Dependence of ecosystem carbon, nitrogen and phosphorus residence times of mature forests in China on air temperature is segmented

Ecosystem mean residence times of carbon, nitrogen and phosphorus (τ e,C , τ e,N and τ e,P , respectively) are important ecosystem properties. By analyzing the dependence of the observation-based estimates of τ e,C , τ e,N and τ e,P of 127 mature forests on climate, vegetation, soil and terrain-related variables, we found that climate, particularly mean annual minimum temperature ( T min ), had the greatest influence on τ e,C , τ e,N and τ e,P . Different from previous studies, we found that both τ e,C and τ e,P increased with T min when T min > 0 ℃. Despite a decreasing phosphorus input with T min , vegetation adapted to low phosphorus environment by increasing internal recycling and phosphorus use efficiency, together with the increasing soil clay content with T min , not the direct response to T min , explained why both τ e,C and τ e,P increased with T min when T min > 0 ℃. Our results highlight the importance of factors beyond climate in regulating residence times, especially in subtropical forests.