Decay rate of Larix gmelinii coarse woody debris on burned patches in the Greater Khingan Mountains

Shubo Huang,Fangbing Yu,Shuai Yin,Meng Guo,Lixiang Wen

doi:10.1007/s11676-020-01270-z

Abstract

The decomposition of coarse woody debris (CWD) affects the energy flow and nutrient cycling in forest ecosystems. Previous studies on CWD have focused on the input, decomposition, reserve dynamics, and CWD functions, but coarse woody debris decomposition is complex and the results from different regions vary considerably. It is not clear which factors affect decay rate (k), especially at different decomposition stages. In this study, a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains. The results show that the decay rate of coarse woody debris was positively correlated to decay class. The average decomposition rate was 0.019, and 41 years and 176 years are needed for a 50% and 95% mass loss, respectively. CWD nutrient content, density, and water content could explain the variance in the decay rate (~ 42%) of the decay factors such as amount of leaching, degree of fragmentation, respiration of the debris, and biotransformation, and varied significantly between different decay classes. Using the space–time substitution method, this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process. It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents. This paper quantifies the indicators affecting CWD decay to explain the decomposition process.

Highlights

Coarse woody debris (CWD) in the form of snags, downed boles or large branches is an important structural and functional component of forest ecosystems (Harmon et al 1986)
Research has combined the characteristics of coarse woody debris with forest succession (Carmona et al 2002), community composition (Motta et al 2006), nutrient cycles (Currie and Nadelhoffer 2002), and forest management (Montes and Cañellas 2006) to study its function and decomposition in forest ecosystems
Coarse woody debris accounts for approximately 5% of carbon (C) storage in terrestrial ecosystems, and in forest ecosystems, for 2–10% of

Summary

Introduction

Coarse woody debris (CWD) in the form of snags, downed boles or large branches is an important structural and functional component of forest ecosystems (Harmon et al 1986). CWD affects biotic and abiotic processes through physical and biological effects and plays an important role in longterm nutrient storage and tree regeneration (Wu et al 2005). It provides habitats for various organisms and maintains environmental heterogeneity, biodiversity, and the integrity of ecosystems. Habitat provision and nutrient storage are significant for maintaining the continuity of biodiversity and biogeochemical processes (Sturtevant et al 1997). Coarse woody debris accounts for approximately 5% of carbon (C) storage in terrestrial ecosystems, and in forest ecosystems, for 2–10% of

Methods

Results

Conclusion