阿里山石棹地區石竹林分結構及生物量

The stand structure and biomass accumulation of Phyllostachys lithophila in Shi-Zhuo, Alishan

石竹係臺灣重要經濟竹種之一，主要以生產竹筍為主，石竹筍係嘉義阿里山地區之重要特產。本研究調查阿里山石棹地區石竹林分結構、林分生長性狀以及生物量乾重累積狀況。研究結果顯示，阿里山石棹地區石竹林分密度為10,567±1,553株ha-1，其中以4年生及以上所佔比率 51.42%最高，2年生所佔比率14.51%最低；林分生長性狀，石竹竹稈平均胸徑為7.3±1.3 cm，平均竹高為14.9±1.9 m，平均枝下高為7.7±1.6 m；石竹生物量乾重累積狀況，地上部生物量乾重為 124.4±27.8 ton ha-1，地下部生物量乾重為54.0 ton ha-1，地下部與地上部比值為0.43。進一步分析各齡級地上部生物量乾重發現4年生及以上為72.0±16.0 ton ha-1 （57.9%），3年生為38.6±17.8 ton ha-1 （31.1%），2年生則僅有13.8±3.9 ton ha-1 （11.1%），顯示石棹石竹林老齡竹過多，新生竹過少，應積極進行老竹伐採等經營管理，以提高新生竹生產力。 Thill bamboo (Phyllostachys lithophila), primarily used for bamboo shoot, is one of the economic bamboo species in Taiwan. Thill bamboo shoot is one of the most important local products in Alishan Area. This study investigated the stand structure, stand growth and biomass of P. lithophila in ShiZhuo, Alishan. Results showed that, the average of stand density was 10,567±1,553 culms ha-1. Among frequency distribution in age structure, the highest one was found for those above 4-year-old at 51.42%, and the lowest one is those on 2-year-old at 14.51%. The average DBH was 7.3±1.3 cm, average height of bamboo was 14.9±1.9 m, and the average height under branches was 7.7±1.6 m. The aboveground biomass was 124.4±27.8 ton ha-1, and the belowground biomass was 54.0 ton ha-1. Furthermore, the aboveground biomass was 72.0±16.0 ton ha-1 on above age 4, 38.6±17.8 ton ha-1 on 3 year-old, and only 13.8±3.9 ton ha-1 on 2 year-old. This result indicated that the age distribution of P. lithophila stand was unbalanced, therefore, the old culms should be cut down to increase the productivity of P. lithophila plantation.