Carbon and nitrogen stocks in dead wood of tropical lowland forests as dependent on wood decay stages and land-use intensity

Selis Meriem,Triadiati Triadiati,Soekisman Tjitrosoedirjo,Dietrich Hertel,Martyna Malgorzata Kotowska

doi:10.15287/afr.2016.524

Selis Meriem, Triadiati Triadiati + Show 3 more

Open Access

https://doi.org/10.15287/afr.2016.524

Copy DOI

Abstract

Rapid transformation of natural forests into other land-use systems in the lowlands of Sumatra, Indonesia, strongly reduces total aboveground biomass and affects nutrient cycling. However, the consequences of this conversion for C and N stocks of dead wood remains poorly understood particularly in natural forests and jungle rubber. This study examined the differences in dead wood abundance, and C, N and lignin concentrations of three decay stages of dead wood as well as the stocks of these chemical components stored in dead wood. Standing and fallen dead wood was determined as coarse woody debris with diameter ≥ 10 cm and classified into three decay stages of wood. Mass of dead wood was estimated using allometric equation. Total C and N stocks in dead wood in the natural forests (4.5 t C ha -1 , 0.05 t N ha -1 , respectively) were three times higher than those in the jungle rubber (1.5 t C ha -1 , 0.02 t N ha -1 , respectively). The stocks of C and N at early and advanced wood decay stages in the natural forests were also higher than those in the jungle rubber. The decay stages showed pronounced differences in concentrations of chemical components. With advancing stage of wood decay, N concentration increased and C/N ratio decreased, while concentrations of C and lignin were variable. The distribution of dead wood mass and stocks of C, and lignin were found to be higher in the early decay than those in the advanced decay stage. Higher input of dead wood in natural forests indicated a higher importance of dead wood decay in natural forests than in jungle rubber systems. Thus, replacing natural forests with jungle rubber strongly reduces total C and N stocks which might have a marked negative effect on the ecosystems' nutrient turnover and cyle.

Highlights

Dead wood has been recognized to have an important ecological function as a resource for the ecosystem and structural components of forests (Harmon et al 1986)
The higher mass of dead wood in the natural forest subsequently led to a highly significant differences in stocks of lignin, C, and N compared to the jungle rubber (p < 0.05) (Fig. 1 C-E)
Each decay stage of dead wood had different volume, mass, and stocks of lignin, C, and N that differed as well as between natural forest and jungle rubber (Table 2). These parameters were significantly higher for decay stage I in the natural forest compared to the jungle rubber (p < 0.05) as well as for decay stage III (p < 0.05), while there was no significant difference between the two systems for decay stage II (p > 0.05) (Table 2)

Summary

Introduction

Dead wood has been recognized to have an important ecological function as a resource for the ecosystem and structural components of forests (Harmon et al 1986). Enhancing dead wood amounts is expected to increase the habitat for forest biota. Dead wood contributes a significant proportion to the total C stocks of aboveground wood mass (Pfeifer et al 2015). This input serves as an important source to the nutrient flux to soil and consequentially affects the forest nutrient cycle. Dead wood stores C retention as a fraction of total above-ground carbon pool, and contributes to soil C sequestration (Pan et al 2011)

Objectives

Methods

Results

Conclusion