Submitted by Mariana Dornelles Vargas (marianadv) on 2015-03-26T14:22:21Z No. of bitstreams: 1 determinantes_variacao.pdf: 908319 bytes, checksum: 62b3232a58e65bb0e1abb6ef44b5c2bc (MD5) / Made available in DSpace on 2015-03-26T14:22:21Z (GMT). No. of bitstreams: 1 determinantes_variacao.pdf: 908319 bytes, checksum: 62b3232a58e65bb0e1abb6ef44b5c2bc (MD5) Previous issue date: 2011-02-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Uma variedade de fatores ambientais e bióticos afeta a produtividade florestal e determina o acúmulo de biomassa. Em ecossistemas florestais, o aumento da produtividade primária propicia o aumento da biomassa vegetal e consequentemente o aumento do carbono orgânico estocado. Dentre os fatores que influenciam a produção de biomassa, podemos citar temperatura, pluviosidade, tipo de solo, composição florística e regime de distúrbios. Nesse sentido, há o consenso entre pesquisadores de que o aumento da temperatura, a homogeneidade do regime de chuvas e solos férteis aumentam a produtividade e possibilitam um maior acúmulo de biomassa. Além disso, diversos autores propõem que riqueza e diversidade de espécies teriam efeito positivo sobre a biomassa, pois aumentariam a eficiência no uso dos recursos. Os objetivos deste estudo foram avaliar as variáveis que afetam a biomassa florestal viva acima do solo (BAS) na região subtropical do sul do Brasil, além de analisar a distribuição espacial das estimativas de biomassa em escala regional. O estudo foi realizado em Florestas Subtropicais Úmidas do sul do Brasil, classificadas como Florestas Latifoliadas (FL) e Florestas Mistas de Coníferas e Latifoliadas (FM). Um total de 38 parcelas de 1 ha foram selecionadas e todas as árvores com DAP ≥ 9,5 cm foram incluídas para as estimativas de biomassa. Valores de BAS foram obtidos utilizando equações alométricas já publicadas na literatura. As variáveis ambientais (altitude, precipitação, temperatura e tipo de solo) foram obtidas da literatura e as variáveis bióticas (densidade e diversidade) foram calculadas a partir da base de dados. Para o conjunto total de dados, a BAS média foi de 194,3 ± 116,8 Mg ha-1 (média ± DP) e a densidade média de carbono foi de 97,2 ± 58,4 MgC ha-1. As estimativas entre tipos florestais diferiram entre si (t= -4,598; p<0,001): a BAS média foi inferior em FL (AGBFL = 118,0 ± 58,4 Mg ha-1) quando comparada a FM (AGBFM = 249,8 ± 118,1 Mg ha-1). A análise de componentes principais executou de forma satisfatória a redução da base de dados de clima e de solo. A regressão múltipla explanatória explicou 49,8% da variação na BAS (Ylog biomassa = 0,03(0,49)xraiz densidade + 0,11(0,36)x eixo latitudinal - 0,22(-0,85)xeixo altitudinal - 0,03(-0,36)xdiversidade - 0,09(-0,35)xeixo matéria orgânica + 1,66; F5,32=8,34; p<0,001; r2=0,498). A altitude contribuiu mais para o modelo do que qualquer outra variável. Não foi encontrada dependência espacial entre as parcelas. Os resultados do nosso estudo mostram uma relação negativa entre biomassa acima do solo e altitude. Assim, valores elevados de BAS estão localizados em altitudes mais elevadas e sujeitos a temperaturas amenas e frequentes chuvas mensais. Parece haver uma contribuição importante da conífera Araucaria angustifolia nas parcelas de FM, visto que árvores de grande porte da espécie foram encontradas em inúmeras unidades amostrais. Florestas subtropicais parecem ser de grande interesse para o sequestro de carbono, especialmente em áreas de Florestas Mistas. No Brasil, a espécie de conífera ameaçada de extinção A. angustifolia compõe florestas com alta diversidade (Florestas com Araucária), com grande potencial de acúmulo de biomassa e sequestro de carbono, enfocando ainda mais a importância de conservação deste ecossistema. / A variety of environmental and biotic factors affect forest productivity and determines biomass accumulation. In forest ecosystems, the increase in primary productivity results in an increase in plant biomass and consequently elevates storage of organic carbon. Among the factors that influence biomass production, we should mention temperature, rainfall, soil type, floristic composition and disturbance regimes. It is widely accepted among researchers that increasing temperature, rainfall homogeneity and fertile soils increase productivity and enable higher biomass accumulation. Moreover, many authors indicate that species richness and diversity have a positive effect on biomass, because of the higher efficiency on resource use. The objectives of the study were to evaluate the variables affecting live aboveground forest biomass (AGB) in Subtropical Southern Brazil and analyze the spatial distribution of biomass estimates. The study was performed in Subtropical Moist Forests of Southern Brazil, classified as Broadleaf Forests (BF) and Mixed Coniferous-Broadleaf Forests (MF). A total of 38 1-ha plots were selected and all trees with DBH ≥ 9.5 cm were included for biomass estimation. Values for AGB were obtained using published alometric equations. Environmental variables (elevation, rainfall, temperature and soils) were obtained from the literature and biotic variables (density and diversity) were calculated from the data set. For the total number of plots, mean AGB was 194.3 ± 116.8 Mg ha-1 (mean ± SD) and mean carbon density 97.2 ± 58.4 MgC ha-1. Estimates differed between forest types (t= -4.598; p<0.001): mean AGB was lower in BF (AGBBF = 118.0 ± 58.4 Mg ha-1) when compared to MF (AGBMF = 249.8 ± 118.1 Mg ha-1). Principal component analysis performed well in summarizing climate and soil data sets. The explanatory multiple regression explained 49.8% of the variation in AGB (Ylog biomass = 0.03(0.49)xsqroot density + 0.11(0.36)x latitudinal axis - 0.22(-0.85)xelevation axis ? 0.03(-0.36)xdiversity - 0.09(-0.35)xorganic matter axis + 1.66; F5,32=8.34, p<0.001; r2=0.498). Elevation contributed more to the model than any other variable. There was no spatial dependency found between plots. The results from our study showed a negative relationship between aboveground biomass and elevation. Therefore, higher values of AGB are located at higher altitudes and subjected to cooler temperatures and frequent monthly rainfall. There seems to be an important contribution of the coniferous species Araucaria angustifolia in MF plots, since large trees of this species were found in many of the samples. Subtropical forests appear to be of great interest for carbon sequestration, especially in areas of Mixed Coniferous-Broadleaf Forests. In Brazil, the endangered coniferous species A. angustifolia is part of a high diversity forest (Araucaria Forest), with great potential for biomass accumulation and carbon sequestration, emphasizing the importance in conserving this ecosystem.

Woodlands constitute the subsistence base of the majority of people in the Sudano-Sahelian zone (SSZ), but low availability of in situ data on vegetation structure and composition hampers research and monitoring. This thesis explores the utility of remote sensing for mapping and analysing vegetation, primarily trees, in the SSZ. A comprehensive literature review was first conducted to describe how the application of remote sensing has developed in the SSZ between 1975 and 2014, and to identify important research gaps. Based on the gaps identified in the literature review, the capabilities of two new satellite systems (WorldView-2 and Landsat 8) for mapping woodland structure and composition were tested in an area in central Burkina Faso. The results shows that WorldView-2 represents a useful data source for mapping individual trees: 85.4% of the reference trees were detected in the WorldView-2 data and tree crown area was estimate with an average error of 45.6%. In addition, WorldView-2 data produced high classification accuracies for five locally important tree species. The highest overall classification accuracy (82.4%) was produced using multi-temporal WorldView-2 data. Landsat 8 data proved more suitable for mapping tree canopy cover as compared to aboveground biomass in the woodland landscape. Tree canopy cover and aboveground biomass was predicted with 41% and 66% root mean square error, respectively, at pixel level. This thesis demonstrates the potential of easily accessible data from two satellite systems for mapping important tree attributes in woodland areas, and discusses how the usefulness of remote sensing for analyzing vegetation can be further enhanced in the SSZ. / Merparten av befolkningen i Sudano-Sahel zonen (SSZ) är beroende av naturresurser och ekosystemtjänster från woodlands (öppen torrskog) för att säkra sin försörjning. Tillgången av fältmätningar av vegetationens struktur och sammansättning är mycket låg i detta område, vilket utgör ett problem för forskning och miljöövervakning. Denna avhandling undersöker nyttan av fjärranalys för att kartlägga och analysera vegetation, främst träd, i SSZ. En omfattande litteraturöversikt genomfördes först för att undersöka hur tillämpningen av fjärranalys har utvecklats i SSZ mellan 1975 och 2014, samt att identifiera viktiga forskningsluckor. Några av de luckor som konstaterades i litteraturgenomgången låg till grund för de följande studierna där två nya satellitsystem (Worldview-2 och Landsat 8) utvärderades för deras användbarhet att kartlägga trädtäckets struktur och artsammansättning i ett woodland-område i centrala Burkina Faso. Resultaten visar att Worldview-2 är en värdefull datakälla för kartering av enskilda träd: 85.4% av referensträden detekterades och trädkronornas storlek uppskattades med ett medelfel av 45.6%. Worldview-2-data producerade även hög klassificeringsnoggrannhet för de fem lokalt viktigaste trädslagen. Den högsta noggrannheten (82.4%) uppnåddes med multi-temporal Worldview-2-data. Landsat 8 data visade sig mer lämpade för kartering av krontäcke, jämfört med biomassa. Medelfelet för karteringen var 41% för krontäcke och 66% för biomassa, på pixelnivå. Avhandlingen visar att lättillgängliga data från två satellitsystem är användbara för kartläggning av viktiga trädattribut i woodlands, samt diskuterar hur nyttan av fjärranalys för vegetationsanalys kan ökas ytterligare i SSZ.

Annotation This thesis is part of Project of the Grant Agency of the Czech Republic No. P504/11/1151 (Role of plants in the greenhouse gas budget of a sedge fen) aims at estimating the turnover of aboveground biomass of Carex acuta L. in a flooded part of the Wet Meadows near Třeboň. The biomass turnover was estimated using both destructive and non-destructive types of measurement and was assessed separately for generative and vegetative tillers, which markedly differ in their life cycles. Vegetative tillers last throughout the vegetation season. Generative tillers have a fast development at the beginning of the vegetatin season but die out soon after seed development. They disapper from the stand in mid-July. Vegetative shoots reached their maximum aboveground biomass at the end of June. The average dry weight of all leaves produced so far was 1,51 g per tiller and the average dry weight of all aboveground biomass produced per tiller was 2,28 g. The turnover coefficient was 1,39 year-1 and 1,01 year-1 for leaves and whole tillers, respectively. Also generative shoots reached their maximum aboveground biomass at the end of June. The average dry weight of aboveground biomass produced so far was 1,95 g per tiller. The turnover coefficient was 1, 38 year-1and 1,10 year-1.

Human pressure on forest resources increased significantly during the past decades through land use and land use change, especially in the tropics where forest clearing is a major source of CO2 release in the atmosphere. Consequently, forests are the focus of international environmental policies and discussions aiming to reduce emissions from deforestation and forest degradation (i.e. REDD+). The capacity of participating countries to regularly provide accurate forests C stocks measurements at a national scale thus represents an important challenge to address. In dense forests, generally only the above ground biomass (AGB) is measured as it accounts for more than 50% of total C stocks. However, important gaps remain at each scale of measurement, i.e. from felled tree to regional mapping, with the resulting errors propagation through these different scales being probably the most concerning issue.<p><p>In the present work, we propose to address these issues by using a multi-scale approach in order to improve our global understanding of AGB variations in dense tropical forests of Central Africa. In particular, we studied (i) forest AGB prediction from remote-sensing textural analysis, (ii) the potential role of largest trees as predictor of the entire forest-stand AGB and (iii) intra- and inter-individual radial variation of wood specific gravity (WSG, i.e. oven-dry mass divided by its green volume) and its potential consequences on the estimation of the AGB of the tree. <p>First, we analyzed the potential use of textural analysis to predict AGB distribution based on very high spatial resolution satellite scenes. In particular, we used the Fast Fourier Transform Ordination (FOTO) method to predict AGB from heterogeneous forest stands of the Democratic Republic of the Congo (DRC). Here, based on 26 ground plots of 1-ha gathered from the field, plus a successful combination of Geoeye and Quickbird contrasted scenes, we were able to predict and to map AGB with a robust model (R² = 0.85; RMSE = 15%) based on textural gradients. <p>Secondly, the research of AGB indicators was focused on the dissection of the role played by largest trees. Here we found largest trees not only hold large share of forest carbon stock but they contain the print of most of forest-stand structure and diversity. Using a large dataset from western Cameroon to eastern DRC, we developed a non-linear model to predict forest carbon stock from the measurement of only a few large trees. We found the AGB of the 5 % largest stems allow to predict the AGB of the entire forest-stand yielding an R² of 0.87 at a regional scale. Focusing on largest trees species composition, we also showed only 5 % of species account for 50 % of total AGB.<p>In the end, we investigated inter- and intra-individual WSG variations. Despite recognized inter- and intra-specific variations along the radial axis, their ecological determinants and their consequences on trees aboveground biomass assessments remain understudied in tropical regions. To our knowledge, it has never been investigated in Africa. Using a 3-D X-Ray scanner, we studied the radial WSG variation of 14 canopy species of DRC tropical forests. Wood specific gravity variance along the radial profile was dominated by differences between species intercepts (~76%), followed by the differences between their slope (~11%) and between individual cores intercept (~10%). Residual variance was minimal (~3%). Interestingly, no differences were found in the comparison of mean WSG observed on the entire core and the mean WSG at 1-cm under the bark (intercept ~0; coefficient = 1.03). In addition, local values of WSG are strongly correlated with mean value in the global data base at species level. <p><p>I deeply believe these results favor the development of promising tools to map and to estimate accurately the AGB of tropical forest-stands. The information provided by largest trees on the entire forest-stand is particularly interesting both for developing new sampling strategies for carbon stocks monitoring and to characterize tropical forest-stand structure. In particular, our results should provide the opportunity to decrease current sampling cost while decreasing its main related uncertainties, and might also favor an increase of the current sampling coverage. <p> / Doctorat en Sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Considerando os desafios do aumento da pressão antrópica, das emissões de gases do efeito estufa, das mudanças climáticas e do crescimento da área de desmatamento acumulado na Amazônia - incentivado pelo avanço da fronteira agropecuária - é necessário encontrar formas alternativas de produção agrícola que apresentem potencial mitigatório. A presente pesquisa coletou dados em sistemas agroflorestais de cacau (Theobroma cacao L.) (SAF-cacau) em 40 parcelas de 20 x 50 metros (1000 m2) amostradas em 20 pequenas propriedades, no município de São Félix do Xingu, no sudeste do Pará, objetivando encontrar a relação entre o estoque de carbono acima do solo de indivíduos arbóreos e a produção de cacau, buscando sua relação ótima. Para melhor compreensão da relação carbono x produção também foram estimadas variáveis que influenciam na produtividade do cacaueiro, como fertilidade do solo, entrada de luz no sistema, e manejo. Para tanto, os métodos utilizados na coleta dos dados foram: (1) estimativa da altura do dossel; (2) medida da circunferência à altura do peito (CAP) dos indivíduos arbóreos de sombreamento; (3) medida da circunferência a 30 cm do solo dos cacaueiros; (4) amostra do solo em duas profundidades - 0-10 cm e 20-30 cm; (5) cálculo do Índice de Cobertura de Dossel (ICD) utilizando densiômetro florestal; (6) estimativa da produção de cacau por contagem de frutos e (7) levantamento por meio de questionário semiestruturado das condições socioeconômicas e percepção dos agricultores sobre seu plantio, além do manejo dado a ele. Os dados referentes ao SAFs-cacau foram analisados com uso de Análise de Componentes Principais e regressões polinomiais, de forma a compreender de que forma as variáveis se relacionavam. Como resultado, constatamos que os SAFs-cacau possuem em média 14,35 ± 4,9 anos de plantio, produzem em média 354,32 ± 335,52 kg de amêndoa seca de cacau.ha-1.ano-1 estocando em média 13,53 ± MgC.ha-1 em cacaueiros, 16,05 ± 23,56 MgC.ha-1 em árvores de sombreamento, compondo um total de 29,58 ± 24,37 MgC.ha-1 de biomassa arbórea acima do solo, sob índice de cobertura de dossel (ICD) acima do cacaueiro médio de 27,85 ± 22,84. Foi averiguado que quando considerada a relação renda por área, a cultura do cacau provê renda até 8 vezes maior que a pecuária. As análises indicam uma grande variedade de formas de manejo, resultando em grande variação dos dados amostrados, inclusive produtividade. A parcela com melhor relação carbono/produtividade, com produtividade acima da média local, apresentou carbono de sombreamento de 17,92 MgC.ha-1, estoques de carbono acima do solo em cacaueiros de 11,53 MgC.ha-1 e carbono total acima do solo de 29,45 MgC.ha-1, com produtividade de 501,28 kg de amêndoa seca/ano e ICD de 48,83%. As análises de solo mostraram pH, fósforo, magnésio e cálcio em média fora do desejável para cultivo do cacaueiro. As regressões polinomiais indicam que há potencial para enriquecer os SAFs-cacau com árvores de sombreamento de uso econômico, compensando a perda de renda advinda da menor produtividade do cacaueiro, além de prover serviços ambientais. / Considering the challenges posed by the increasing anthropogenic pressure, greenhouse gas emissions, climate change and the growth of deforestation in the Amazon - encouraged by the advancement of the agricultural and livestock frontier - it is necessary to find alternative forms of agricultural production that has potential for mitigation. The present study collected data on 20 cocoa (Theobroma cacao L.) agroforestry systems (AFS), 2 plots of 20 x 50 meters (1000 m2) sampled in 20 small farms in the municipality of São Félix do Xingu, in the southeast of the Pará, aiming to find the relation between the aboveground carbon stocks and cocoa production, searching for its optimal relation. For a better understanding of the carbon x production relationship, we also estimated variables that influence cacao yield, such as soil fertility, light input into the system, and management. To do so, the methods used in data collection were: (1) canopy height estimation; (2) measurement of the circumference at the chest height (CAP) of shade trees; (3) measurement of the circumference at 30 cm of the soil of cacao trees; (4) soil sample at two depths: 0-10 cm and 20-30 cm; (5) calculation of the Canopy Coverage Index (DCI) using a forest densitometer; (6) estimation of cocoa yield by fruit counts and (7) semi-structured questionnaire survey of socioeconomic conditions and farmers\' perception of their AFS, in addition to the management given to them. The data concerning cocoa-based AFs were analyzed using Principal Component Analysis and polynomial regressions, in order to understand how the variables were related to each other. As a result, we found that cocoa SAFs have a mean of 14.35 ± 4.9 years of planting, producing on average 354.32 ± 335.52 kg of dry cocoa beans.ha-1.year-1 stocking on average 13.53 ± MgC.ha-1 in cacao trees, 16.05 ± 23.56 MgC.ha-1 in shading trees, composing a total of 29.58 ± 24.37 MgC.ha-1 of aboveground tree biomass , under canopy cover index (ICD) (measured above the cocoa tree) of 27.85 ± 22.84. It was verified that when considering the relation income by area, the cocoa AFS provides income up to 8 times greater than livestock. The analyzes indicate a wide variety of management methods, resulting in a large variation of the data sampled, including yield. The plot with best carbon/yield relation and with yield above the local average, showed shading tree carbon stocks of 17.92 MgC.ha-1, aboveground carbon stocks in cacao trees of 11.53 MgC.ha-1 and total aboveground carbon of 29.45 MgC.ha-1, yielding 501.28 kg of dried cocoa beans/year and ICD of 48.83%. Soil analyzes showed soils with averages of pH, phosphorus, magnesium and calcium below recommended values for cacao cultivation. Polynomial regressions indicate that there is potential to enrich cocoa-based AFS with shading trees for economic use, compensating for the loss of income from lower cocoa yield, as well as providing environmental services.

O interesse pela quantificação da biomassa florestal vem crescendo muito nos últimos anos, sendo este crescimento relacionado diretamente ao potencial que as florestas tem em acumular carbono atmosférico na sua biomassa. A biomassa florestal pode ser acessada diretamente, por meio de inventário, ou através de modelos empíricos de predição. A construção de modelos de predição de biomassa envolve a mensuração das variáveis e o ajuste e seleção de modelos estatísticos. A partir de uma amostra destrutiva de de 200 indivíduos de dez essências florestais distintas advindos da região de Linhares, ES., foram construídos modelos de predição empíricos de biomassa aérea visando futuro uso em projetos de reflorestamento. O processo de construção dos modelos consistiu de uma análise das técnicas de obtenção dos dados e de ajuste dos modelos, bem como de uma análise dos processos de seleção destes a partir do critério de Informação de Akaike (AIC). No processo de obtenção dos dados foram testadas a técnica volumétrica e a técnica gravimétrica, a partir da coleta de cinco discos de madeira por árvore, em posições distintas no lenho. Na técnica gravimétrica, estudou-se diferentes técnicas de composição do teor de umidade dos discos para determinação da biomassa, concluindo-se como a melhor a que utiliza a média aritmética dos discos da base, meio e topo. Na técnica volumétrica, estudou-se diferentes técnicas de composição da densidade do tronco com base nas densidades básicas dos discos, concluindo-se que em termos de densidade do tronco, a média aritmética das densidades básicas dos cinco discos se mostrou como melhor técnica. Entretanto, quando se multiplica a densidade do tronco pelo volume deste para obtenção da biomassa, a utilização da densidade básica do disco do meio se mostrou superior a todas as técnicas. A utilização de uma densidade básica média da espécie para determinação da biomassa, via técnica volumétrica, se apresentou como uma abordagem inferior a qualquer técnica que utiliza informação da densidade do tronco das árvores individualmente. Por fim, sete modelos de predição de biomassa aérea de árvores considerando seus diferentes compartimentos foram ajustados, a partir das funções de Spurr e Schumacher-Hall, com e sem a inclusão da altura como variável preditora. Destes modelos, quatro eram gaussianos e três eram lognormais. Estes mesmos sete modelos foram ajustados incluindo a medida de penetração como variável preditora, totalizando quatorze modelos testados. O modelo de Schumacher-Hall se mostrou, de maneira geral, superior ao modelo de Spurr. A altura só se mostrou efetiva na explicação da biomassa das árvores quando em conjunto com a medida de penetração. Os modelos selecionados foram do grupo que incluíram a medida de penetração no lenho como variável preditora e , exceto o modelo de predição da biomassa de folhas, todos se mostraram adequados para aplicação na predição da biomassa aérea em áreas de reflorestamento. / Forest biomass measurement implies a destructive procedure, thus forest inventories and biomass surveys apply indirect procedure for the determination of biomass of the different components of the forest (wood, branches, leaves, roots, etc.). The usual approch consists in taking a destructive sample for the measurment of trees attributes and an empirical relationship is established between the biomass and other attributes that can be directly measured on standing trees, e.g., stem diameter and tree height. The biomass determination of felled trees can be achived by two techniques: the gravimetric technique, that weights the components in the field and take a sample for the determination of water content in the laboratory; and the volumetric technique, that determines the volume of the component in the field and take a sample for the determination of the wood specific gravity (wood basic density) in the laboratory. The gravimetric technique applies to all components of the trees, while the volumetric technique is usually restricted to the stem and large branches. In this study, these two techniques are studied in a sample fo 200 trees of 10 different species from the region of Linhares, ES. In each tree, 5 cross-sections of the stem were taken to investigate the best procedure for the determination of water content in gravimetric technique and for determination of the wood specific gravity in the volumetric technique. Also, Akaike Information Criterion (AIC) was used to compare different statistical models for the prediction o tree biomass. For the stem water content determination, the best procedure as the aritmetic mean of the water content from the cross-sections in the base, middle and top of the stem. In the determination of wood specific gravity, the best procedure was the aritmetic mean of all five cross-sections discs of the stem, however, for the determination of the biomass, i.e., the product of stem volume and wood specific gravity, the best procedure was the use of the middle stem cross-section disc wood specific gravity. The use of an average wood specific gravity by species showed worse results than any procedure that used information of wood specific gravity at individual tree level. Seven models, as variations of Spurr and Schumacher-Hall volume equation models, were tested for the different tree components: wood (stem and large branches), little branches, leaves and total biomass. In general, Schumacher-Hall models were better than Spurr based models, and models that included only diameter (DBH) information performed better than models with diameter and height measurements. When a measure of penetration in the wood, as a surrogate of wood density, was added to the models, the models with the three variables: diameter, height and penetration, became the best models.

A growing interest in using forest biomass for bioenergy generation may stimulate intensive harvesting scenarios in Germany. We calculated and compared nutrient exports of conventional stem only (SO), whole tree without needles (WT excl. needles), and whole tree (WT) harvesting in two medium aged Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) stands differing in productivity, and related them to soil nutrient pools and fluxes at the study sites. We established allometric biomass functions for each aboveground tree compartment and analyzed their nutrient contents. We analyzed soil nutrient stocks, estimated weathering rates, and obtained deposition and seepage data from nearby Level II stations. WT (excl. needles) and WT treatments cause nutrient losses 1.5 to 3.6 times higher than SO, while the biomass gain is only 1.18 to 1.25 in case of WT (excl. needles) and 1.28 to 1.30 in case of WT in the pine and spruce stand, respectively. Within the investigated 25-year period, WT harvesting would cause exports of N, K+, Ca2+, and Mg2+ of 6.6, 8.8, 5.4, and 0.8 kg·ha−1 in the pine stand and 13.9, 7.0, 10.6, and 1.8 kg·ha−1 in the spruce stand annually. The relative impact of WT and WT (excl. needles) on the nutrient balance is similar in the pine and spruce stands, despite differences in stand productivities, and thus the absolute amount of nutrients removed. In addition to the impact of intensive harvesting, both sites are characterized by high seepage losses of base cations, further impairing the nutrient budget. While intensive biomass extraction causes detrimental effects on many key soil ecological properties, our calculations may serve to implement measures to improve the nutrient balance in forested ecosystems.

No description available.

No description available.

Plant functional traits (plant height, aboveground biomass, R/S ratio, specific leaf area, leaf dry matter content, specific root length and arbuscular mycorrhizal infection) were measured for several grassland plant species growing under different soil fertility conditions in a greenhouse and a field experiments. Traits` response to nutrient addition and the differences in traits among species and between forbs and grasses were studied. Results from the greenhouse and the field experiment were compared.