A busca do manejo sustentável tem promovido estudos em microbacias hidrográficas através do monitoramento das atividades florestais, procurando a melhor forma de manejo do solo, de modo a diminuir impacto ambiental e ao mesmo tempo manter a produtividade do sítio e a rentabilidade econômica. Neste contexto, com o intuito de obter informações sobre os impactos provocados pelas atividades de exploração e preparo do solo realizadas em áreas reflorestadas com Pinus taeda, o presente trabalho consiste na análise de dados do monitoramento do manejo florestal em duas microbacias adjacentes, denominadas de Microbacia Experimental da Lage e a Microbacia Experimental do Banhado, sendo esta última mantida inalterada durante o período de estudo. A evapotranspiração (ET) média para o período antes do corte foi de 1388,6mm para a microbacia da Lage e 1362,7mm para a microbacia do Banhado, representando 91% e 89% da precipitação, respectivamente. No primeiro ano após o corte, os valores médios estimados foram de: 1012,1mm, representando 77% da precipitação para a Lage e 1145,9mm (88% da precipitação) para o Banhado. No segundo ano após o corte a ET da microbacia da Lage manteve-se no patamar de 78% da precipitação. A maior parte da biomassa presente na microbacia estava contida no lenho, seguido dos galhos, casca e acículas, sendo que 277,57 ton. ha -1 foram retiradas na forma de toras (lenho e casca) e 80,00 ton. ha -1 foram mantidas no campo (acículas e galhos). A colheita da madeira foi responsável pela retirada de: 487,11 kg ha -1 de N; 5,80 kg ha -1 de P; 117,14 kg ha -1 de K; 314,58 kg ha -1 de Ca e 287,19 kg ha -1 de Mg. A ciclagem biogeoquímica demonstrou balanço negativo para todos os elementos analisados, sendo que o nitrogênio foi o elemento que teve maior perda, estando esta perda diretamente relacionada com a exportação através da biomassa. A ciclagem geoquímica, avaliada depois do corte, mostrou balanço negativo somente para o Mg, apresentando perda de 1,21 kg ha -1 , e balanço positivo para N, P, K, Ca. / The search for sustainable forest management has result in several monitoring studies in experimental catchments, aimed at obtaining best management practices and minimizing environmental impacts. The present study was developed with the purpose of identifying hydrological indicators which could be used for the monitoring of harvesting activities of Pinus taeda plantations in two experimental catchments : Lage and Banhado. The Lage catchment was used as the treatament catchment (clearcutting harvesting) and the Banhado catchment remained undisturbed as a control. Result showed an annual evapotranspiration of 1388,6 mm for the Lage catchment and 1362,7 mm for the Banhado during the pre-treatment period. After clearcutting, annual evapotranspiration declined to 1012,1 mm for the treated catchment and 1145,9 mm for the control catchment. In terms of biogeochemistry results, the greatest proportion of the aboveground biomass was in the wood compartment (278,57 ton.ha -1 ), against 80 ton.ha -1 of leaves and small branches, wich remained in the fiel. Harvesting wood biomass was responsible for the following exportation of nutrients from the catchment soil: 487,11 kg ha -1 de N; 5,80 kg ha -1 de P; 117,14 kg ha -1 de K; 314,58 kg ha -1 de Ca e 287,19 kg ha -1 de Mg. Biogeochemical budgets was negative for all studied nutrients. Catchment geochemical budget in the pos-treatment period was negative only for Mg, with a net loss 1,21kgha -1 , and positive for N, P, K and Ca.

This thesis explored the impacts of forest harvesting on gaseous elemental mercury emissions from forest soils in both field and laboratory studies, through novel use of enriched mercury isotope tracers. Forest floor Hg emissions, sourced from legacy deposition, increased proportionally to the vegetation quantity removed, with biomass harvesting most exacerbating emissions. Contemporary Hg deposition did not appear to be influenced by harvesting. Some of the tracer was rapidly lost to the atmosphere (~8%), but most was sequestered within the soil. Two regimes facilitating Hg emissions were observed in low-light conditions. Under extremely dry conditions deeper Hg sources (> 2cm depth) were as equally susceptible to emission as shallower sources. Following wetting to field capacity, emissions were elevated only from shallow sources, likely as a result of upward capillary transport. Impacts of vegetation removal and dry fluxes are previously uncharacterized and may constitute large additional sources to regional atmospheric Hg cycling.

This thesis explored the impacts of forest harvesting on gaseous elemental mercury emissions from forest soils in both field and laboratory studies, through novel use of enriched mercury isotope tracers. Forest floor Hg emissions, sourced from legacy deposition, increased proportionally to the vegetation quantity removed, with biomass harvesting most exacerbating emissions. Contemporary Hg deposition did not appear to be influenced by harvesting. Some of the tracer was rapidly lost to the atmosphere (~8%), but most was sequestered within the soil. Two regimes facilitating Hg emissions were observed in low-light conditions. Under extremely dry conditions deeper Hg sources (> 2cm depth) were as equally susceptible to emission as shallower sources. Following wetting to field capacity, emissions were elevated only from shallow sources, likely as a result of upward capillary transport. Impacts of vegetation removal and dry fluxes are previously uncharacterized and may constitute large additional sources to regional atmospheric Hg cycling.

Submitted by Leandro Ruiz Machado (leandromachado@columbia.com.br) on 2014-03-06T01:20:13Z No. of bitstreams: 1 Dissertação_ V15_20140305 - Versão Final.pdf: 1843274 bytes, checksum: eee08685c0f2ab2bfb6c985bf7585b12 (MD5) / Rejected by Suzinei Teles Garcia Garcia (suzinei.garcia@fgv.br), reason: Prezado Leandro Ruiz, A ficha catalográfica falta o número do CDU. Link abaixo para solicitar a ficha. http://bdigital.bibliotecas.fgv.br/ficha_catalografica Att. Suzi 3799-7876 on 2014-03-06T14:08:14Z (GMT) / Submitted by Leandro Ruiz Machado (leandromachado@columbia.com.br) on 2014-03-07T19:48:38Z No. of bitstreams: 1 Dissertação_ V15_20140305 - Versão Final.pdf: 1859188 bytes, checksum: 99388b1185ce2ee447c33ca0411f6959 (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia (suzinei.garcia@fgv.br) on 2014-03-10T11:52:56Z (GMT) No. of bitstreams: 1 Dissertação_ V15_20140305 - Versão Final.pdf: 1859188 bytes, checksum: 99388b1185ce2ee447c33ca0411f6959 (MD5) / Made available in DSpace on 2014-03-10T11:55:08Z (GMT). No. of bitstreams: 1 Dissertação_ V15_20140305 - Versão Final.pdf: 1859188 bytes, checksum: 99388b1185ce2ee447c33ca0411f6959 (MD5) Previous issue date: 2014-02-07 / O objetivo deste trabalho foi dimensionar o sistema de corte, carregamento e transporte do eucalipto (CCT) para uma empresa florestal localizada no Oeste Baiano com a finalidade de processar a madeira para queima como biomassa. O sistema considerado foi o chamado 'Americano', que conta com o feller-buncher (corte), o skidder (arraste), o processador florestal (processamento), o carregador florestal (carregamento e descarregamento) e o caminhão (transporte). Os custos encontrados nos equipamentos envolvidos neste processo foram somados, visando-se identificar o módulo padrão, representado pelo conjunto com a maior produtividade e o menor custo, obtendo-se, desta forma, a maior margem sobre o valor da venda da madeira. Os resultados encontrados indicam que o custo de CCT, a partir do módulo padrão de processamento de madeira de 40.000 m3/mês, oscilou entre 26,60% e 34,36% do valor da madeira entregue ao cliente final, dependendo da região onde a mesma é comercializada. Dessa forma, os resultados encontram-se em níveis médios sugeridos pela literatura. Outro ponto que reforça a importância de se analisar estes custos operacionais, é que entre 65,64% e 74,40% do custo de venda da madeira entregue foi formado no período de 5 a 7 anos (prazo de crescimento médio de uma árvore de eucalipto, dependendo da finalidade da utilização da madeira), enquanto que a diferença é formada em apenas 60 dias, prazo este correspondente ao corte, carregamento e transporte desta madeira até o cliente final. Foi feita a análise de sensibilidade das principais variáveis identificadas. Os resultados revelaram que a distância percorrida de ida e volta para entregar a madeira ao cliente final foi a variável que mais impactou na oscilação do custo final do CCT. O aumento ou a redução dos dias trabalhados por mês e o aumento ou a diminuição da produtividade mensal foram as outras duas variáveis que se demostraram mais sensíveis nesta formação de custo. / The aim of this study was to scale the system of cutting, loading and transportation of eucalyptus (CCT) for a forestry company located in the West of Bahia in order to process the wood to biomass burning. The system considered was the so-called "American System", which consists of the feller buncher (cut), the skidder (drag), the forestry processor (processing), forestry loader (loading and unloading) and the truck (transport). The identified equipment costs involved in this process were added up, in order to identify the standard module, which is represented by the set with the highest productivity and lowest cost, obtaining thus the largest margin of the sales value of the wood. The found results indicate that the costs of CCT, from the standard module timber processing of 40,000 m3 per month, reached between 26.6% and 34.36% of the value of the wood delivered to the end customer. The variation of percentage depends on the region where the respective customer operates. Thus, the results are average levels, suggested by the literature. Another point that underscores the importance of analyzing these operating costs, is that 65.64% - 74.40% of the selling costs of delivered wood are formed in the period of 5-7 years (which is the average growth period of a eucalyptus tree, according to the intended use of the wood), while the remaining percentage is formed in just 60 days, this period corresponds to the cutting, loading and transport of the timber to the end customer. The sensitivity analysis of the identified key variables was made. The results reveal that the way of the outbound of the wood to the end-customer and the way of coming back are the main variables to impact the percentage variation of the final CCT costs. The increase or reduction in days worked per month and the increase or decrease of the monthly yield, were the other two variables that appeared to be more sensitive in the process of cost accumulation.