Fungal treatments derived from Acrophialophora yunnanensis accelerate decomposition and reduce potential flammability of forest surface litter

Background Surface litter links nutrient cycling with fuel accumulation in forests. The capacity of fungal and enzyme treatments to accelerate litter decomposition while reducing potential flammability remains insufficiently characterized. We conducted 90-day laboratory microcosm and in situ field experiments using leaf litter from three tree species. We evaluated the effects of a live strain of Acrophialophora yunnanensis and its crude enzyme preparation on decomposition, lignocellulosic degradation, and combustion-related properties. Results In the laboratory, both treatments increased mass loss and effective whole-incubation decay coefficients ( k ), promoted cellulose, hemicellulose, and lignin losses, and reduced the lignocellulose index (LCI). These responses were accompanied by lower surface litter loads and greater calorific value loss. Field-deployed litter showed similar changes in litter load and calorific value loss, with the live strain producing more consistent increases in mass loss. Responses of ignition temperature, ash content, and crude fat content varied among litter types and treatments. Cone calorimetry of field-decomposed litter showed lower peak heat release rates and total heat release under both treatments, whereas ignition time and flame duration varied. Both treatments also showed lower comprehensive flammability scores (CFS) than the control in laboratory and field settings. Random forest regression identified cellulose loss as the strongest predictor of CFS, with hemicellulose and lignin losses also contributing predictive information. Conclusions The live strain of A. yunnanensis and its crude enzyme preparation accelerated litter decomposition and reduced potential flammability under the tested conditions. These findings highlight the potential of fungal and enzyme preparations for surface-fuel management through enhanced litter decomposition. Further independently replicated field trials using undried litter are needed to establish their performance under natural conditions.