# Intrinsic nutrients and defensive compounds drive coarse woody debris decay in five dominant subtropical tree species, China

## TL;DR

This study shows how different tree species in subtropical forests decompose at different rates, influenced by nutrients and chemical defenses in their wood.

## Contribution

The study identifies how intrinsic wood traits, like nutrients and defensive compounds, drive decomposition rates in subtropical CWD.

## Key findings

- Broadleaved species decomposed fastest, while conifers decomposed slowest.
- Phosphorus was rapidly released in the first year, while nitrogen accumulated over time.
- Defensive compounds like tannins had a weak effect on early-stage decay.

## Abstract

Coarse woody debris (CWD) is crucial for carbon and nutrient cycling in forest ecosystems, with decomposition rates influenced by species-specific wood traits. This five-year study in a subtropical Chinese forest evaluated the CWD decomposition of five dominant species. Results showed that broadleaved species decomposed fastest (k = 0.230 years−1), followed by moso bamboo (0.168 years−1), and conifers slowest (0.022 years−1). Fast-decaying species were characterized by high hemicellulose, cellulose, and phosphorus (P) content, with rapid P release within the first decay year and nitrogen (N) accumulation over time. Tannin initially inhibited decay in fast-decaying species, but defensive compounds (tannins and phenolics) showed no sustained effect on decomposition rates. These findings indicate active CWD decomposition in subtropical forests, where P limitation outweighs N for broadleaves and bamboo. Defensive compounds only weakly influenced early-stage decay. Our results enhance the understanding of deadwood decomposition and carbon sink dynamics in subtropical ecosystems.

•Studied the differences in wood decomposition rates among dominant subtropical forest species•Nitrogen and phosphorus regulate coniferous species decay during early decomposition stages•Phosphorus is rapidly released in the first year while nitrogen accumulates over time•Defensive tannins and phenolics have a weak effect to inhibit decay at early stage

Studied the differences in wood decomposition rates among dominant subtropical forest species

Nitrogen and phosphorus regulate coniferous species decay during early decomposition stages

Phosphorus is rapidly released in the first year while nitrogen accumulates over time

Defensive tannins and phenolics have a weak effect to inhibit decay at early stage

Soil science; Plant biochemistry; Soil chemistry; Soil ecology; Soil biology