松材线虫入侵后黑松林分结构特征的变化

The variation of stand structure of Pinus thunbergii forest after the invasion of Bursaphelenchus xylophilus

自1992年发现松材线虫入侵浙江舟山岛以来,现已有大量黑松死亡。为了把握松材线虫入侵后黑松林的林分结构特征,笔者对舟山长岗山的黑松林进行了大样地(100 m×100 m)群落调查。结果表明:20世纪50年代营造的黑松纯林已经演变成针阔混交林,乔木层树种更加丰富,多样性有所增加。但是,落叶阔叶乔木数量众多,在林冠层占据较大优势,常绿阔叶乔木数量较少,并且主要分布在乔木层的中下层。林分的混交程度较差,缺乏绝对优势的种群,林木整体表现为聚集分布,说明林分尚处于演替的前期。林分要演替成常绿阔叶林需要较长期的过程,为了加速林分演替,在较短时间内恢复当地的森林生态系统,建议适当补植一些海岛地带性植被的乡土树种。

The Invasion of Bursaphelenchus xylophilus on Zhoushan island resulted in the death of Japanese black pine （Pinus thunbergii） in 1992. With a plot investigation （plot size 100 m ×100 m） in Changgang Mountain, the stand structure of P. thunbergii forest was studied. The results showed that the past P. thunbergii forest now became a mixed conifer and broadleaved forest with an increasing of species richness and plant diversity. The deciduous broadleaf trees were the majority and had a relatively large advantage in the forest canopy. However, the evergreen broadleaved trees were the minority and mainly distributed in the middle and lower layer. The forest stands, lack of dominant species, was an aggregation distribution with low mixed degree. The above results showed that the forest is still in the early succession and needs a long - term process for the development of evergreen broadleaved forest. In order to speed up the forest suc- cession and restore the local forest ecological system as soon as possible, we suggest that it is important to replant some island zonal vegetation selected from the native tree species.