The immediate effect of typhoon disturbance on soil carbon fractions along a subtropical forest gap gradient

Abstract

Tropical cyclones (typhoons/hurricanes) not only destroy forest structures and shape forest gaps, but also lead to the dry soil getting wet with heavy rainfall, with an immediate effect on forest carbon (C) turnover. Yet, the short-term response of distinct forest gaps to typhoon disturbance and their influence on soil C fractions remain unknown. Taking advantage of the typhoon Doksuri, this experiment identified three key periods (i.e., pre-typhoon, typhoon, and post-typhoon) among five forest gaps (i.e., close canopy, gap edge, small gap, middle gap and big gap) to determine the immediate effect of typhoon disturbance on soil C fractions dynamics. Typhoon disturbance significantly decreased the labile soil C fractions, primarily consisting of total dissolved C in the topsoil and subsoil by 67% and 65% respectively, and slight effect on dissolved inorganic C and active organic C. Typhoon disturbance led to a decrease in recalcitrant organic C of the subsoil among different forest gaps to a certain extent, especially in the big gap. Forest soil moisture and litter nutrient storage after typhoon jointly mediated the variations in labile and recalcitrant C. These results indicate that the immediate effect of typhoon disturbance may decrease soil C fractions, with the extent of changes in distinct soil C fractions was also regulated by forest gaps. This finding emphasizes the an optimized canopy management strategy need to consider the specific responses of different forest structures to typhoons, which is essential for accurately assessing the soil C pool in cyclone-prone forests under climate change scenarios.