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Long-term forest carbon storage and structural development as influenced by land-use history and reforestation approachUrbano, Andrea Rose 01 January 2016 (has links)
Temperate forests are an important carbon sink, yet there is uncertainty regarding land-use history effects on biomass accumulation and carbon storage potential in secondary forests. Understanding long-term biomass dynamics is important for managing forests as carbon sinks and for co-benefits such as watershed protection and biodiversity. However there are many unanswered questions regarding these dynamics in northeastern U.S. forests: How have secondary forests of the U.S. Northeast recovered post nineteenth century agricultural abandonment? How has the region's extensive land-use history influenced long-term structural development and aboveground carbon storage? To answer these questions, we employed a longitudinal study based on twelve years of empirical data (2001-2013) from the Marsh-Billings-Rockefeller (MBR) National Historical Park in Woodstock, VT. MBR Park was the first parcel of land to actively be reforested in the eastern U.S., and as such, its diverse forest mosaic reflects a history of alternate reforestation approaches and varied successional trajectories indicative of secondary forest recovery occurring across the broader northeastern forest landscape. We also used 150 years of documentary data from park management records. This research evaluates the effects of reforestation approaches (planting vs. natural regeneration), management regimes (long-term low-to-intermediate harvest intensities at varied harvest frequencies), and stand development pathways on biomass outcomes. We generated biometrics representative of stand structural complexity, including the H' structural diversity index, and aboveground biomass (live trees, snags, and downed coarse woody debris pools) estimates. Multivariate analyses evaluated the predictive strength of reforestation approach, management history, and site characteristics relative to aboveground carbon pools and stand structural complexity.
Classification and Regression Tree (CART) analysis ranked reforestation approach (plantation or natural regeneration) as the strongest predictor of long-term mean total aboveground carbon storage, while harvest frequency, and stand age were selected as secondary variables. CART ranked forest percent conifer (a metric closely associated with reforestation approach) as the strongest predictor of H' index, while harvest intensity, and harvest frequency were selected as secondary variables. Increases in harvest intensity can significantly reduce aboveground carbon storage. Our results suggest that a variety of long-term recovery pathways converge on high levels of aboveground carbon storage, including both conifer plantations and naturally regenerated hardwood stands, but choice of silvicultural management approach can dramatically alter those trajectories. Importantly, total aboveground biomass (i.e., carbon) co-varied with H' (r2 = 0.25), and thus, our dataset showed a positive relationship between forest carbon storage and structural complexity, supporting the concept of multifunctional forestry emphasizing late-successional habitats.
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Estimativas de biomassa e carbono e indicadores para restauração de florestas secundárias em Paragominas, Pará / Biomass and cabon estimations and ecological indicators for secondary forest restoration in Paragominas, ParáSâmia do Socorro Serra Nunes 13 May 2011 (has links)
Os ecossistemas florestais são considerados reservatórios de carbono e têm sido apontados como alternativas para redução de gases do efeito estufa, principais responsáveis pelas mudanças climáticas globais, devido ao acúmulo de biomassa em seus tecidos durante seu desenvolvimento. Assim, surgiu uma grande demanda por pesquisas que quantifiquem o potencial dos ecossistemas florestais - principalmente as florestas secundárias - em sequestrar carbono da atmosfera e por investimentos em recuperação de áreas degradadas. Desta forma, este estudo tem como objetivo comparar florestas do município de Paragominas, Pará, em seis diferentes estágios de desenvolvimento: uma floresta primária e florestas secundárias com 4, 10, 15, 20 e 25 anos de abandono. A comparação entre as florestas se deu por meio da estimativa de carbono e biomassa, de indicadores ecológicos para fins de restauração florestal e de análises espectrais usando imagens de satélite Landsat. Para isso foi realizado um inventário florestal nas regiões de interesse, utilizando 32 parcelas experimentais. Os dados de DAP e altura coletados no inventário foram utilizados no cálculo de biomassa e carbono por meio de equações alométricas. Dados do inventário também foram utilizados para a elaboração dos indicadores para fins de restauração florestal, baseados nas características funcionais e estruturais das florestas estudadas, como diversidade de espécies, cipós, hábitos de vida, incidência de luz, etc. Após alocação das parcelas nas imagens de satélite Landsat e processamento dos dados, foi possível extrair informações quantitativas para comparar espectralmente as florestas. Para avaliar os indicadores para fins de restauração florestal, foi usada uma análise por componentes principais. Esta análise mostrou uma clara distinção entre as diferentes idades de florestas, sendo que a floresta intacta é mais semenhante às florestas secundárias mais maduras. Para a estimativa de biomassa, as análises mostraram que houve diferença estatística entre a floresta primária e todas as outras classes de floresta secundária quanto à biomassa média por hectare calculada por todas as equações utilizadas no estudo. Além disso, houve um aumento de biomassa com a idade das florestas, para todas as equações, ou seja, quanto mais madura a floresta, maior sua biomassa. As análises estatísticas mostraram que é possível distinguir floresta primária da maioria das classes de idade de floresta secundária utilizando um ou uma combinação de dados espectrais avaliados neste estudo. Imagens-fração, GV and shade, foram mais eficientes em diferenciar as florestas. Os resultados mostraram que é possível usar imagens Landsat para monitorar florestas secundárias e mapear classes de idades. / Forest ecosystems are considered carbon sinks and have been pointed as an alternative for reducing the amount of greenhouse gases in the atmosphere, main drivers of global climate changes, due to biomass accumulation in their tissues during growth. Thus, there is great demand for research to quantify the potential of forest ecosystems - especially regrowing secondary forests - in absorbing carbon from the atmosphere and by investments in forest restoration. Therefore, this study aims to compare forests located in Paragominas, Pará, in six different stages: a primary forest and secondary forests with 4, 10, 15, 20 and 25 years of abandonment. The comparison among forests was made by estimating biomass and carbon, ecological indicators for forest restoration and spectral analysis using Landsat satellite imagery. For that purpose, forest inventories were conducted over regions of interest, at 32 experimental plots. The DBH and height data collected in the inventories were used to calculate biomass and carbon using allometric equations. Inventory data were also used to calculate indicators of forest restoration, based on functional and structural characteristics of the studied forests, such as species diversity, lianas, life habits, incidence of light, etc. After allocation of plots in the Landsat imagery and data processing, it was possible to extract quantitative information to compare forests regarding their spectral signature. To assess indicators for restoration purposes, was used a principal component analysis. The results showed a clear distinction among the different ages of forest, in which intact forest is showed more similarity to mature secondary forests then to young secondary forests. For biomass estimation, the analysis showed that there was statistical difference between the primary forest and all other classes of secondary forest considering the average biomass per hectare calculated for all equations used in the study. Furthermore, there was an increase in biomass with age of forests, for all equations, that is, the older the forest, the greater its biomass. The spectral analysis showed that it is possible to distinguish primary forest from most ages of secondary forests using one or a combination of spectral features evaluated in this study. Fraction images, GV and shade, showed more efficient in separating forest types. These results showed that it is possible to use Landsat imagery spectral features to remotely monitor secondary forest and to map age classes.
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Estimativas de biomassa e carbono e indicadores para restauração de florestas secundárias em Paragominas, Pará / Biomass and cabon estimations and ecological indicators for secondary forest restoration in Paragominas, ParáNunes, Sâmia do Socorro Serra 13 May 2011 (has links)
Os ecossistemas florestais são considerados reservatórios de carbono e têm sido apontados como alternativas para redução de gases do efeito estufa, principais responsáveis pelas mudanças climáticas globais, devido ao acúmulo de biomassa em seus tecidos durante seu desenvolvimento. Assim, surgiu uma grande demanda por pesquisas que quantifiquem o potencial dos ecossistemas florestais - principalmente as florestas secundárias - em sequestrar carbono da atmosfera e por investimentos em recuperação de áreas degradadas. Desta forma, este estudo tem como objetivo comparar florestas do município de Paragominas, Pará, em seis diferentes estágios de desenvolvimento: uma floresta primária e florestas secundárias com 4, 10, 15, 20 e 25 anos de abandono. A comparação entre as florestas se deu por meio da estimativa de carbono e biomassa, de indicadores ecológicos para fins de restauração florestal e de análises espectrais usando imagens de satélite Landsat. Para isso foi realizado um inventário florestal nas regiões de interesse, utilizando 32 parcelas experimentais. Os dados de DAP e altura coletados no inventário foram utilizados no cálculo de biomassa e carbono por meio de equações alométricas. Dados do inventário também foram utilizados para a elaboração dos indicadores para fins de restauração florestal, baseados nas características funcionais e estruturais das florestas estudadas, como diversidade de espécies, cipós, hábitos de vida, incidência de luz, etc. Após alocação das parcelas nas imagens de satélite Landsat e processamento dos dados, foi possível extrair informações quantitativas para comparar espectralmente as florestas. Para avaliar os indicadores para fins de restauração florestal, foi usada uma análise por componentes principais. Esta análise mostrou uma clara distinção entre as diferentes idades de florestas, sendo que a floresta intacta é mais semenhante às florestas secundárias mais maduras. Para a estimativa de biomassa, as análises mostraram que houve diferença estatística entre a floresta primária e todas as outras classes de floresta secundária quanto à biomassa média por hectare calculada por todas as equações utilizadas no estudo. Além disso, houve um aumento de biomassa com a idade das florestas, para todas as equações, ou seja, quanto mais madura a floresta, maior sua biomassa. As análises estatísticas mostraram que é possível distinguir floresta primária da maioria das classes de idade de floresta secundária utilizando um ou uma combinação de dados espectrais avaliados neste estudo. Imagens-fração, GV and shade, foram mais eficientes em diferenciar as florestas. Os resultados mostraram que é possível usar imagens Landsat para monitorar florestas secundárias e mapear classes de idades. / Forest ecosystems are considered carbon sinks and have been pointed as an alternative for reducing the amount of greenhouse gases in the atmosphere, main drivers of global climate changes, due to biomass accumulation in their tissues during growth. Thus, there is great demand for research to quantify the potential of forest ecosystems - especially regrowing secondary forests - in absorbing carbon from the atmosphere and by investments in forest restoration. Therefore, this study aims to compare forests located in Paragominas, Pará, in six different stages: a primary forest and secondary forests with 4, 10, 15, 20 and 25 years of abandonment. The comparison among forests was made by estimating biomass and carbon, ecological indicators for forest restoration and spectral analysis using Landsat satellite imagery. For that purpose, forest inventories were conducted over regions of interest, at 32 experimental plots. The DBH and height data collected in the inventories were used to calculate biomass and carbon using allometric equations. Inventory data were also used to calculate indicators of forest restoration, based on functional and structural characteristics of the studied forests, such as species diversity, lianas, life habits, incidence of light, etc. After allocation of plots in the Landsat imagery and data processing, it was possible to extract quantitative information to compare forests regarding their spectral signature. To assess indicators for restoration purposes, was used a principal component analysis. The results showed a clear distinction among the different ages of forest, in which intact forest is showed more similarity to mature secondary forests then to young secondary forests. For biomass estimation, the analysis showed that there was statistical difference between the primary forest and all other classes of secondary forest considering the average biomass per hectare calculated for all equations used in the study. Furthermore, there was an increase in biomass with age of forests, for all equations, that is, the older the forest, the greater its biomass. The spectral analysis showed that it is possible to distinguish primary forest from most ages of secondary forests using one or a combination of spectral features evaluated in this study. Fraction images, GV and shade, showed more efficient in separating forest types. These results showed that it is possible to use Landsat imagery spectral features to remotely monitor secondary forest and to map age classes.
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Dynamika nadzemní biomasy ostřicového slatiniště / Dynamics of aboveground biomass of a sedge fenHAŠEK, Ladislav January 2015 (has links)
This thesis is part of Project of the Grant Agency of the Czech Republic No P504/11/1151, focused on the role of plants in the balance of carbon dioxide and the other greenhouse gases produced in the ecosystem of a sedge fen, which is situated on the study site Wet Meadows near Třeboň. The thesis deals with the growth dynamics of the dominant sedge, Carex acuta. The samples were taken using the method of successive harvests near the automatic meteorological station of Czech Globe, Academy of Sciences of the Czech Republic. During the growing season nine harvests were accomplished on 25.3, 15.4, 6.5, 5.6., 9.7., 5.8., 9.9., 21.10., 25.11.. On each date eight replicates were taken, i.e., a total of 72 samples within the vegetation season. The seasonal dynamic of the above ground biomass was compared between C. acuta and the other plant species on the experimental area. Both live and dead biomass, was harvested and subsequently sorted to single botanic species, dried, weighed and the values were processed using the MS Excel tables. The seasonal maximum of aboveground biomass of all plant species (both live and dead parts) was found on 9.7. (1452,72 g.m-2). Among plant species the highest values of aboveground biomass were attained by Calamagrostis canescens (1257,93 g.m-2) and C. acuta (1163,49 g.m-2). C. acuta displayed the highest density of all shoots on 15.4 (300 m-2),and the highest average weight of one shoot. The maximum length of the longest live shoot of Carex acuta was very consistent among the measurememnts.
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Dynamika nadzemní biomasy ostřicového slatiniště / Dynamics of aboveground biomass of a sedge fenHOVORKA, František January 2012 (has links)
This thesis is part of Project of the Grant Agency of the Czech Republic No P504/11/1151, focused on the role of plants in the greenhouse gas budget of a sedge fen. The thesis deals with the growth dynamics of the dominant sedge, Carex acuta L., on the study site, Wet Meadows near Třeboň, Czech Republic. The seasonal changes in aboveground biomass were followed using successive harvests during vegetation seasons of 2010 and 2011. The seasonal maximum of aboveground biomass of Carex acuta L. (both live and dead parts) was 321,44 g.m-2 and 357,97 g.m-2 in 2010 and 2011, respectively. The seasonal maximum of total aboveground biomas sof all species was 558,22 g.m-2 and 522,38 g.m-2 in 2010 and 2011, respectively. The seasonal maximum of shoot density was 485 ks.m-2 and 435 ks.m-2 in 2010 and 2011, respectively.
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Podzemní biomasa rákosu obecného (Phragmites australis) na vegetační kořenové čistírně / Below-ground biomass of the common reed (Phragmites australis) in a constructed wetland used for wastewater treatmentMOULISOVÁ, Lenka January 2010 (has links)
My thesis is a part of the project GACR 206/06/0058 Monitoring of selected heavy metals and risk elements in a wastewater cleaning process in artificial wetlands. The goal is to evaluate temporal and spatial variability of underground biomass of Phragmites australis in the artificial wetland used for wastewater treatment in Slavošovice. The destructive method was used for the sampling. The aboveground biomass was determined from six samples taken at the inflow and six samples at the outflow. The belowground biomass (in 2008) was estimated from two samples taken at the inflow and two samples at the outflow. In 2009, the belowground biomass was determined from six samples taken from the inflow and six samples from the outflow. The analysis of the root structure was determined from 12 samples collected at the inflow and 12 samples of the outflow. The mean total aboveground biomass reached 1039 g.m-2 at the inflow and the 1749 g.m-2 at the outflow. Average total belowground biomass in 2009 reached the inflow 1718 g.m-2 and 1562 g.m-2 at the outflow. The average total length of roots growing from one node to was 284,7 m.m-2 and 324,9 m.m-2 in the inflow and outflow part, respectively. Average specific root length of the inflow was 2589,5 cm.g-1 and the outflow 2956,9 cm.g-1. The average total length of roots reaching the inflow of two kilometers and three kilometers of inflow.
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Carbon Fluxes and Pools in a Montane Rainforest in Sulawesi, IndonesiaHeimsch, Florian 25 March 2021 (has links)
No description available.
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Estimation of Nutrient Exports Resulting from Thinning and Intensive Biomass Extraction in Medium-Aged Spruce and Pine Stands in Saxony, Northeast Germany.Knust, Christine, Feger, Karl-Heinz 27 March 2017 (has links) (PDF)
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.
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Relação entre estoque de carbono acima do solo e produção de cacau em sistemas agroflorestais de cacau em São Félix do Xingu - PA, Brasil / Relationship between aboveground carbon stock and cocoa production in cocoa agroforestry system in São Félix do Xingu - PA, BrazilBonamico, Marco Araujo 25 May 2017 (has links)
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.
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Mensuração da biomassa e construção de modelos para construção de equações de biomassa / Biomass measurement and models selection for biomass equationsVismara, Edgar de Souza 07 May 2009 (has links)
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.
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