Litterfall is a fundamental and important part in nutrient cycling. It can be transfer to organic matter and mineral elements via decomposition and it affected by both seasonal and long term climate variability. In southeast of Taiwan, The Lanjenchi plot is a spatially heterogeneous forest which the typhoons and northeast monsoon in summer and winter respectively have strong impact on here. These two climate factors make the forest divided into different habitats. In order to understand what the difference between litterfall composition in these different habitats, we collected the short-term data from 2012-2014 and long-term metatdata from the different researches during 1991-2013. The litterfall was oven dried monthly during 2012-2014 and the metadata was analyzed with climate data to find out the truly impact factors on annual litterfall change.
The results from short-term collected data showed that the annual litterfall was 7.84 t ha-1 yr-1 and reaching the peak during the typhoon season in summer. It had higher annual litterfall when stronger typhoon hit the plot, but the amount of annual litterfall drop into low point for several years until the next stronger typhoon coming. Annual temperature, total precipitation and maximum wind speed were the factors that affect the annual litterfall pattern, and especially the maximum wind speed was the most significant factor. Our results suggested that the strength of typhoon is the main factor which causing the different annual pattern in Lanjenchi forest. The forest will recover the canopy after the strong typhoon disturbance so that the litterfall will less than before. Numerous research have already pointed out the strength and the number of typhoon was increasing under the global warming. On the contrary, the speed of northeast monsoon was getting decrease in recent years. If the frequency of typhoon disturbance keeping increasing, the nutrient cycling and the tree growth in Lanjenchi forest may be affected seriously in the future.