长白山暗针叶林林隙一般特征及干扰状况

对长白山暗针叶林林隙一般特征和干扰状况进行了研究。结果表明：长白山暗针叶林林隙的线状密度为２１．１５个／ｋｍ，扩展林隙所占的面积比例为２９．４５％，冠空隙所占的面积比例为１５．８１％；冠空隙的年干扰频率为０．２４％，干扰轮回期为４１６．７ａ左右；冠空隙的大小变化在１７．９—３４０．３ｍ＾２之间，＜１００ｍ＾２的冠空隙个数较多，冠空隙的平均面积为９３．６０ｍ＾２；扩展林隙的大小变化在４３．６—４８２．３ｍ＾２之间，５０一２００ｍ＾２之间的扩展林隙个数较多，扩展林隙的平均面积为１７４．３４ｍ＾２；暗针叶林林隙形成的主要方式是风倒；在长白山暗针叶林中，大多数林隙是由２—６株形成木形成，其中由３株形成木形成的林隙员多，单株或７株以上形成木形成的林隙数量很少；在暗针叶林中，１０一４０ａ前这段时间形成的林隙较多，特别是２０一３０ａ期间形成的林隙员多。其它阶段形成的林隙较少；暗针叶林的林隙大多是由臭冷杉、落叶松和鱼鳞云杉形成。径级在１０一３０ｃｍ之间，高度在２５—３０ｍ之间的主林层树木形成林隙的可能性最大。暗针叶林林分组成、林隙干扰方式和程度随海拔高度的变化而变化。

Gap Characteristics and Disturbance Regime in a Dark Coniferous Forest in Changbai Mountain Areas

Gap characteristics and disturbance regime in a dark coniferous forest in Changbai mountain areas were studied. The result showed: the linear gap density in the forest was 21 15 gaps/km, the expanded gaps occupied 29 45%, and canopy gaps occupied 15 81%. The yearly gap disturbance frequency was 0 24% and the disturbance rotation was 416 7 years. Canopy gaps varied from 17 9 to 340 3m 2 and the majority were less than 100m 2. Expanded gaps varied from 43 6 to 482 3m 2 with most between 50m 2 and 200m 2. The most important cause of gap formation was uprooting from blow\|down, and the secondary cause was breakage at the trunk base. Most gaps were formed by 2~6 gap makers. Major gap makers were Abies nephrolepis, Larix olgensis , and Picea jezoensis . The probability of gap development was greatest when the trees in the canopy layer were 10~30 cm DBH and 25~30m high. In the dark coniferous forest, gap ages were mostly 10 to 40 years and there were very few over 60 years. This indicates that gaps were filled with regenerated young trees so that they were difficult to distinguish from the normal stand. The stand structure, gap disturbance cause, and degree varied with elevation, with increased gaps above 1350 m.