惠蓀實驗林場桂竹林生物量與養分聚積

Abstract

為了解久未經撫育竹林之生物量及養分聚積，選用惠蓀林場之桂竹林為例 進行調查，經選定樣區後，以層別刈取法測定樣竹之各項形質生長、解剖 構造及材積，以相對生長式估算林分生物量，並以加權平均法推算林分之 養分聚積。由林分樣區調查結果顯示，此桂竹林分密度為17,445株/公頃 ，其中一年生比例較少約佔5.1%，五年生以上 (含五年生)的樣竹較多 約36.3%，於樣區皆伐後9個月新生竹株數甚多。地下莖部分，主分佈於地 下 0-20cm處，20-40cm處較少，40cm以下者甚少或無。此外，以迴歸式推 估材積可得本林分之材積為41.26m3/ha。在生物量之推估中，樣竹胸徑與 地上部生物量具正相關，以此推估全林分地上部之生物量約為44.26公噸/ 公頃，而地下部為40.12公噸/公頃，其中地上部稈部：枝部：葉部約為 75：19：6。至於地上部養分聚積以稈部最大，而枝及葉的養分隨不同年 齡而異，地下部之養分以氮為最高，鉀次之，磷、鈉、鎂則較少。

The purpose of this study is to investigate the aboveground biomass and nutrient accumulation of unmanaged careful makino bamboo (Phyllostachys makinoi) stands in Hui-Sun Experimental forest station. Sample trees were selected from different DBH classes, using the stratified clip method, to obtain the growth parameters, dissected structure, and volume. And then use the allometric method to estimate the stand biomass. The results show that the stand density is 17,445 culms/ha. The new culms of 1-year-old is about 5.1% and the old culms of over 5-year- old (inculding 5-year-old) is about 36.3% respectively of the culms in the whole stand. The new culms produced after 9 months of clear cutting are exceeding. The biomass of underground rhizome distribute mainly in of 0- 20 cm depth, and lesser in 20-40cm layer. The distribution of rhizome beneath 40cm depth is very few. The volume of this bamboo stand is about 41.26 m3/ ha estimated by allometry method. The aboveground biomass is about 44.26 ton/ha, and underground biomass is 40.12 ton/ha. The ratio of biomass for clums : branches : leaves is 75:19:6. The nutrient accumulation of aboveground component is mostly in culms. The nutrent content in branches and leaves is changed by age. The amount of underground nutrient accumulation is largest for Nitrogen. The next is Postassium, and followed by P, Na, and Mg.