- 期刊
馬來麻竹人工林之生長與生物量生產
The Growth and Biomass Production of Dendrocalamus asper Plantation
摘要
本研究旨在探討馬來麻竹自造林後16年間，林分生長及生產量隨林齡之自然變動，並由擇伐後生產特性之改變，以評估竹林生產力回復及維持之可能性。 新竹之胸徑生長、生成株數、斷面積生長量及生物量生產量，均因林齡之增加而增大。胸徑自植後第9年始即趨於穩定。生成株數於第3年屆至最大值後，即逐年降低，在自然枯死發生後，尤為明顯。斷面積及生物量之年生產量均以8年生之林分為最大，若未及時擇伐逾熟老竹，生產量將急遽降低。擇伐於植後第15年施行時，翌年新竹生產量將可迅速回復。林分胸徑將隨林齡增加而持續增大至植後第15年。林分密度於9年生時屈至最大值後，即發生自然枯死，而遽減其個體株數。林分生物量及林分斷面積自造林後逐年增大，15年生林分仍在持續增加中。年淨生產量與新竹生物量生產量之年度變動式樣相似，惟隨林齡之增加，母竹生物量增長量之比率將逐年增大，在老竹發生自然枯死後，此比值將趨減少。8年生人工林之年淨生產量可達41.4 ton/ha，為目前所知國內之森林作物中，生產力最高者。欲長期維持或改良其生產力，適時擇伐老竹以調整生育空間及竹齡結構，為一關鍵之育林作業。
並列摘要
Dendrocalamus asper, a thick-walled sympodial bamboo with high utilization potential, was first introduced to Taiwan in 1967. A 5*5 m trial plantation with 0.1 ha was established in 1972. Results of stand growth and biomass production of D. asper during the following sixteen years after planting are presented in this study. The diameter and basal area growth, biomass accumulation and net production were all substantial increased with the increasing stand ages. The maximum net annual production, which was estimated as 41.4 ton*ha^(-1), were recorded at the eighth years after planting, intensive natural-mortality due to density competition occured beyond this stage. Severe competition significantly affect the plantation productivity by reducing the number of emerging culms and increasing ratio of abortive shoots. An average of 9.3 ton*ha^(-1) of net annual biomass production was obtained for. the trial stand between the age of twelve to fifteen. The plantation regained its high productivity as 26.3 ton*ha^(-1) one year after removing the culms older than four years old. To regulate the spatial distribution and age structure by harvesting the over-matured culms properly is crucial for sustaining the high yield of D. asper. The possible effects of selective cutting on releasing the competition stress to promote the stand productivity are discussed.