Professor Kai Wei Juang, Dr Chuang Wen Pai, Associate Professor Chih Hsin Cheng, Dr Chiou Pin Chen
1Department of Agronomy, National Chiayi University, Chiayi, Taiwan, 2The Experimental Forest, National Taiwan University, Nantou, Taiwan, 3School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan, 4The Experimental Forest, National Taiwan University, Nantou , Taiwam
Native vegetation has been mostly replaced by Japanese cedar in the montane area of central Taiwan since the 1950s. Soil carbon content is known to decline once natural forests replaced by the plantations. Therefore, to understand the litter decomposition rate of the adjacent natural broadleaf and the Japanese cedar (Cryptomeria japonica) forests is helpful for estimating carbon and nutrients cycling after the natural broadleaf forest replaced by Japanese. Litter bag method was used to evaluate the litter decomposition rate. Forty-two litter bags filled with 3.0 g leaf litter were placed in each study stand (three study plots for each stand) since March 2016. Six litter bags were retrieved at 7 time intervals (1, 2, 3, 6, 10, 16, 25 months) from March 2016 to April 2018. Litter samples were oven dried (60 ℃, 72 h) and the remaining mass of litter was measured, and C, N, P, K, Ca, and Mg contents of litter were also analyzed. The results indicated that the decomposition rate of the litter under natural broadleaf forest was more rapid than that under Japanese cedar forest. After over 2-year insitu incubation, the litter remaining weight was 0.40 g (12.78 %) for natural broadleaf forest and 1.1 g (35.28 %) for Japanese cedar forest. C/N ratio of both two forests decreased with the incubation time, and the litter under natural broadleaf forest displayed the lower C/N ratio than Japanese cedar at all time intervals. The higher lignin concentration of Japanese cedar pine litter, which is more biodegradation resistant, was considered to contribute to the higher remaining weight and C/N ration. Since the analysis of P, K, Ca, and Mg contents of litter haven’t finished, more results for estimating the nutrient contribution to forest soil will be presented in the future.
Dr. Chiou-Pin Chen got her PhD from the Department of Agricultural Chemistry, National Taiwan University, Taiwan. She has been working in The Experimental Forest, National Taiwan Univesity for 10 years, and current position is associate research fellow.