A. ; Pretzsch, H. ; Ammer, C. ; Andenmatten, E. ; Barbati, A. ; Barreiro, S. ; Brang, P. ; Bravo, F. ; Coll, L. ; Corona, P. ; Ouden, J. den - \ 2014
Forest Systems 23 (2014)3. - ISSN 2171-5068 - p. 518 - 533.
stand-density index - fagus-sylvatica l. - species stands - norway spruce - picea-abies - pure stands - biomass allocation - climate-change - biodiversity - productivity
Aim of study: We aim at (i) developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii) briefly review the research perspectives in mixed forests. Area of study: The definition is developed in Europe but can be tested worldwide. Material and methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests. Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any developmental stage, sharing common resources (light, water, and/or soil nutrients). The presence of each of the component species is normally quantified as a proportion of the number of stems or of basal area, although volume, biomass or canopy cover as well as proportions by occupied stand area may be used for specific objectives. A variety of structures and patterns of mixtures can occur, and the interactions between the component species and their relative proportions may change over time. The research perspectives identified are (i) species interactions and responses to hazards, (ii) the concept of maximum density in mixed forests, (iii) conversion of monocultures to mixed-species forest and (iv) economic valuation of ecosystem services provided by mixed forests. Research highlights: The definition is considered a high-level one which encompasses previous attempts to define mixed forests. Current fields of research indicate that gradient studies, experimental design approaches, and model simulations are key topics providing new research opportunities.
Wood structural differences between northern and southern beech provenances growing at a moderate site
Eilmann, B. ; Sterck, F.J. ; Wegner, L. ; Vries, S.M.G. de; Arx, G. von; Mohren, G.M.J. ; Ouden, J. den; Sass-Klaassen, U.G.W. - \ 2014
Tree Physiology 34 (2014)8. - ISSN 0829-318X - p. 882 - 893.
fagus-sylvatica l. - climate-change - european beech - scots pine - phenotypic plasticity - forest trees - drought tolerance - quercus-petraea - pubescent oak - norway spruce
Planting provenances originating from southern to northern locations has been discussed as a strategy to speed up species migration and mitigate negative effects of climate change on forest stability and productivity. Especially for drought-susceptible species such as European beech (Fagus sylvatica L.), the introduction of drought-tolerant provenances from the south could be an option. Yet, beech has been found to respond plastically to environmental conditions, suggesting that the climate on the plantation site might be more important for tree growth than the genetic predisposition of potentially drought-adapted provenances. In this study, we compared the radial growth, wood-anatomical traits and leaf phenology of four beech provenances originating from southern (Bulgaria, France) and northern locations (Sweden, the Netherlands) and planted in a provenance trial in the Netherlands. The distribution of precipitation largely differs between the sites of origin. The northern provenances experience a maximum and the southern provenances experience a minimum of rainfall in summer. We compared tree productivity and the anatomy of the water-conducting system for the period from 2000 to 2010, including the drought year 2003. In addition, tree mortality and the timing of leaf unfolding in spring were analysed for the years 2001, 2007 and 2012. Comparison of these traits in the four beech provenances indicates the influence of genetic predisposition and local environmental factors on the performance of these provenances under moderate site conditions. Variation in radial growth was controlled by environment, although the growth level slightly differed due to genetic background. The Bulgarian provenance had an efficient water-conducting system which was moreover unaffected by the drought in 2003, pointing to a high ability of this provenance to cope well with dry conditions. In addition, the Bulgarian provenance showed up as most productive in terms of height and radial growth. Altogether, we conclude that the similarity in ring-width variation among provenances points to environmental control of this trait, whereas the differences encountered in wood-anatomical traits between the well-performing Bulgarian provenance and the other three provenances, as well as the consistent differences in flushing pattern over 3 years under various environmental conditions, support the hypothesis of genetic control of these features.
Suitability of close-to-nature silviculture for adapting temperate European forests to climate change
Brang, P. ; Spathelf, P. ; Larsen, J.B. ; Bauhus, J. ; Boncina, A. ; Mohren, G.M.J. - \ 2014
Forestry 87 (2014). - ISSN 0015-752X - p. 492 - 503.
spruce picea-abies - fagus-sylvatica l. - norway spruce - ecological stability - species-diversity - stand structure - change impacts - mixed stands - management - drought
In many parts of Europe, close-to-nature silviculture (CNS) has been widely advocated as being the best approach for managing forests to cope with future climate change. In this review, we identify and evaluate six principles for enhancing the adaptive capacity of European temperate forests in a changing climate: (1) increase tree species richness, (2) increase structural diversity, (3) maintain and increase genetic variation within tree species, (4) increase resistance of individual trees to biotic and abiotic stress, (5) replace high-risk stands and (6) keep average growing stocks low. We use these principles to examine how three CNS systems (single-tree selection, group selection and shelterwood) serve adaptation strategies. Many attributes of CNS can increase the adaptive capacity of European temperate forests to a changing climate. CNS promotes structural diversity and tree resistance to stressors, and growing stocks can be kept at low levels. However, some deficiencies exist in relation to the adaptation principles of increasing tree species richness, maintaining and increasing genetic variation, and replacing high-risk stands. To address these shortcomings, CNS should make increased use of a range of regeneration methods, in order to promote light-demanding tree species, non-native species and non-local provenances.
What causes the differences between national estimates of carbon emissions from forest management and large-scale models?
Groen, T.A. ; Verkerk, P.J. ; Böttcher, H. ; Grassi, G. ; Cienciala, E. ; Black, K.G. ; Fortin, M.J. ; Koethke, M. ; Lethonen, A. ; Nabuurs, G.J. ; Petrova, L. ; Blujdea, V. - \ 2013
Environmental Science & Policy 33 (2013). - ISSN 1462-9011 - p. 222 - 232.
biomass equations - norway spruce - scots pine - finland - birch
Under the United Nations Framework Convention for Climate Change all Parties have to report on carbon emissions and removals from the forestry sector. Each Party can use its own approach and country specific data for this. Independently, large-scale models exist (e.g. EFISCEN and G4M as used in this study) that assess emissions and removals from this sector by applying a unified approach to each country, still often based on country specific data. Differences exist between the national reported values and the calculations from the large scale models. This study compares these models with national reporting efforts for 24 EU countries for the period 2000–2008, and identifies the most likely causes for differences. There are no directly identifiable single input parameters that could be targeted to fully close the gap between country and model estimates. We found that the method applied by the country (i.e. stock-difference or gain-loss) contributes significantly to differences for EFISCEN and was the best explaining variable for G4M, although for the latter it was not significant. Other variables (biomass expansion factors, harvest volumes and the way harvest losses are treated) were not found to provide a conclusive explanation for the differences between the model estimations and the country submissions in an over-al analysis. However, at the level of individual countries several different causes for differences were identified. This suggests that to really close the gap between country submissions and large scale models, close collaboration between modellers and country experts is needed, calling for openness and willingness to share relevant data and to compare GHG inventories with independent estimates. This would enable to improve the confidence both in historical GHG inventories and in the models which are needed to project the future forest sink for several policy issues.
Resin secretory structures of Boswellia papyrifera and implications for frankincense yield
Tolera, M. ; Menger, D. ; Sass, U.G.W. ; Sterck, F.J. ; Copini, P. ; Bongers, F. - \ 2013
Annals of Botany 111 (2013)1. - ISSN 0305-7364 - p. 61 - 68.
timber forest product - northern ethiopia - norway spruce - metema district - bark anatomy - tree size - conifers - biosynthesis - canals - plants
Frankincense, a gum-resin, has been tapped from Boswellia papyrifera trees for centuries. Despite the intensive tapping and economic interest of B. papyrifera, information on the resin secretory structures, which are responsible for synthesis, storage and transport of frankincense, is virtually absent. This study describes the type, architecture and distribution of resin secretory structures of B. papyrifera and its relevance for the ecophysiology and economic use of the tree. The type and architecture of resin secretory structures present in bark and wood was investigated from transversal, tangential and radial sections of bark and wood samples. The diameter and density (number of resin canals mm(2)) of axial resin canals were determined from digital images of thin sections across the different zones of inner bark. Resin canals form a three-dimensional network within the inner bark. Yet, the intact resin-conducting and producing network is on average limited to the inner 66 mm of the inner bark. Within the inner bark, the density of non-lignified axial resin canals decreases and the density of lignified resin canals increases from the vascular cambium towards the outer bark. In the wood, only radial resin canals were encountered. Frankincense tapping techniques can be improved based on knowledge of bark anatomy and distribution and architecture of resin secretory structures. The suggested new techniques will contribute to a more sustainable frankincense production that enhances the contribution of frankincense to rural livelihoods and the national economy.
Crown plasticity and neighborhood interactions of European beech (Fagus sylvatica L.) in an old-growth forest
Schröter, M. ; Härdtle, W. ; Oheimb, G. von - \ 2012
European Journal of Forest Research 131 (2012)3. - ISSN 1612-4669 - p. 787 - 798.
tree canopy displacement - norway spruce - stand level - dead wood - mixed stands - picea-abies - asymmetry - dynamics - competition - patterns
Competition for canopy space is a process of major importance in forest dynamics. Although virgin and old-growth European beech (Fagus sylvatica L.) forests in Europe have been studied for many years, there are to date no studies of individual-tree crown plasticity and the way this is influenced by local neighborhood interactions in these forests. In this study, we analyzed crown plasticity and local neighborhood interactions of individual trees in the upper canopy of the old-growth beech forests of Serrahn, northeast Germany. In a 2.8-ha sample plot, we measured crown radii of all upper canopy trees and analyzed the direction and extent of crown asymmetry. Size, relative position, and distance of neighboring trees were used to construct vectors of neighborhood asymmetry within different distances from target trees. The crowns of beech trees showed strong morphological plasticity. Mean absolute and relative displacement of crown centers from the stem base were 1.95 m and 0.37, respectively. Circular–circular rank correlation coefficients between the direction of crown displacement and the direction of neighborhood pressure showed that trees strongly positioned their crowns away from local neighbors. Highest correlation coefficients were obtained when basal area and relative position of neighboring trees within a radial distance of 12 m were considered. Clark and Evans index and Ripley’s K-function showed that crowns were more regularly distributed than stems. Projected canopy cover was about 10% higher than canopy cover with simulated circular crowns. We conclude that the crowns of older beech trees have a high ability to plastically respond to changes in the local canopy conditions, enabling very effective exploitation of canopy space.
The influence of storm-induced microsites to tree regeneration patterns in boreal and hemiboreal forest
Vodde, F. ; Jogiste, K. ; Kubota, Y. ; Kuuluvainen, T. ; Koster, K. ; Lukjanova, A. ; Metslaid, M. ; Yoshida, T. - \ 2011
Journal of Forest Research 16 (2011)3. - ISSN 1341-6979 - p. 155 - 167.
picea-abies forest - old-growth forest - experimental hurricane blowdown - intermediate wind disturbance - northern temperate forests - pinus-sylvestris forest - coarse woody debris - norway spruce - catastrophic windthrow - natural regeneration
We reviewed studies dealing with regeneration under variable conditions in boreal and hemiboreal forests as affected by different microsite types by tree species functional groups. Generally, the importance of storm-induced microsites for regeneration dynamics in boreal forests depends on several factors: (1) distribution and type of microsites (generated by storm characteristics and stand conditions); (2) viable seed supply (stand history, species dispersal traits and status of surviving trees) and their species' life history strategy; (3) climatic and site conditions (pre-storm conditions and storm-induced changes); and (4) delayed storm effects, such as retarded falling of trees, favoured vegetation growth, etc. Studies acknowledging the significance of microsites were mostly related to intermediate or severe events, causing sufficient changes in resource levels and growth conditions, and influencing extrinsic factors such as frost heaving, erosion and browsing. Also, the dispersal traits of available tree species, including sprouting and response of surviving trees, such as canopy expansion, should be considered in evaluating microsite importance in individual cases. In intermediate to severe windstorm events, pioneer species are generally profiting most from the additional offer in microsites, requiring bare mineral soil and elevated locations for their establishment and growth. Under gap dynamics, shade-tolerant species benefit from dead wood and elevated locations as these offer safe sites in stands with abundant understorey vegetation.
Inter-specific competition in mixed forests of Douglas-fir (Pseudotsuga menziesii) and common beech (Fagus sylvatica) under climate change – a model-based analysis
Reyer, C. ; Lasch, P. ; Mohren, G.M.J. ; Sterck, F.J. - \ 2010
Annals of Forest Science 67 (2010)8. - ISSN 1286-4560 - p. 805 - 805.
interspecific competition - european beech - volume growth - norway spruce - root biomass - stands - management - l. - netherlands - simulation
Mixed forests feature competitive interactions of the contributing species which influence their response to environmental change. • We analyzed climate change effects on the inter-specific competition in a managed Douglas-fir/beech mixed forest. • Therefore, we initialised the process-based forest model 4C with published fine root biomass distributions of Douglas-fir/beech stands and a stand composition originating from yield tables to simulate forest growth under regional climate change scenarios for a Dutch and a German site. • The number of days when the tree water demand exceeded the soil water supply was higher for Douglas-fir than for beech. After 45 simulation years the proportion of basal area covered by beech increased from one to seven percent. Beech’s competitive strength is mainly explained by the fine root biomass distributions and is highest under the historic climate and the driest climate change scenarios. Higher net primary production (NPP) under warmer/wetter climate but decreased NPP under warmer/drier conditions confirms Douglas-fir’s high sensitivity to limited water supply. • Simulated climate change does not substantially alter the interaction of the two species but the drought-stressed trees are more susceptible to insects or pathogens. The concept of complementary water use highlights the importance of mixed forest for climate change adaptation.
EU-wide maps of growing stock and above-ground biomass in forests based on remote sensing and field measurements
Gallaun, H. ; Zanchi, G. ; Nabuurs, G.J. ; Hengeveld, G.M. ; Schardt, M. ; Verkerk, P.J. - \ 2010
Forest Ecology and Management 260 (2010)3. - ISSN 0378-1127 - p. 252 - 261.
maximum-likelihood classification - expansion factors - inventory data - norway spruce - shoot ratios - area - membership - root
The overall objective of this study was to combine national forest inventory data and remotely sensed data to produce pan-European maps on growing stock and above-ground woody biomass for the two species groups " broadleaves" and " conifers" An automatic up-scaling approach making use of satellite remote sensing data and field measurement data was applied for EU-wide mapping of growing stock and above-ground biomass in forests. The approach is based on sampling and allows the direct combination of data with different measurement units such as forest inventory plot data and satellite remote sensing data. For the classification, data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used. Comprehensive field measurement data from national forest inventories for 98,979 locations from 16 countries were used for which tree species and growing stock estimates were available. The classification results were evaluated by comparison with regional estimates derived independently from the classification from national forest inventories. The validation at the regional level shows a high correlation between the classification results and the field based estimates with correlation coefficient r=0.96 for coniferous, r=0.94 for broadleaved and r=0.97 for total growing stock per hectare. The mean absolute error of the estimations is 25m3/ha for coniferous, 20m3/ha for broadleaved and 25m3/ha for total growing stock per hectare. Biomass conversion and expansion factors were applied to convert the growing stock classification results to carbon stock in above-ground biomass. As results of the classification, coniferous and broadleaved growing stock as well as carbon stock of the above-ground biomass is mapped on a wall-to-wall basis with a spatial resolution of 500m×500m per grid cell. The mapped area is 5millionkm2, of which 2millionkm2 are forests, and covers the whole European Union, the EFTA countries, the Balkans, Belarus, the Ukraine, Moldova, Armenia, Azerbaijan, Georgia and Turkey
Carbon storage and sequestration potential of selected tree species in India
Kaul, M. ; Mohren, G.M.J. ; Dadhwal, V.K. - \ 2010
Mitigation and Adaptation Strategies for Global Change 15 (2010)5. - ISSN 1381-2386 - p. 489 - 510.
dry-matter dynamics - poplar plantations - forest management - climate-change - scots pine - biomass production - central himalaya - tectona-grandis - norway spruce - wood products
A dynamic growth model (CO2FIX) was used for estimating the carbon sequestration potential of sal (Shorea Robusta Gaertn. f.), Eucalyptus (Eucalyptus Tereticornis Sm.), poplar (Populus Deltoides Marsh), and teak (Tectona Grandis Linn. f.) forests in India. The results indicate that long-term total carbon storage ranges from 101 to 156 Mg C¿ha-1, with the largest carbon stock in the living biomass of long rotation sal forests (82 Mg C¿ha-1). The net annual carbon sequestration rates were achieved for fast growing short rotation poplar (8 Mg C¿ha-1¿yr-1) and Eucalyptus (6 Mg C¿ha-1¿yr-1) plantations followed by moderate growing teak forests (2 Mg C¿ha-1¿yr-1) and slow growing long rotation sal forests (1 Mg C¿ha-1¿yr-1). Due to fast growth rate and adaptability to a range of environments, short rotation plantations, in addition to carbon storage rapidly produce biomass for energy and contribute to reduced greenhouse gas emissions. We also used the model to evaluate the effect of changing rotation length and thinning regime on carbon stocks of forest ecosystem (trees¿+¿soil) and wood products, respectively for sal and teak forests. The carbon stock in soil and products was less sensitive than carbon stock of trees to the change in rotation length. Extending rotation length from the recommended 120 to 150 years increased the average carbon stock of forest ecosystem (trees¿+¿soil) by 12%. The net primary productivity was highest (3.7 Mg ha-1¿yr-1) when a 60-year rotation length was applied but decreased with increasing rotation length (e.g., 1.7 Mg ha-1¿yr-1) at 150 years. Goal of maximum carbon storage and production of more valuable saw logs can be achieved from longer rotation lengths. ‘No thinning’ has the largest biomass, but from an economical perspective, there will be no wood available from thinning operations to replace fossil fuel for bioenergy and to the pulp industry and such patches have high risks of forest fires, insects etc. Extended rotation lengths and reduced thinning intensity could enhance the long-term capacity of forest ecosystems to sequester carbon. While accounting for effects of climate change, a combination of bioenergy and carbon sequestration will be best to mitigation of CO2 emission in the long term
Hydrolytic stability of water-soluble spruce O-acetyl galactoglucomannans
Xu, C. ; Pranovich, A. ; Hemmimg, J. ; Holmbom, B. ; Albrecht, S.A. ; Schols, H.A. ; Willfor, S. - \ 2009
Holzforschung 63 (2009)1. - ISSN 0018-3830 - p. 61 - 68.
molecular-weight changes - norway spruce - thermomechanical pulp - acid-hydrolysis - picea-abies - degradation - kinetics - chitosan - polymer
Water-soluble native O-acetyl galactoglucomannan (GGM) from spruce is a polysaccharide that can be produced in an industrial scale. To develop GGM applications, information is needed on its stability, particularly under acidic conditions. Therefore, acid hydrolysis of spruce GGM was investigated at various pH levels and temperatures. The results allow an estimation of the stability of GGM under food processing conditions and in biological systems. Determination of the average molar mass demonstrated that spruce GGM was stable at pH 1 and 37°C, as well as at pH 3 and 70°C. GGM was hydrolysed at pH 1 and 90°C. GGM oligomers and monomers were detected after degradation. Some of the oligomers contained O-acetyl groups. Monosaccharides were the predominant products in the hydrolysates after treatment at pH 1 and 90°C for 48 h. Pentoses, present in GGM samples as impurities, were released more easily than GGM hexoses. Glucose was more difficult to release than mannose. Traces of 6-deoxy-mannose and levoglucosan were found in the hydrolysates, indicating further degradation of hydrolysed monosaccharides.
Extractable and dissolved soil organic nitrogen - A quantitative assessment
Ros, G.H. ; Hoffland, E. ; Kessel, C. van; Temminghoff, E.J.M. - \ 2009
Soil Biology and Biochemistry 41 (2009)6. - ISSN 0038-0717 - p. 1029 - 1039.
common arable topsoils - 0.01 m cacl2 - microbial biomass - n-mineralization - norway spruce - agricultural soils - forest soils - sandy soils - seasonal-changes - pastoral soils
Extractable Organic N (EON) or Dissolved Organic Nitrogen (DON) pools are often analyzed to predict N mineralisation, N leaching, and to evaluate agricultural (nutrient) management practices. Size and characteristics of both pools, however, are strongly influenced by methodology. Quantifying the influence of methodology can increase the accuracy of soil tests to predict N mineralisation, improve model simulations, and can help to quantify the contribution of the EON and DON pools to soil N cycling. We estimated the relative impact of methodological, management, and environmental factors on EON and DON, using a meta-analysis approach based on 127 studies. Our results indicate that the EON and DON pools are neither similar in size nor controlled by the same factors. The influence of factors controlling EON generally decreased in the order of methodology (¿10¿2400%), followed by environment (¿11¿270%) and management (¿16¿77%). DON concentrations were primarily controlled by management factors: different land use and fertilisation caused a variation of 37¿118%. Seasonal variations in DON concentrations were generally smaller than variations in EON, suggesting that high mineralisation and sorption rates buffer DON. The large range in EON as affected by different methodology emphasizes the importance of using appropriate and standardized methods for the determination of EON. The determination of DON can be useful to estimate leaching losses. EON, however, can be used to assess the impact of soil management practices on the turnover rate of labile soil organic matter pools
Development of forest carbon budget and wood production in the Czech Republic until 2060
Cienciala, E. ; Exnerová, Z. ; Schelhaas, M.J. - \ 2008
Annals of Forest Science 65 (2008). - ISSN 1286-4560 - p. 603 - 612.
biomass functions - uncertainty estimation - european forests - scenario model - norway spruce - scots pine - soil - switzerland - dynamics - litter
This study describes the scenarios of likely development of carbon pools in managed forest ecosystems of the Czech Republic. The analysis was based on a matrix scenario model (EFISCEN), adopting a novel parameterization based on forest stand site types and forest typology. The model was constrained by practical management rules as prescribed by the Czech Forestry Act and used to assess production potential for the next five decades under three management and three climate scenarios. The analysis provided data on carbon pool development, including both tree biomass and soil compartments. $\\bullet$ For the tested scenarios of sustainable forest management (wood removals not exceeding increment) the model indicated a slight increase of soil carbon pool. For the possibly largest removals (maximum sustainable felling scenario), soil carbon stabilized within two or three decades reaching a mean value of about 8.1 kg/m2 for. At the same time, the mean carbon stock held in biomass reached about 10.2 kg/m2 including belowground parts. No decline of soil carbon was observed for any of the tested scenarios. $\\bullet$ We conclude that it is reasonable to assume that soil carbon is not a source of carbon under the current management constraints as implemented in the Czech forestry practice.
Ectomycorrhizal fungal diversity: seperating the wheat from the chaff
Rinaldi, A.C. ; Comandini, O. ; Kuyper, T.W. - \ 2008
Fungal Diversity 33 (2008). - ISSN 1560-2745 - p. 1 - 45.
truffle-like fungi - n-15 isotopic fractionation - ribosomal dna-sequences - pure culture synthesis - mixed-conifer forest - picea-abies - norway spruce - molecular phylogeny - douglas-fir - new-zealand
Thousands of ectomycorrhizal (ECM) fungal species exist, but estimates of global species richness of ECM fungi differ widely. Many genera have been proposed as being ECM, but ill a number of studies evidence for the hypothesized ECM habit is lacking. Progress in estimating ECM species richness is therefore slow. Ill this paper we have retrieved studies providing evidence for the ECM habit of fungal species and For the identification of the mycobiont(s) ill specific ECM associations, using published and web-based mycorrhiza literature. The identification methods considered are morpho-anatomical, characterization or naturally occurring ECMs, pure Culture synthesis, molecular identification, and isotopic evidence. In addition, phylogenetic information is also considered as a relevant criterion to assess ECM habit. OF 343 fungal genera for which all ECM status has been alleged, about two thirds have Supportive published evidence or ECM Status can be at least hypothesized. For the remaining taxa, Currently no indication exists as for their I-CM nutritional habit, besides field observations or associations with putative hosts. Our survey clearly indicates that current knowledge of ECM fungal diversity, as Supported by experimental evidence, is only partly complete, and that inclusion of many Funga genera in this trophic and ecological category is not verified at this stage. Care must thus be used when compiling lists of ECM and saprotrophic full studies oil the basis of published information only. On the basis of our literature search we conservatively estimate ECM species richness around 7750 species. However, oil the basis of estimates of knowns and unknowns in macromycete diversity, a final estimate or ECM species richness Would likely be between 20000 and 25000.
Hotspots of the European forests carbon cycle
Nabuurs, G.J. ; Thürig, E. ; Heidema, N. ; Armolaitis, K. ; Biber, P. ; Cieciala, E. ; Kaufmann, E. ; Mäkipää, R. ; Nilsen, P. ; Petritsch, R. ; Pristova, T. ; Rock, J. ; Schelhaas, M.J. ; Sievanen, R. ; Somogyi, Z. ; Vallet, P. - \ 2008
Forest Ecology and Management 256 (2008)3. - ISSN 0378-1127 - p. 194 - 200.
bosecologie - koolstofcyclus - broeikasgassen - milieubeleid - europa - forest ecology - carbon cycle - greenhouse gases - environmental policy - europe - norway spruce - whole-tree - compensatory fertilization - rotation length - managed forests - climate-change - meta analysis - picea-abies - storage - stands
This paper is the outcome of a group discussion held at the Savonlinna meeting `Management of forest ecosystems and its impact on the GHG budget¿. The aim of this break-out group discussion was to `Characterize forest management impacts on the GHG budget of forest ecosystems in different European regions¿. In this paper we briefly characterize different options that a forest owner has in order to maintain or maximize forest carbon pools and carbon sequestration. These hectare scale descriptions of measures are then regarded in connection to the current state of European forests and how they can be combined with ongoing management trends and local issues. We point out the various possibilities that exist in European forests, where they are located, and where they could possibly be combined with adaptation. We identify these hotspots for largest growing stocks, largest peat areas, and, e.g. largest risks for loss of carbon due to fire or urban sprawl. We conclude that one common strategy cannot be designed. Within each region, local solutions have to be found that optimize goals and aim at integrated and sustainable land use
Fine roots and ectomycorrhizas as indicators of environmental change.
Cudlin, P. ; Kieliszewska-Rokicka, B. ; Rudawska, M. ; Grebenc, T. ; Alberton, O. ; Lehto, T. ; Bakker, M.R. ; Borja, I. ; Konopka, B. ; Leski, T. ; Kraigher, H. ; Kuyper, T.W. - \ 2007
Plant Biosystems 141 (2007)3. - ISSN 1126-3504 - p. 406 - 425.
spruce picea-abies - pine pinus-sylvestris - experimental nitrogen addition - atmospheric carbon-dioxide - air ozone fumigation - sitchensis bong carr - norway spruce - scots pine - fagus-sylvatica - fungal communities
Human-induced and natural stress factors can affect fine roots and ectomycorrhizas. Therefore they have potential utility as indicators of environmental change. We evaluated, through meta-analysis, the magnitude of the effects of acidic deposition, nitrogen deposition, increased ozone levels, elevated atmospheric carbon dioxide, and drought on fine roots and ectomycorrhizal (ECM) characteristics. Ectomycorrhizal colonization was an unsuitable parameter for environmental change, but fine root length and biomass could be useful. Acidic deposition had a significantly negative impact on fine roots, root length being more sensitive than root biomass. There were no significant effects of nitrogen deposition or elevated tropospheric ozone on the quantitative root parameters. Elevated CO2 had a significant positive effect. Drought had a significantly negative effect on fine root biomass. The negative effect of acidic deposition and the positive effect of elevated CO2 increased over time, indicating that effects were persistent contrary the other factors. The meta-analysis also showed that experimental conditions, including both laboratory and field experiments, were a major source of variation. In addition to quantitative changes, environmental changes affect the species composition of the ectomycorrhizal fungal community.
Introducing tree interactions in wind damage simulations
Schelhaas, M.J. ; Kramer, K. ; Peltola, H. ; Werf, D.C. van der; Wijdeven, S.M.J. - \ 2007
Ecological Modelling 207 (2007)2-4. - ISSN 0304-3800 - p. 197 - 209.
pinus-pinaster ait. - forest stands - scots pine - mechanical stability - tunnel measurements - drag relationships - field-measurements - individual-tree - norway spruce - models
Wind throw is an important risk factor in forest management in North-western Europe. In recent years, mechanistic models have been developed to estimate critical wind speeds needed to break or uproot the average tree of a forest stand. Based on these models, we developed a wind damage module for the individual tree model ForGEM (Forest Genetics, Ecology and Management). For a given wind speed this module assesses the forces on each individual tree, based on the tree dimensions, and support and sheltering provided by other trees. Due to this individual approach, irregular stands can also be assessed. The module is demonstrated on Douglas fir stands (Pseudotsuga menziesii (Mirb.) Franco) of different densities in the Netherlands. Patterns of damage are explained, both in freshly exposed stands as well as in sheltered stands. Wind speeds needed to cause damage approximated those of known wind throw events. The wind damage module proved to be very sensitive to simulated tree heights and diameters. Furthermore, the newly introduced support mechanism played an important role in the stability of trees and stands. Lower individual tree stability in dense stands was clearly compensated for by the support of other trees.
Specific root length as an indicator of environmental change
Ostonen, I. ; Püttsepp, Ü. ; Biel, C. ; Alberton, O. ; Bakker, M.R. ; Löhmus, K. ; Majdi, H. ; Metcalfe, J.D. ; Olsthoorn, A.F.M. ; Pronk, A.A. ; Vanguelova, E. ; Weih, M. ; Brunner, I. - \ 2007
Plant Biosystems 141 (2007)3. - ISSN 1126-3504 - p. 426 - 442.
spruce picea-abies - elevated atmospheric co2 - pine pinus-sylvestris - soil solution chemistry - potential growth-rate - fine-root - norway spruce - l. karst. - nutrient availability - silver birch
Specific root length (SRL, m g-1) is probably the most frequently measured morphological parameter of fine roots. It is believed to characterize economic aspects of the root system and to be indicative of environmental changes. The main objectives of this paper were to review and summarize the published SRL data for different tree species throughout Europe and to assess SRL under varying environmental conditions. Meta-analysis was used to summarize the response of SRL to the following manipulated environmental conditions: fertilization, irrigation, elevated temperature, elevated CO2, Al-stress, reduced light, heavy metal stress and physical disturbance of soil. SRL was found to be strongly dependent on the fine root classes, i.e. on the ectomycorrhizal short roots (ECM), and on the roots
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