白龙江沙滩林场高山林线主要森林群落结构与数量分布

Main Forest Population Structure and Quantitative Distribution in Alpine Forest Line of Bailongjiang Shatan Forest Farm

高山林线是一种典型的生态交错带,是对气候反映最敏感的地区之一。通过对白龙江沙滩林场高山林线主要森林种群结构的研究,结果表明:(1)沙滩林场高山林线区域植被分布比较明显,随着海拔的升高,依次是乔木林、乔灌混交林、灌木林、高山草甸,最后是裸岩;群落垂直分层最上层以岷江冷杉为主,中层主要是杜鹃,下层以小灌木为主。(2)研究区主要以岷江冷杉和杜鹃为建群种,重要值分别是25.99%和27.73%,两者之和超过其他所有物种之和,相对优势度分别为39.39%和29.08%,两者之和占所有植物优势度的70%左右。(3)从群落的高度级分布的统计结果来看,高度级结构呈倒J型分布。高度级第Ⅰ级的植物株数最多,其中岷江冷杉幼苗占31.9%,杜鹃幼苗占28.6%。

The alpine timberline is a typical ecological interlaced zone and one of the most sensitive areas for climate changes.The research on the structure of the main forest populations in the alpine timberline of Bailongjiang sandy forest farm shows that:(1)The distribution of vegetation in the alpine timberline of the Shatan forest farm is obvious.With the elevation,the order is arbor forest,mixed forest,shrub forest,alpine meadow,and finally bare rock.The uppermost layer of vertical stratification for community is dominated by Abies faxoniana,the middle layer is mainly Rhododendron simsii,and the lower layer is mainly small shrub.(2)The study area is mainly composed of Abies faxoniana and Rhododendron simsii.The important values of are 25.99%&27.73%,respectively.The sum of the two is higher than that of all other species.The relative dominance is 39.39%&29.08%,respectively.The sum of the two accounts for about 70%of all plant dominance.(3)From the statistical results of the height distribution of the community,the height structure is inverted J-shaped.The number of plants of the first grade is the highest,of which 31.9%are from Abies faxoniana seedlings,28.6%are from Rhododendron simsii seedlings.