在东北林业大学帽儿山实验林场.对10年生的水曲柳落叶松带状混交林及纯林进行了调查．结果表明：水曲柳在混交林中表现出明显增产,高生长比纯林增加12.1％～25.5％．胸径生长增加12.7％～32.3％.落叶松在混交林中也表现出增产的趋势．高生长比纯林增加4.1％．胸径生长增加12.5％.种间关系属双方有利.运用简单竞争指数对树种的竟争程度进行比较表明：在混交林中仅用地上部测树因子构造的简单竞争指数并不能很好地体现树种间地上和地下部的综合竞争程度，这种指数主要体现了树种间地上部竞争程度。 In Maoershan Experimental Forest Farm of Northeast Forestry University, 10-year-old mixed forest of Ash and Larix principis-rupprechtii were investigated. The results showed that Fraxinus mandshurica increased significantly in mixed forest, and its height increased by 12.1% -25.5% compared with pure forest. The DBH growth increased by 12.7% ~ 32.3%. Larix also showed an increasing yield in the mixed forest. High growth increased by 4.1% over pure forest. The growth of DBH was increased by 12.5% ​​.The interspecific relationship was favorable to both sides.The comparison of competitive degree of tree species by using simple competition index showed that the simple competition index constructed by measuring tree factor in aboveground part of mixed forest did not reflect the difference between species The degree of overall competition above and below the ground, which mainly reflects the degree of competition between above-ground shoots.