中文摘要：

以长白山北坡林线为研究区，选择4块样地（83个样方）进行岳桦种群径级结构与土壤理化性质关系的研究。采用单因子方差等方法分析土壤理化性质（有机质、全氮、全磷、砾石含量）和岳桦种群（灌丛和乔木）径级结构的关系，采用相关分析法做岳桦种群与土壤性质的动态变化分析。结果表明土壤因子对岳桦种群的扩张有一定的制约作用，但不足以决定林线的进退，岳桦通过不断调整生活型克服土壤约束以应对气候变化。

英文摘要：

This paper, taking the treeline of northern slope of Changbai Mountains as the research object, selected 4 plots （83 quadrats） to study diameter class structure of Betula ermanii population and soil physical and chemical properties. Four indices of soil properties （SOM, TN, AN and gravel contents） and diameter-class structure of two life forms （shrub and single-trunk） were analyzed by ANOVA, correlation analysis and other statistical analysis. The relationships between population dynamics and soil change were investigated by correlation analyses. The results showed soil physical and chemical properties on different quadrats had obvious difference with different expansion of Betula ermanii population. Soil factor had a certain restrictive effect on population dynamics. However, soil factor did not play a crucial role in treeline shifts and population expansion. The gradual weakening of soil properties has an effect on treeline shifts with the passage of time. The Betula ermanii population tended to continuously adjust its life forms to adapt air temperature change in order to overcome soil restrictions.