Decomposition dynamics and driving factors of leaf litter and fine roots decomposition in secondary oak forests following different management practices in Northwestern China

Aims

The aim of the study was to evaluate how different forest management practices influence litter decomposition dynamics and nutrient release patterns, focusing on the relationship between forest management, soil conditions, and decomposition processes.

Methods

An experiment was conducted in secondary oak forests in the western Qinling Mountains of China using the litterbag decomposition methods to assess soil physicochemical properties and decomposition processes following three distinct forest management practices (details in supplementary).

Results

The results show that Structure-based Forest Management (SBFM) and Target Tree Forest Management (TTFM) significantly accelerated litter decomposition and P release, while Secondary Forest Comprehensive Silviculture (SFCS) inhibited these processes. Specifically, leaf litter decomposed at a faster rate compared to fine roots, whereas fine roots exhibited a more rapid release of N and P. The rates of decomposition were influenced by various factors including soil physicochemical properties, microbial activity, and enzyme presence. In particular, soil total phosphorus (TP) and acid phosphatase (ACP) played a critical role in promoting litter mass loss and nutrient release. Conversely, soil total nitrogen (TN) and water content significantly impacted the release of C and N, respectively.

Conclusions

SBFM and TTFM enhanced litter decomposition and nutrient cycling by improving TP and ACP activity, whereas SFCS suppressed these processes. Leaf litter tends to conserve N and P strategy, while fine roots opt for a C conservation strategy. These results highlight the critical role of forest management in regulating decomposition through soil condition modification, providing actionable insights for sustainable forestry.