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  • AGRIS (United Nations, Food and Agriculture Organization)  (43)
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  • 1
    Language: English
    In: Plant and Soil, 2010, Vol.333(1), pp.93-103
    Description: Assessment of belowground interactions in mixed forests has been largely constrained by the ability to distinguish fine roots of different species. Here, we explored near infrared reflectance spectroscopy (NIRS) to predict the proportion of woody fine roots in mixed samples and analyzed whether the prediction quality of NIRS models is related to the complexity of the fine-root mixture. For model calibration and validation purposes, 11 series of artificial mixed species samples containing known amounts of fine roots of up to four temperate tree species and non-woody plants were prepared. Three types of models with different calibration/validation approaches were developed and tested against external independent data for additional validation. With these models the proportion of each species in root mixtures was predicted accurately with low standard error of prediction (RMSECV/RMSEP 〈6.5%) and high coefficient of determination (r 2  〉 0.93) for all fine-root mixtures. In addition, NIRS models also provided satisfactory estimates for samples with low (〈15%) or no content of particular components. The predictive power of the NIRS models did not decrease substantially with increasing complexity of the root samples. The approach presented here is a promising alternative to hand sorting of fine roots, which may be influenced substantially by operator variation, and it will facilitate investigating belowground interactions between woody species.
    Keywords: Fine roots ; Belowground diversity ; Near-infrared reflectance spectroscopy (NIRS) ; NIRS model ; Species proportions
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 2
    Language: English
    In: Soil biology & biochemistry, 2010, Vol.42, pp.1347-1354
    Description: How the mixture of tree species modifies short-term decomposition has been well documented using litterbag studies. However, how litter of different tree species interact in the long-term is obscured by our inability to visually recognize the species identity of residual decomposition products in the two most decomposed layers of the forest floor (i.e. the Oe and Oa layers respectively). To overcome this problem, we used Near Infrared Reflectance Spectroscopy (NIRS) to determine indirectly the species composition of forest floor layers. For this purpose, controlled mixtures of increasing complexity comprising beech and spruce foliage materials at various stages of decomposition from sites differing in soil acid–base status were created. In addition to the controlled mixtures, natural mixtures of litterfall from mixed stands were used to develop prediction models. Following a calibration/validation procedure, the best regression models to predict the actual species proportion from spectral properties were selected for each tree species based on the highest coefficient of determination (R2) and the lowest root mean square error of prediction (RMSEP). For the validation, the R2 (predictions versus true proportions) were 0.95 and 0.94 for both beech and spruce components in mixtures of materials at all stages of decomposition from the gradient of sites. The R2 decreased only marginally by 0.04 when models were tested on independent samples of similar composition. The best models were used to predict the beech-spruce proportion in Oe and Oa layers of unknown composition. They provided in most cases plausible predictions when compared to the composition of the canopy above the sampling points. Thus, tedious and potentially erroneous hand sorting of forest floor layers may be replaced by the use of NIRS models to determine species composition, even at late stages of decomposition. ; Includes references ; p. 1347-1354.
    Keywords: Forest Soils ; Biodegradation ; Soil Ph ; Prediction ; Calibration ; Forest Trees ; Botanical Composition ; Leaves ; Simulation Models ; Forest Litter ; Soil Horizons ; Organic Horizons ; Overstory ; Near-Infrared Reflectance Spectroscopy ; Model Validation ; Picea Abies ; Temperate Forests ; Accuracy ; Regression Analysis
    ISSN: 0038-0717
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
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  • 3
    Language: English
    In: Biodiversity and Conservation, 2014, Vol.23(14), pp.3519-3542
    Description: A major goal of the Convention on Biological Diversity (CBD) is to improve the protection of biodiversity. One approach to meet this goal is the implementation of strictly protected forest reserves (SPFRs). Many countries have adopted this approach and set target values for SPFRs, for example Germany aims to set aside 5 % of the forest area by 2020 (BMU, Strategie zur Biologischen Vielfalt, 2007). The contribution of SPFRs to biodiversity conservation cannot be assessed without considering the quality or conservation value of these areas. One challenge lies in the selection of specific criteria to evaluate this contribution of existing SPFRs. For Central Europe we reviewed these specific evaluation criteria and their ecological theory and evidence underpinning their relevance for an assessment as well as the interrelations between criteria. In addition, we present a framework for the integration of these criteria into an evaluation process. To identify criteria typically used or recommended for the evaluation of SPFRs, we analyzed the international conventions and reviewed the scientific literature on biodiversity conservation, specifically on area selection, status assessment and gap analysis. Since nearly all criteria were interrelated and operate at different scales, we developed a coherent evaluation framework to integrate them. Within this framework the criteria cover the fundamental aspects: space (completeness and connectivity), time (habitat continuity and persistence), and function (naturalness, rarity/threat and representativeness). This approach, once it is complemented by indicators, may be used to evaluate the extent to which individual SPFRs as well as a system of SPFRs contribute to the protection of natural forest biodiversity at a national level. It may be particularly relevant for Central European countries with a similar ecological, historical and political context.
    Keywords: Forest biodiversity conservation ; Natural forest development ; Protected areas ; Forest conservation ; Evaluation framework ; CBD
    ISSN: 0960-3115
    E-ISSN: 1572-9710
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  • 4
    In: Journal of Animal Ecology, January 2016, Vol.85(1), pp.213-226
    Description: Arthropod communities in water‐filled tree holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. We hypothesized that increasing forest management intensity (ForMI) negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree hole size, detritus amount and changed water chemistry at the tree holes scale. We mapped 910 water‐filled tree holes in two regions in Germany and studied 199 tree hole inhabiting arthropod communities. We found that increasing ForMI indeed significantly reduced arthropod abundance and richness in water‐filled tree holes. The most important indirect effects of management intensity on tree hole community structure were the reduced amounts of detritus for the tree hole inhabiting organisms and changed water chemistry at the tree hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree holes. However, regional species richness in tree holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management‐driven increase in plant diversity at the forest stand scale affected communities of individual tree holes, for example via resource availability for adults. Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water‐filled tree holes. This paper focuses on the mechanisms underlying the negative effects of forest management intensity on diversity and functional composition of arthropods. This not only improves our understanding of community assembly, but also helps to improve conservation strategies aiming at reducing ongoing species loss.
    Keywords: Aquatic Larvae ; Biodiversity Exploratories ; Community Composition ; Dispersal ; Diversity ; Habitat Filter ; Land‐Use Intensity ; Metacommunity ; Phytotelmata ; Species Sorting
    ISSN: 0021-8790
    E-ISSN: 1365-2656
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  • 5
    Language: English
    In: Scandinavian Journal of Forest Research, 01 June 2013, Vol.28(4), pp.346-357
    Description: Coarse woody debris (CWD) is critical for forest ecosystem carbon (C) storage in many ecosystems. Since the turnover of CWD is mostly driven by mineralization, changes in temperature and precipitation may influence its pools and functions. Therefore, we analysed, under controlled conditions,...
    Keywords: Coarse Woody Debris ; Carbon ; Respiration ; Decomposition ; Forestry
    ISSN: 0282-7581
    E-ISSN: 1651-1891
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  • 6
    Language: English
    In: BioScience July 2012, Vol.62(7), pp.633-645
    Description: The majority of the world’s forests are used for multiple purposes, which often include the potentially conflicting goals of timber production and biodiversity conservation. A scientifically validated management approach that can reduce such conflicts is retention forestry, an approach modeled on natural processes, which emerged in the last 25 years as an alternative to clearcutting. A portion of the original stand is left unlogged to maintain the continuity of structural and compositional diversity. We detail retention forestry’s ecological role, review its current practices, and summarize the large research base on the subject. Retention forestry is applicable to all forest biomes, complements conservation in reserves, and represents bottom-up conservation through forest manager involvement. A research challenge is to identify thresholds for retention amounts to achieve desired outcomes. We define key issues for future development and link retention forestry with land-zoning allocation at various scales, expanding its uses to forest restoration and the management of uneven-age forests.
    Keywords: Biology;
    ISSN: 00063568
    E-ISSN: 15253244
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  • 7
    Language: English
    In: Trees, 2013, Vol.27(6), pp.1609-1619
    Description: Sorbus torminalis L. (Crantz) is a rare species in Central European forests with very limited quantitative information on its regeneration and growth dynamics. Since coppicing is no longer practiced in the most parts of Central Europe, it is unclear whether S. torminalis , which has usually a shorter end height than companion species, can persist in high forest systems. Here, we quantified species frequency on three 1 ha sample plots of former oak coppice forest. To determine whether S. torminalis regenerated continuously and how it might compete with oaks, the age of 80 trees was determined, and diameter and height growth were reconstructed for the 20 largest trees by stem analysis. To assess its shade tolerance, photosynthesis was measured for leaves located in high and low light conditions. Dendrochronological data demonstrated that, over the last 80 years, continuous recruitment of S. torminalis occurred. Growth patterns and photosynthesis measurements suggest that S. torminalis is a highly shade-tolerant species. We conclude that abandonment of coppicing in these forests does not threaten the status of S. torminalis , which can persist beneath the canopy of oaks.
    Keywords: Coppice ; Age structure ; Growth ; Light ecology ; Sorbus torminalis ; Wild Service Tree
    ISSN: 0931-1890
    E-ISSN: 1432-2285
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  • 8
    Language: English
    In: Annals of Forest Science, 2013, Vol.70(2), pp.195-207
    Description: CONTEXT : Since storm damage has a large impact on forest management in Central Europe, we investigated the main storm risk factors for two important conifer species, Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) and Norway spruce (Picea abies [L.] Karst.). AIMS : We compared general storm damage levels of Douglas-fir and Norway spruce, the latter being known to have high storm risk among European tree species. METHODS : Generalized linear mixed models and boosted regression trees were applied to recorded storm damage of individual trees from long-term experimental plots in southwest Germany. This included two major winter storm events in 1990 and 1999. Over 40 candidate predictors were tested for their explanatory power for storm damage and summarized into predictor categories for further interpretation. RESULTS : The two most important categories associated with storm damage were timber removals and topographic or site information, explaining between 18 and 54 % of storm damage risk, respectively. Remarkably, general damage levels were not different between Douglas-fir and Norway spruce. CONCLUSION : Under current forest management approaches, Douglas-fir may be considered a species with high storm risk in Central Europe, comparable to that of Norway spruce. ; p. 195-207.
    Keywords: Storm damage ; Risk ; Windthrow ; Douglas-fir ; Norway spruce ; Southwest Germany ; Empirical modeling
    ISSN: 1286-4560
    E-ISSN: 1297-966X
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  • 9
    Language: English
    In: Forests, 2013, Vol.(1), pp.85-103
    Description: Recent studies have shown that, owing to a lack of seed trees, the natural rate of recovery of fire-disturbed bog forests previously dominated by the endemic and endangered conifer Pilgerodendron uviferum (D. Don) Florin is extremely slow. Hence, increasing the number of seed trees in the landscape through restoration planting could remove the principal biotic filter, limiting recovery of these forests. Here, we analyzed how the success of restoration plantings may be improved through the choice or manipulation of microsites in P. uviferum forests on Chiloé Island in North Patagonia. For this purpose, we manipulated microtopography in water-logged sites in bogs (mounds, flat terrain, mineral soil) and changed canopy conditions (gaps, semi-open, closed canopy) in upland sites with better drainage. In bogs, there was no significant effect of microtopography on growth and survival of P. uviferum plantings. However, fluorescence measurements indicated lower stress in seedlings established on mounds. Seedlings in upland areas established beneath a nurse canopy had lower mortality and higher relative shoot growth, foliar nutrients, photosynthetic light use efficiency and chlorophyll fluorescence values than those planted in the open. This indicates that seedlings of the slow growing P. uviferum can tolerate extremely wet conditions, yet suffer from stress when grown in the open. Here, the removal of canopy appeared to have also removed or reduced mycorrhizal networks for seedlings, leading to poorer nutrition and growth. Based on these results, recommendations for restoration plantings in highly degraded P. uviferum forests are presented. ; p.85-103
    Keywords: Sphagnum ; Chiloé Island ; Conifer Bog Forests ; Seedling Growth ; North Patagonia ; Active Restoration
    ISSN: 19994907
    E-ISSN: 19994907
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  • 10
    Language: English
    In: Biomass and bioenergy, 2012, Vol.46, pp.722-730
    Description: Over-aged coppice forests (older than 40 years) occur all over Europe as a result of the abandonment of traditional harvesting practices during the last 60–100 years. With the increasing demand for bioenergy, there is renewed interest in coppicing, which typically aims at maximizing biomass production. For the sustainable management of these forests, accurate estimates of their biomass potential are needed. Therefore biomass equations for the two most common tree species traditionally managed in Central European coppice systems were developed in this study. In total, 24 oak (Quercus petraea) and 24 hornbeam (Carpinus betulus) trees from two different, aged coppice stands in Rhineland-Palatinate (southwest Germany) were felled and separated into various biomass compartments which were directly weighed in the field. From every compartment, samples were taken to the laboratory to determine wood density and water content. Based on dendrometric parameters (diameter at breast height (dbh)) and compartment dry mass, allometric equations were developed. Power functions provided the best fits for relationships between dbh and biomass in tree compartments and whole trees (R² = 0.97 and 0.92 for oak and hornbeam, respectively). These allometric equations for oak differ considerably from those developed for trees grown in high forests, pointing to the need to use equations that are specific to silvicultural systems, in this case for aged coppice forests. ; p. 722-730.
    Keywords: Forests ; Quercus Petraea ; Coppicing ; Tree And Stand Measurements ; Equations ; Bioenergy ; Biomass Production ; Allometry ; Wood Density ; Harvesting ; Carpinus Betulus ; Trees ; Water Content ; Silvicultural Systems
    ISSN: 0961-9534
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
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