【摘要】 为了认识零星分布在内蒙古东部的天然沙地油松林的林分结构,以便于更好地保护该防风固沙林,于2008年在浑善达克沙地东部建立了面积为4hm2的永久样地。对胸径1cm以上的每株树木进行了定位监测。样地内共监测到不分支的个体数7363株,树种组成较单一,仅10个树种。个体数、平均胸径、胸高断面积、频度和重要值结果显示:油松(Pinus tabulaeformis)、山杏(Prunus armeniaca)占有绝对优势。用空间结构参数:混交度、大小比数和角尺度对该林分的空间结构进行了分析。结果表明:浑善达克沙地天然油松林分的平均混交度为0.44,优势树种油松和山杏的混交度低于平均混交度水平;绝大部分树种的大小比数在中庸状态左右波动,说明树种在垂直方向上分化不明显;样地内所有个体的平均角尺度和9个树种的平均角尺度都大于0.517,说明林分整体和绝大部分树种都呈聚集分布的格局。这种空间结构特点可能与山丘沙地的微生境有关。更多还原

【Abstract】 A 4-hectare Pinus tabulaeformis permanent sample plot was established on Eastern Hunshandake sandy land in 2008 in order to study the stand structure of P.tabulaeformis forests fragmentarily distributed on the sandy land in the Eastern Inner Mongolia Plateau,which play a key role in sand fixation and climatic regulation.All the trees with diameter at breast height(DBH) equal to or more than 1cm were located and monitored.There are 7 363 genotype individuals in the stand(sample plot),belonging to 10 tree species.P.tabulaeformis and Prunus armeniaca are obviously dominant species in terms of species abundance,average DBH,basal area,frequency and importance value.The spatial structure parameters such as mingling degree,neighborhood comparison,and uniform angle index were applied to describe the spatial structure of the stand.Results showed that the average mingling degree of the stand was 0.44,and the mingling degrees of P.tabulaeformis and P.armeniaca were both lower than the average mingling level.The neighborhood comparison of most tree species fluctuated around a moderate level,and the uniform angle index of all individuals and 9 tree species was above 0.517.It indicates that individuals of the same tree species are often clustered,and the distribution patterns of the stand and most species are aggregated in this stand.The stand structure might be closely related with the microhabitats of stabilized dunes in Hunshandake area.更多还原