| Summary: | 碩士 === 國立中興大學 === 森林學系所 === 98 === The purposes of this study were to evaluate the internal nutrient cycling of litterfall at different elevation (temperature and rainfall) sites. Litterfall was collected monthly by traps and litter was collected trimonthly in three natural hardwood, Mt. Peitungyen (2,078 m), Hui-Sun experiment forest (1,066 m) and Lienhauchi (782 m) in central Taiwan. Monitoring litterfall amounts, nutrient flux, litter amounts and nutrient accumulation of the three sites from March 2009 to February 2010. Annual litterfall mass and decomposition constant increasing (6,583.2 to 9,180.6 kg ha-1yr-1 and 0.49 to 0.87, respectively) with decreased elevation (increasing temperature). The amount of reproduction was higher (1,031.7 kg ha-1 yr-1) in Mt. Peitungyen than in Hui-Sun experiment forest (788.2 kg ha-1 yr-1) and Lienhauchi (533.0 kg ha-1 yr-1). Nitrogen and potassium concentrations of branch and leaf were the highest in Lienhauchi. The nutrient input by litterfall increased with decreasing elevation. Using the minimum nitrogen and phosphorous concentrations in the fall leaf as the retranslocation thresholds, indicating nitrogen retranslocation was incomplete in the three sites, but phosphorous retranslocation was complete. These results suggested that phosphorous was the limiting nutrient in the three sites. Calcium, potassium, magnesium input to the forest via litterfall corresponds to the exchangeable stock in the top 60 cm soil were the highest in Hui-Sun (14.33%) and the lowest in Mt. Peitungyen (6.23%).
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