苗栗海岸砂丘木麻黃人工林之生長及林分生物量

The Growth and Stand Biomass of Casuarina Plantation at Miao-Li Coastal Sand-dune

陳財輝(Tsair-Fuei Chen) ； 呂錦明(Chin-Ming Lü)

《林業試驗所研究報告季刊》 3卷1期 (1988/03) Pp. 333-343

https://doi.org/10.7075/BTFRI.198803.0333

摘要

對栽植於苗栗縣後龍海濱砂丘之8年生木麻黃人工林實施樣區調查，以分層平均木法選取樣木，並以層別刈取法測定樣木各項生長形質，再以相對生長關係式估算林分生物量，由林分調查結果顯示，木麻黃樣區林分密度皆超過每公頃5,000株，林分均呈現過密狀態，且其林分大部分皆由細長的個體所組成。木麻黃樣木之生產構造中，葉量及枝量之垂直分布大部分在地面高3.3~6.3m 之間，幹、枝、葉、根量大致呈隨林木個體的增大而增加之現象。樣木之林冠投影面積在0.580~4.740平方公尺之間，由於本試驗地冬期之東北季風強烈，林木皆呈偏冠生長，再加上林分密度過高，林木間相互凌壓的現象極為嚴重。樣木根系之分布主要在地表下 0~120口之間，其分布面積在0.784~5.096平方公分之間，亦呈隨個體之增大而增加，樹體由於長年受到風力之吹襲，導致林木根系之生長方向與樹冠生長方向相反。樣木各生長形質間之相對生長係數皆呈極顯著，以樣區林木之胸徑為自變數，不僅可精確估算木麻黃林分各部位生物量，且其應用性較為廣泛。由各相對生長關係式估算木麻黃8年生林分幹量（乾重）為36.42~51.5lton/ha，枝量（乾重）為12.65~20.21ton/ha，葉量（乾重）為0.99~1.48ton/ha，根量（乾重）為10.21~15.31ton/ha，幹量：枝量：葉量：根量之比約為59:22:2:17，林分葉量偏低的原因或係由於東北季風吹襲致使林木之葉量大為減少，但木麻黃林分之基本葉量為何，尚有待進一步調查。

關鍵字

林分生物量 ； 木麻黃人工林 ； 海岸砂丘 ； 生長

並列摘要

The growth and biomass production of an 8-year-old casuarina stand at Miao-Li county was studied. Stratified-clip technique was used to obtain the growth data of sample trees which were selected from various DBH classes of six study plots (20×30m). The stand biomass was estimated by allometric equations.
The stand density of casurarina was over 5000 tress per hectare which resulted that most of the casuarina was composed of slender trees. Major vertical dry matter distribution of branches and leaves (branchlets) of the sampled tees are from 3.3-6.3m ground height Root depth was generally between 0-l20cm and the total root area was between 0.784-5.096 square meter. Total root area was normally propotional to the tree size. The crown projection was generally between 0.58-4.74 square meter. The crowns of most larger trees were oblique toward southwestern direction due to the northeastern monsoon which resulting the major root systems were toward northeastern direction.
Correlation coefficient among different growth characters were found positive and highly significant Estimations of the stem biomass (dry matter) ranged from 36.42 to 51.5ltonlha; the branches from 12.65 to 20.2 lton/ha; roots from 10.21 to 15.3ltonlha and the leaves from 0.99 to 1.48ton/ha. Although casuarina is an evergreen tree, significantly lower leaf biomass might be due to the winter northeastern monsoon which causes leaffall. A careful study on the seasonal changes of the casuarina leaffall is necessary.

並列關鍵字

Stand biomass ； Casuarina plantation ； Coastal sand-dune ； Growth