Allometric equations for total, above- and below-ground biomass and carbon of the Amazonian forest type known as campinarana

ABSTRACT The Amazon forest comprises many different forest types, amongst them are campinas and campinaranas, which occur on Amazonian sandy soils, representing 2.65% of Amazonian territory. An understanding of the ecology and quantification of the environmental goods and services of campinaranas is key to their conservation. Based on a direct method to estimate biomass and carbon content of campinarana, we harvested and weighted 89 trees and other forest components in ten randomly allocated plots of 100 m2 (10 x 10 m) and 11 additional trees outside the plots. The data allowed us to describe how biomass is distributed amongst campinarana vegetation and amongst tree compartments. We developed allometric equations to estimate the total, above- and below-ground biomass and carbon stock of this forest type. We used a Weibull function to test if the diameter distribution of the individual trees sampled was consistent with the diameter distribution of the forest type. We also tested if terra-firme forest biomass equations could be used to estimate campinarana biomass, and whether a correction factor based on dominant height would reduce the error from these estimates. Allometric equations are considered to be the most reliable and rapid method for calculating forest biomass, and are used in forest management and climate change studies. These are the first total biomass equations developed for central Amazonian campinaranas. The best fitted allometric equation for total fresh biomass was: ln (Total Biomass) = -1.373 + 2.546 * ln DBH (R ² = 0.98, Sxy% = 4.19%).