Brazil carbon budget for 1990s Export

@article{404, abstract = {A major reason for alarm over the rate and magnitude of deforestation in Brazil has been concern that the reduction in vegetation releases carbon dioxide (CO2) and other greenhouse gases (GHG) that may contribute to global climate change. While deforestation releases CO2\_and other GHG, however, tree growth elsewhere absorbs atmospheric carbon (C) through photosynthesis. discussions of CO2\_releases from tropical deforestation have tended to focus on gross releases and have generally not considered the effects of carbon uptake. The objective of this paper is to examine the net C balance for Brazil, by estimating both CO2\_- C release and uptake. Our approach was to construct a generalized conceptual model of ecosystem C cycling that could be applied to any vegetation type and can be quantified with available data. the primary C pools in the model are the atmosphere, live vegetation, litter and coarse woody debris, and soil. Fluxes are represented as transfer between these pools that occur as a result of land use change, disturbance or recovery from past disturbance by plant growth and accumulation of organic matter. To estimate ecosystem areas, we used and adapted the most recently completed and current vegetation map available (Stone et al. in press). The primary sources for C density data were a report compiled by Olson et al (1983) and a subsequent version. We also used an alternative C density for closed moist forest from Brown and Lugo (1992). These forests play a major role in Brazil's C balance, but there is some uncertainty regarding their C density. We attempted to bracket this uncertainty by using both high and low values. We also used published data to calculate flux estimates. A major flux in Brazil's C budget is release to the atmphere resulting from deforestation. In 1990, 1.38 x 10(6) ha of closed forest were cleared in Brazil. Additionally, about 1.0 x 10(6) ha of cerrado woodland also cleared. We also estimated that 0.35 x 10(6) ha of secondary forest were cleared that year. Total C releases for the country as a whole were 174 - 233 x 10(6) tc/yr. The difference was caused mostly by differing estimates in the C density of closed tropical moist forests, which resulted in different fluxes from deforestation and burning. Net changes in pool sizes of our C budget model varied. The total vegetation C pool decreased by 160 - 240 x 10(6) tc/yr. The soil pool also lost C, about 80 x 10(6) tc/yr as a result of disturbance from forest clearing and intensive agriculture. However, the litter/coarse woody debris pool increased by 70 - 90 x 10(6) tc/yr. This increase was due to transfers from the vegetation pool due to clearing of closed tropical moist forest. Total gross C uptake by the system was 100 x 10(6) tc/yr of which 60 x 10(6) was addition to litter and soil pools in secondary forets. Total C releases were 120 - 150 x 10(6) tC/yr from deforestatio/burning and 150 - 180 x 10(6) tC/yr from decomposition. Most of the C released from burning was derived from above-ground vegetation but a significant amount also came form litter and coarse woody debris, including from reburning of residual logs and pastures}, author = {Schroeder, P. and Winjum, J. K.}, citeulike-article-id = {1309813}, journal = {Interciencia}, keywords = {accumulation, agriculture, amazonia, atmosphere, atmospheric\_carbon, balance, biomass, brazil, carbon, carbon\_balance, carbon\_budget, climate, climate\_change, co2, conceptual\_model, decomposition, deforestation, disturbance, dynamics, ecosystem, fif, forest, growth, land\_use, land\_use\_change, litter, matter, model, moist\_forest, organic\_matter, pasture, photosynthesis, plants, release, sinks, slash, soil, soils, tree\_growth, trees, tropical, tropical\_deforestation, tropical\_forests, tropical\_moist\_forest, uncertainty, vegetation}, pages = {68--75}, posted-at = {2007-05-19 23:34:39}, priority = {2}, title = {Brazil carbon budget for 1990s}, volume = {20}, year = {1995} }

TY - JOUR ID - 404 L3 - citeulike-article-id:1309813 N2 - A major reason for alarm over the rate and magnitude of deforestation in Brazil has been concern that the reduction in vegetation releases carbon dioxide (CO2) and other greenhouse gases (GHG) that may contribute to global climate change. While deforestation releases CO2_and other GHG, however, tree growth elsewhere absorbs atmospheric carbon (C) through photosynthesis. discussions of CO2_releases from tropical deforestation have tended to focus on gross releases and have generally not considered the effects of carbon uptake. The objective of this paper is to examine the net C balance for Brazil, by estimating both CO2_- C release and uptake. Our approach was to construct a generalized conceptual model of ecosystem C cycling that could be applied to any vegetation type and can be quantified with available data. the primary C pools in the model are the atmosphere, live vegetation, litter and coarse woody debris, and soil. Fluxes are represented as transfer between these pools that occur as a result of land use change, disturbance or recovery from past disturbance by plant growth and accumulation of organic matter. To estimate ecosystem areas, we used and adapted the most recently completed and current vegetation map available (Stone et al. in press). The primary sources for C density data were a report compiled by Olson et al (1983) and a subsequent version. We also used an alternative C density for closed moist forest from Brown and Lugo (1992). These forests play a major role in Brazil's C balance, but there is some uncertainty regarding their C density. We attempted to bracket this uncertainty by using both high and low values. We also used published data to calculate flux estimates. A major flux in Brazil's C budget is release to the atmphere resulting from deforestation. In 1990, 1.38 x 10(6) ha of closed forest were cleared in Brazil. Additionally, about 1.0 x 10(6) ha of cerrado woodland also cleared. We also estimated that 0.35 x 10(6) ha of secondary forest were cleared that year. Total C releases for the country as a whole were 174 - 233 x 10(6) tc/yr. The difference was caused mostly by differing estimates in the C density of closed tropical moist forests, which resulted in different fluxes from deforestation and burning. Net changes in pool sizes of our C budget model varied. The total vegetation C pool decreased by 160 - 240 x 10(6) tc/yr. The soil pool also lost C, about 80 x 10(6) tc/yr as a result of disturbance from forest clearing and intensive agriculture. However, the litter/coarse woody debris pool increased by 70 - 90 x 10(6) tc/yr. This increase was due to transfers from the vegetation pool due to clearing of closed tropical moist forest. Total gross C uptake by the system was 100 x 10(6) tc/yr of which 60 x 10(6) was addition to litter and soil pools in secondary forets. Total C releases were 120 - 150 x 10(6) tC/yr from deforestatio/burning and 150 - 180 x 10(6) tC/yr from decomposition. Most of the C released from burning was derived from above-ground vegetation but a significant amount also came form litter and coarse woody debris, including from reburning of residual logs and pastures JF - Interciencia EP - 75 TI - Brazil carbon budget for 1990s VL - 20 SP - 68 KW - accumulation KW - agriculture KW - amazonia KW - atmosphere KW - atmospheric_carbon KW - balance KW - biomass KW - brazil KW - carbon KW - carbon_balance KW - carbon_budget KW - climate KW - climate_change KW - co2 KW - conceptual_model KW - decomposition KW - deforestation KW - disturbance KW - dynamics KW - ecosystem KW - fif KW - forest KW - growth KW - land_use KW - land_use_change KW - litter KW - matter KW - model KW - moist_forest KW - organic_matter KW - pasture KW - photosynthesis KW - plants KW - release KW - sinks KW - slash KW - soil KW - soils KW - tree_growth KW - trees KW - tropical KW - tropical_deforestation KW - tropical_forests KW - tropical_moist_forest KW - uncertainty KW - vegetation AU - Schroeder, P AU - Winjum, JK PY - 1995/// ER -