Tree allometry and improved estimation of carbon stocks and balance in tropical forests

Abstract

Tropical forests hold large stores of carbon, yet uncertainty remains regarding their quantitative contribution to the global carbon cycle. One approach to quantifying carbon biomass stores consists in inferring changes from long-term forest inventory plots. Regression models are used to convert inventory data into an estimate of aboveground biomass (AGB). We provide a critical reassessment of the quality and the robustness of these models across tropical forest types, using a large dataset of 2,410 trees >or= 5 cm diameter, directly harvested in 27 study sites across the tropics. Proportional relationships between aboveground biomass and the product of wood density, trunk cross-sectional area, and total height are constructed. We also develop a regression model involving wood density and stem diameter only. Our models were tested for secondary and old-growth forests, for dry, moist and wet forests, for lowland and montane forests, and for mangrove forests. The most important predictors of AGB of a tree were, in decreasing order of importance, its trunk diameter, wood specific gravity, total height, and forest type (dry, moist, or wet). Overestimates prevailed, giving a bias of 0.5-6.5% when errors were averaged across all stands. Our regression models can be used reliably to predict aboveground tree biomass across a broad range of tropical forests. Because they are based on an unprecedented dataset, these models should improve the quality of tropical biomass estimates, and bring consensus about the contribution of the tropical forest biome and tropical deforestation to the global carbon cycle.

Tree Diversity Changes over a Decade (2003-2013) in Four Inland Tropical Dry Evergreen Forest Sites on the Coromandel Coast of India

“…For multi-stemmed trees, bole girths were measured separately. The recensus (2013) results were compared with initial inventories (2003) to analyse the changes in tree density over a decade (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) at species and stand levels and for aboveground biomass -ABG (Chave et al 2005). For species diversity and evenness, the Shannon (H') Simpson () and Fisher's (α) diversity indices were calculated (Magurran 2004).…”

Assessment of Aboveground Woody Biomass Dynamics Using Terrestrial Laser Scanner and L-Band ALOS PALSAR Data in South African Savanna

“…However, the associated errors, mainly emanating from sampling procedures and errors associated with the allometric models, need to be taken into consideration. Until 2005, most allometries considered only the relationship between biomass, plant diameter, and wood specific density [5,6,8], leaving out the height variable. Examples of such allometries are presented in [6] where a linear relationship between AGB and log-transformed trees with D >33 cm in Kruger National Park (KNP) was derived, with 16% and 12% errors for woody and leaf biomass, respectively.…”

“…Allometric models are developed based on relationships between biomass and tree characteristics such as height and basal diameter [7]. Such relationships are therefore prone to errors associated with models used in their development [5,8]. Forest impenetrability, and time and financial constraints, have led to localized field inventories with few tree species [9], which are not representative over large areas [3,10].…”

Homegardens as a Multi-functional Land-Use Strategy in Sri Lanka with Focus on Carbon Sequestration

“…1) developed by Brown et al (1989) for wet zone homegardens encompassing the variables DBH, height and wood density and the allometric equation (Eq. 2) developed by Chave et al (2005) for dry zone homegardens including the same variables were used in this categorization. These two allometric equations can be expressed as follows:…”