Densidade da madeira de árvores em savanas do norte da Amazônia brasileira

Abstract

Densidade da madeira (DM) é uma variável importante para estimativas de estoques de carbono arbóreo em ecossistemas terrestres. Este tema é pobremente investigado em áreas de savana da Amazônia brasileira. O objetivo deste estudo foi investigar a DM das oito principais espécies arbóreas que ocorrem na savana aberta de Roraima, a maior área de savana do norte do bioma Amazônia. Foram verificadas as variações na DM em função da espécie e dos diferentes diâmetros observados ao longo da dimensão vertical de 75 indivíduos amostrados em seis sítios de coleta. Foi utilizado o método direto para obtenção de peças de madeira do fuste e da copa. Os resultados indicaram discrepância significativa interespecífica, sendo Roupala montana Aubl. a espécie de maior DM média (0,674 g cm -3 ). Foi detectado que existe variação significativa da DM entre as peças do fuste e da copa, independente da espécie e do sítio de coleta. A densidade da madeira de peças da copa com diâmetro entre 5 e 10 cm pode ser utilizada como preditora da DM média do indivíduo arbóreo. Nós concluimos que a DM das oito espécies arbóreas investigadas possui variabilidade interespecífica, com discrepâncias entre a DM do fuste e das partes lenhosas da copa. As distinções aqui detectadas devem ser considerados como uma importante ferramenta para melhorar as estimativas de estoque de carbono em áreas de savanas na Amazônia. PALAVRAS-CHAVE: biomassa, carbono, cerrado, lavrado, Roraima. Wood density of trees in savannas of the northern Brazilian Amazon ABSTRACTWood density (WD) is an important variable for estimating tree carbon stocks in terrestrial ecosystems. WD has been little studied in savanna areas in the Brazilian Amazon. The aim of this study was to investigate variation in WD in eight tree species that occur in the open savannas of Roraima, the largest savanna area in the northern Brazilian Amazon. Variations were observed in WD in relation to species and diameter along the vertical dimension of 75 individuals sampled at six study sites. We used the direct method to obtain wood pieces from the stem and crown. The results indicated significant interspecific differences. Roupala montana Aubl. was the species with highest WD (0.674 g cm -3 ). Significant variation in WD was found between the stem and the woody parts of the crown, irrespective of species or sampling site. The wood density of branchs with diameter between 5 and 10 cm can be used as a predictor of individual WD for the whole tree. We conclude that the WD of the eight tree species investigated has interspecific variability and that there is a discrepancy between the WD of stem and the woody parts of the crown. Distinctions detected here provide an important tool for improving tree carbon estimates in Amazonian savannas.

Spatial and Temporal Variations in Aboveground Woody Carbon Storage for Cerrado Forests and Woodlands of Mato Grosso, Brazil

“…Oven drying at temperatures <100 ° C may lead to errors in the measurement of wood density because bound water in wood cannot be completely driven off at lower temperatures (Williamson & Wiemann, ). While the magnitude of this potential error for our data is unknown, our mean (+ SD ) wood density for the cerrado tree Curatella americana (0.62 + 0.07 g/cm 3 ; n = 45 trees) was similar (0.67 g/cm 3 ; n = 18 trees) to that reported by Jati et al (), who dried their cores at >100 ° C. Trunk ρ was calculated as the dry mass of wood divided by the volume of the fresh wood core (Chave et al, ). Wood C concentration was measured from the dried cores using a wet combustion (Walkley‐Black) method (Vourlitis et al, ).…”

Influence of Interspecific Variation on Tree Carbon Stock of a Brazilian Cerrado

“…The wood density of the unharvested species was obtained in literature (Vale et al, 2002;Paula and Alves, 2007;Lorenzi, 2009;Zanne et al, 2009;Jati et al, 2014) and an average carbon content was calculated to estimate carbon stock using the mean values found for sampled species.…”

Estimation of the Basic Wood Density of Native Species Using Mixed Linear Models

“…Further, depending on the utilization of this factor, one can estimate the forest biomass and carbon stock (Baccini et al, 2012;Saatchi et al, 2011). Thus, knowledge about this basic wood density (DB) of native species aids in the conservation and sustainable exploitation of forests (Chave et al, 2005(Chave et al, , 2014Jati et al, 2014;Djomo et al, 2016).…”