BIODIVERSIDADE E SOCIODIVERSIDADE ACREANA SOB A ÓTICA CIENTÍFICA
17 de março de 2008
Tree height in Brazil's ‘arc of deforestation’: Shorter trees in south and southwest Amazonia imply lower biomass
Forest Ecology and Management Article in Press(Corrected Proof) Euler Melo Nogueiraa, Bruce Walker Nelsonb, Philip Martin Fearnsideb, , , Mabiane Batista Françaa and Átila Cristina Alves de Oliveirac aGraduate Program in Tropical Forest Science, National Institute for Research in the Amazon – INPA, Brazil bDepartment of Ecology, National Institute for Research in the Amazon – INPA, Av. André Araújo, 2936, C.P. 478, 69.011-970 Manaus, AM, Brazil cGraduate Program in Ecology, National Institute for Research in the Amazon – INPA, Brazil Received 20 August 2007; revised 30 January 2008; accepted 4 February 2008. Available online 17 March 2008.
This paper estimates the difference in stand biomass due to shorter and lighter trees in southwest (SW) and southern Amazonia (SA) compared to trees in dense forests in central Amazonia (CA). Forest biomass values used to estimate carbon emissions from deforestation throughout, Brazilian Amazonia will be affected by any differences between CA forests and those in the “arc of deforestation” where clearing activity is concentrated along the southern edge of the Amazon forest. At 12 sites (in the Brazilian states of Amazonas, Acre, Mato Grosso and Pará) 763 trees were felled and measurements were made of total height and of stem diameter. In CA dense forest, trees are taller at any given diameter than those in SW bamboo-dominated open, SW bamboo-free dense forest and SA open forests. Compared to CA, the three forest types in the arc of deforestation occur on more fertile soils, experience a longer dry season and/or are disturbed by climbing bamboos that cause frequent crown damage. Observed relationships between diameter and height were consistent with the argument that allometric scaling exponents vary in forests on different substrates or with different levels of natural disturbance. Using biomass equations based only on diameter, the reductions in stand biomass due to shorter tree height alone were 11.0, 6.2 and 3.6%, respectively, in the three forest types in the arc of deforestation. A prior study had shown these forest types to have less dense wood than CA dense forest. When tree height and wood density effects were considered jointly, total downward corrections to estimates of stand biomass were 39, 22 and 16%, respectively. Downward corrections to biomass in these forests were 76 Mg ha−1 (21.5 Mg ha−1 from the height effect alone), 65 Mg ha−1 (18.5 Mg ha−1 from height), and 45 Mg. ha−1 (10.3 Mg ha−1 from height). Hence, biomass stock and carbon emissions are overestimated when allometric relationships from dense forest are applied to SW or SA forest types. Biomass and emissions estimates in Brazil's National Communication under the United Nations Framework Convention on Climate Change require downward corrections for both wood density and tree height.
Nome: Evandro Ferreira Cidade: Rio Branco-Ac, Brazil Quem sou eu: Acreano, nascido em Rio Branco, Pesquisador do Inpa-Ac e do Parque Zoobotânico da UFAC. Mestrado em Botânica no Lehman College, New York, USA, e Ph.D. em Botânica Sistemática pela City University of New York (CUNY) & The New York Botanical Garden (NYBG).
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