北台灣福山試驗林陡峭林地之植群構造在不同微地貌的變化

Variation in Vegetation Structure for Different Micro-land- forms of a Steep Forest Plot in the Fushan Experimental Forest, Northern Taiwan

王相華(Hsiang-Hua Wang) ； 沈勇強(Yeong-Chium Sen) ； 高瑞卿(Yui-Ching Kao)

《台灣林業科學》 17卷1期 (2002/03) Pp. 99-112

https://doi.org/10.7075/TJFS.200203.0099

摘要

本研究探討植群構造與微地貌間的相關性。研究地點爲台灣北部福山試驗林內的一塊2ha的常綠闊葉林，該樑區地勢陡峭，跨越頂坡及漢谷，包含不同微地貌。樣區劃分爲7種微地貌（頂坡、上坡、下坡、山腳－溪谷、平緩山溝、陡峭山溝及崩塌地），並進一步比較植群構造（以枝葉層垂直結構、平均冠層高、林木胸高斷面積及密度爲代表）及孔隙面積在不同微地貌的變化。調查結果指出，不同微地貌在植群構造上有顯著差異。頂坡及上坡的有效土壤較深、坡度較爲平緩；相較於其它微地貌，其林分發育良好，有較高的平均冠層高度，林木胸高斷面積及密度也較火。相反的，孔隙則集中在有效土壤淺薄，容易受到沖蝕之陡峭山溝、山腳－溪谷。崩塌地尚處於林分發育初期之孔隙階段。頂坡及上坡有較高比例的立枯木分布，幹折及根拔林木的分布則無明顯的集中現象。邊坡的穩定性及地表沖蝕所造成的土壤干擾，是影響山區森林結構分化及孔隙分布的重要因子，特別是在地勢陡峭且雨量充沛的地區，例如台灣北部的福山試驗林。

關鍵字

微地貌 ； 孔隙 ； 枯死木 ； 植群構造 ； 土壤干擾

並列摘要

The relationship between micro-landforms, and vegetation structure was examined in a 2-ha plot established on a slope extending from a mountain crest to bottomland in an evergreen broadleaf forest in the Fushan Experimental Forest, northern Taiwan. Seven micro-landforms (crest, upper slope, lower slope, foot slope- bottomland, smooth gully, steep gully, and landslide) were recognized in the plot. Vegetation structure (represented by vegetation height profile, aver age canopy height, basal area of woody plants, and density of woody plants) and areas of gaps were compared among different micro-landforms. There was significant difference in vegetation structure among micro-landforms. The vegetation was better developed (higher average canopy height, larger basal area and density of woody plants) on the crest and upper slope where the effective soil was deeper and the inclination was flatter. In contrast, there were greater areas of canopy gaps recorded in the steep gully, foot slope-bottomlands and landslide patches where the effective soil was shallower due to soil erosion. Standing dead trees tend to aggregate on the crest and upper slope, while snapped and uprooted trees show no obvious aggregation. In conclusion, the regime of soil disturbance is the predominant factor influencing the vegetation structure and distribution of canopy gaps among different micro-landforms. This is apparent in an area of steep slopes with plentiful rainfall in Taiwan, for example in the Fushan Experimental Forest in northern Taiwan.

並列關鍵字

micro-landform ； gap ； dead tree ； vegetation structure ； soil disturbance