水曲柳天然更新及其影响因子

摘要

在长白山北部地区采用样地调查方法,对5种林分类型中的水曲柳天然更新进行了调查,结果发现:水曲柳在所有林分中更新株数和更新频度均超过其他树种,在针叶树人工林下水曲柳更新最好,更新株数达12 261 ～50 012株·hm-2,而在软硬阔混交林下更新相对较差(3 329株·hm-2),在自身林下更新最差(1 852株·hm-2)；草本盖度是影响水曲柳更新的重要因素,水曲柳更新数量与草本盖度呈明显负相关；水曲柳在母树附近更新不良,距母树(S)S＜5 m处仅有9.5％的更新幼苗出现.经室内种子发芽试验测定,水曲柳未分解凋落叶水浸液在高质量比时,对自身种子发芽抑制作用明显.从而说明,过高的草本盖度和凋落物自毒作用可能是导致水曲柳自身林下更新不良的主要原因.%With sampling plot method,we investigated natural regeneration of Manchurian ash (Fraxinus mandshulica) for five forest types in the north region of Changbai Mountain.The results showed the regeneration density and frequency of ash are higher than those in other tree species in five forest types.The regeneration density of ash is higher in the conifer plantation with 12 261-50 012 tree · hm-2 than that in the secondary forest with 3 329 tree · hm-2 and that in the ash forest with 1 852 tree · hm-2.The coverage of herbage is the important factor controlling ash natural regeneration,and the amount of ash seedlings has negative relative with the coverage of herbage.The natural regeneration of ash decreased with the distance to mothertree.There are only 9.5％ of ash seedlings at a distance of ＜5 m to mothertree.The results of seed germination showed when the concentration of ash leaves extraction is higher,seed germination of ash will be inhibited significantly in the sowing experiment.Thus,the regeneration of ash inhibited in the ash forest may be derived from the higher coverage of herbage and autointoxication of ash litter.