蓮華池巨竹林之林分結構與地上部生物量

Growth and Aboveground Biomass of Giant Bamboo (Dendrocalamus giganteus) in Lien-Hua-Chih Area

本研究選擇林業試驗所蓮華池研究中心之巨竹林進行調查及統計分析。調查結果顯示， 2012及2013年巨竹林之齡級分布皆以4年生以上之老齡竹稈最多。直徑分布方面，2012及2013年均以直徑階14 cm < DBH ≦ 16 cm之株數最多。林分調查方面，竹叢面積平均為4.5 m2 clump-1，竹叢數平均為400 clumps ha-1，竹叢與林地面積之比例為17.8 %，2012及2013年之竹稈密度分別為4,433、 4,867 culms ha-1，2013年之枯死率平均為8.6 %。竹林生長性狀方面，2012年巨竹林之胸高直徑為 14.3 cm、稈高為17.5 m、枝下高為7.2 m；而2013年胸高直徑為14.4 cm、稈高為17.7 m、枝下高為 8.2 m，兩年度之差距不大。地上部生物量方面，2012年巨竹林之竹稈乾重為129.0 ton ha-1、竹枝乾重為17.6 ton ha-1、竹葉乾重為8.5 ton ha-1，地上部總乾重為155.1 ton ha-1；2013年巨竹林之竹稈乾重為129.8 ton ha-1、竹枝乾重為16.7 ton ha-1、竹葉乾重為7.7 ton ha-1，地上部總乾重為155.8 ton ha-1。新生竹方面，竹林分平均密度為433.3 culms ha-1，胸徑平均15.4 cm、稈高平均19.6 m、枝下高平均19 m，而新生竹比例平均9.8 %。新生竹地上部生物量方面，竹稈乾重平均12.9 ton ha-1、竹枝乾重平均 1.6 ton ha-1、竹葉乾重平均0.7 ton ha-1、地上部總乾重平均15.4 ton ha-1 （10.9~20.9 ton ha-1）。本研究蓮華池巨竹林之林分結構不良，呈現老齡竹過多與新生竹過少之失衡現象，亟待積極進行伐除老竹等之經營管理對策，藉著現存林分生物量之年增長量的提高，以達成巨竹林生長對大氣中CO2的減量效果。 This paper reports the stand structure and biomass on giant bamboo forest in Lien-Hua-Chih Area at the period of 2012 and 2013. The results resulted showed that the bamboo forest was dominated by culms with age over 4 years at both 2012 and 2013, and the culms at DBH between 14 and 16 cm were most abundant in diameter distribution. The average of clump size was 4.5 m2 clump-1, and 400 clumps ha-1 was in average which covers 17.8 % of total bamboo land. The culms density was 4,433, 4,867 culms ha-1 at 2012 and 2013, respectively. At 2012, the average of DBH, total height and the height to crown base was14.3 cm, 17.5 m and 7.2 m, respectively, and 14.3 cm, 17.5 m and 7.2 m at 2013. In the biomass above ground, at 2012, the total biomass was 155.1 ton ha-1 with the components that culms biomass was 129.0 ton ha-1, branch biomass 17.6 ton ha-1, and leaf biomass 8.5 ton ha-1. The same figures at 2012 was 155.8 ton ha-1 in total biomass, 129.8 ton ha-1 in culms biomass, 16.7 ton ha-1 in branch biomass and 7.7 ton ha-1 in leaf biomass. In regard to new culms, the average of new culms was 433.3 culms ha-1 with the average of DBH 15.4 cm, average of total height 19.6 m, the average of height to crown base 19.0 m. The average ratio of new culms was about 9.8 %. Finally, the total biomass above ground for new culms was 10.9 ~ 20.9 ton ha-1, with the components that culms biomass was 12.9 ton ha-1, branch biomass 1.6 ton ha-1, and leaf biomass 0.7 ton ha-1. Moreover, the unbalanced age distribution of culms indicated that the activity of cutting old culms should be carried out to increase the productivity of giant bamboo forest.