Carbon Stocks of Coarse Woody Debris in Central African Tropical Forests

Abstract

Coarse Woody Debris (CWD; defined here as fallen and standing dead trees and tree branches) is a critical-structural and functional component of forest ecosystems that typically comprises a large proportion of total aboveground carbon storage. Coarse woody debris estimation for the tropics is uncommon, and little is known about how carbon storage in CWD will respond to climate change. Given the predominant role that tropical forests play in global carbon cycling, this information gap compromises efforts to forecast climate change impacts on terrestrial carbon balance. In this study, we aimed to identify the variation in Coarse Woody Debris (CWD) stocks between forest types (Old-growth and selective logging forests) and among the plots in Ipendja mixed lowland terra firme tropical rainforest (central Africa), and we examined the consequence for CWD carbon stocks estimation. The study area is located at Ipendja forest management unit (UFA), close to Dongou district (Likouala Department), in Northern Republic of Congo. Data collection were done with eight rectangular plots, each 25 x 200 m (0.5 ha). The method of line intercepts sampling has been used in each studied site. A total number of 135 CWD samples of diameter ³ 10 cm in the studied plots have been recorded. It was obvious that stock of coarse woody debris in Mokelimwaekili site (mean: 19.96 Mg ha^-1; sum: 79.84 Mg ha^-1) were higher than those of Sombo site (mean: 8.9 Mg ha^-1; sum: 35 Mg ha^-1). There was a significance difference in Ipendja evergreen forest about CWD stocks across two forest types and plots. This finding suggests that values vary among forest types and that separate reference values should be adopted for estimates of undisturbed forest carbon stocks in the different ecosystems in Congo basin. Different reference values represent the variability of CWD among forest types and contribute to reducing uncertainties in current estimates of carbon stock in central African forest ecosystems.