Typhoon Disturbance and Forest Dynamics: Lessons from a Northwest Pacific Subtropical Forest.

Strong tropical storms are known to affect forest structure, composition, and nutrient cycles in both tropical and temperate regions, although our understanding of these effects disproportionally comes from regions experiencing much lower cyclone frequency than many forests in the Northwest Pacific. We summarized the effects of typhoons on forest dynamics at Fushan Experimental Forest (FEF) in northeastern Taiwan, which averages 0.49 major typhoons annually, and compared their resistance and resilience to those of forests in other regions. Typhoons cause remarkably few tree falls at FEF; multiple typhoons in 1994 felled only 1.4% of canopy trees, demonstrating high structural resistance. The most important effect of typhoons in this ecosystem is defoliation, which maintains high understory light levels and enhances heterogeneity, sustaining diversity without large canopy gaps. The vulnerability of taller trees to being blown down has resulted in the short-stature FEF (mean canopy height is 10.2 m). As the FEF is P-limited and a large fraction of total annual P export occurs during typhoons, these storms may have the effect of reducing productivity over time. DIN and K export only remain elevated for days at FEF, in contrast to the several years observed in Puerto Rico. High resilience is also evident in the rapid recovery of leaf area following typhoons. Heavy defoliation and slow decomposition are among the processes responsible for the high resistance and resilience of FEF to typhoon disturbance. These key structural features may emerge in other forest ecosystems if the frequency of major storms increases with climate change. [ABSTRACT FROM AUTHOR]