The degradation of lignin and cellulose in typhoon-induced unsenescent leaf litter depends greatly on functional strategies among tree species

Aims

Although unsenescent leaf litter induced by tropical cyclones represents an increasingly important component of forest litter, characterized by distinct initial quality and decomposition environments compared to naturally senescent litter, the degradation of lignin and cellulose in unsenecent litter and the underlying mechanism remain unknown.

Methods

To evaluate the effect of litter sources and tree species on lignin and cellulose degradation, we conducted a one-year litter decomposition experiment using unsenescent leaf litter induced by Typhoon Hagupit from goldenrain, camphor, and willow trees, along with naturally senescent leaf litter from each species, at the Plant Ecology Research Base of Taizhou University in southeastern China.

Results

Lignin in unsenescent camphor and willow litter degraded by 43.2% and 48.6%, respectively, which were significantly higher than in senescent litter. Cellulose in unsenescent willow litter degraded by 85.38%, also significantly higher than in senescent litter. However, cellulose in unsenescent goldenrain and camphor litter degraded by 71.4% and 73.3%, respectively, which were significantly lower than in senescent litter. Initial litter quality effectively explained the differences in lignin and cellulose degradation rates between senescent and unsenescent litter. Furthermore, lignin degradation rates in both senescent and unsenescent litter were significantly and positively correlated with carbon (C) release, while cellulose degradation rates had a positive correlation with C release only in senescent camphor litter.

Conclusions

The degradation of lignin and cellulose in typhoon-induced unsenescent litter varies greatly among tree species due to their distinct functional strategies, highlighting its disproportionate contribution to C cycle in coastal forest ecosystems.