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白桦分布于我国东北、华北和西南山区,在内蒙古境内山地分布很广,无论面积或蓄积量,白桦林仅次于兴安落叶松林。大青山中九峰山的白桦林较发达,是山地森林的主要类型。九峰山山地的白桦林几乎占据了海拔1200～1900米的阴坡及半阴坡,多发育在凹地中,其上部山脊为虎榛子,下部为沟谷草甸。分布范围内上部是青海云杉——白桦混交林,中部为白桦——山杨混交林,下部为白桦纯林。白桦林是九峰山主要的山
Betula platyphylla distributed in northeastern China, north China and southwestern mountainous areas, mountainous areas in Inner Mongolia are widely distributed, regardless of area or volume, birch forest second only to Larix gmelinii forest. Big Castle Peak Jiufeng Mountain birch more developed forest is the main type of forest. The birch forest in Jiufeng Mountain occupies almost the shady slopes and semi-shady slopes of 1,200 to 1,900 meters above sea level, mostly in the concave land. The upper ridge is tiger hazelnut and the lower part is the valley meadow. The upper part of the distribution range is the spruce-birch mixed forest in Qinghai, the birch-birch mixed forest in the middle part, and the pure birch in the lower part. Birch forest is the main mountain of Jiufeng Mountain