天童常绿阔叶林林隙的形成特征

对天童常绿阔叶林内林隙的形成特征进行了研究,结果表明：该地区林隙的线密度为17.08个&;#8226;km^-1，扩展林隙所占面积比例为15.42％，冠空隙所占的比例为5.46％.冠空隙的年形成频率为0.287％，林隙形成的返回间隔期为348.4 a左右.林隙的面积普遍偏小，扩展林隙面积在39.3～251.2 m²之间，平均面积为106.32 m²，冠空隙大小变化在11.8～131.9 m²之间，平均面积为37.68 m².树木枯立、风灾以及对病树的人为择伐是该地区林隙的主要形成方式，木荷、马尾松、栲树和石栎等乔木层常见种类是其主要形成木.在山坡上部、中部和下部等不同地形条件下分别以风灾、枯立和择伐为主要方式形成林隙.调查的41个林隙中，每个林隙的形成木平均拥有量仅为1.71株.形成木径级主要分布在20～40 cm范围内，平均基径为28.93 cm.

Forming Characteristics of Gap in an Evergreen Broad-leaved Forest in Tiantong National Forest Park,Zhejiang Province,Eastern China(Chinese)

Gap is a common disturbance regime in forest ecosystem.This paper studied their forming characteristics in an evergreen broad-leaved forest in Tiantong National Forest Park,Zhejiang Province.The results showed: the linear gap density in the forest is 17.08 gaps/km,the expanded gaps occupy 15.42%,and canopy gaps occupy 5.46%.The yearly gap forming frequency is 0.287% and the forming rotation is about 348.4 a.The gap size is smaller than other regions,its expanded gaps vary from 39.3 m2 to 251.2 m2 and the average size is 106.32 m2.Canopy gaps vary from 11.8 m2 to 131.9 m2 and the average size is 37.68 m2.Standing litter,wind damage and selective lumber are main manners of gaps formation,most of gap-makers are Schima superba,Pinus massoniana,Castanopsis fargesii,Lithocarpus glaber,Lithocarpus harlandii,and so on.They are all dominant species in tree layer in this region.The types of gap-makers are different at different landforms.The average gap-maker number in each gap is 1.76,the main distribution range of Base Diameter(BD)of gap-makers is from 20 cm to 40 cm,and their average BD is 28.93 cm.