木兰围场华北落叶松人工林林隙对天然更新的影响

为了阐明华北落叶松人工林不同林隙大小对更新的影响规律,对木兰围场低效华北落叶松人工林林隙内苗木更新特性进行了研究。结果表明:林隙内更新苗的主要种类有华北落叶松、山杨和油松。华北落叶松和山杨的密度在林隙面积为120~140m2时最大,达到2 411株/hm2;而油松的密度在林隙面积为20~40m2时最大,为196株/hm2。随着林隙面积的增大,华北落叶松和山杨大径级和大高度级更新幼苗数量基本呈现增加的趋势,在林隙面积达到160~180m2时达到最大值;而油松在40~60m2时达到最大,径级大于2cm的更新苗密度为69株/hm2。

Effects of gap on natural regeneration of Larix principis-rupprechtii plantation in Mulan Weichang

Seedling regeneration properties of inef ficient Larix principis-rupprechtii forest in Mulan Weichang were researched in order to clarify gap size on update rules of Larix principis-rupprechtii forest .The results showed renewed seedlings within gaps consist of Larix principis-rupprechtii ,Populus davidiana and Pinus tabulaeformis .Larix principis-rupprechtii and Populus davidiana density in the gap area range from 120 to 140 m2 is maximum ,reaching 2 411 individuals per hectare .But Pinus tabulae f ormis density in the gap area ranging from 20 to 40 m2 is maximum ,with 196 individuals per hectare .With the in-crease of gap size ,the seedling number of Larix principis-rupprechtii ,and Populus davidi-ana of large diameter and height class showed an increasing trend ,reaching the maximum value in the gap area up to 160 to 180 m2 while Pinus tabulaeformis reached the maximum value at 40 to 60 m2 ,with the seedling density of 69 individuals per hectare when diameter at 2 cm .