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内蒙古呼伦贝尔盟红花尔基林场现有樟子松纯林82000ha,长势良好。但1986年6月至1987年5月,出现了大面积枯死现象,20年生以下的天然林枯死率100％。作者按林分年龄、坡向、坡位、坡度取样,分析了土壤含水量,调查枯死现象与林地环境因子和立地条件之间的相关性。结果证明,1986年的严重干旱使土壤含水量低于樟子松的含水量临界点,造成樟子松大面积枯死。1986降雨量为228.3mm,比年平均值334mm低105.77mm。在樟子松根系分布层中的含水量仅有2.288％～2.360％。郁闭度小或过大的林分因旱致死的多。天然林分因树木根系发育良好,其抗旱力强于人工林。混交林的抗旱力强于单纯林。20年生以下的林分旱死的多,10年生以下的林分旱死的更多。阴坡未发现受害的。
Inner Mongolia Hulun Buir League Honghuaerji forest existing Pinus sylvatica pure forest 82000ha, growing well. However, a large area of withering occurred between June 1986 and May 1987, and the dead rate of natural forests below 20 years old was 100%. The authors sampled the forest age, aspect, slope position and slope, and analyzed the relationship between soil water content, the phenomenon of withered dead and the environmental factors and site conditions of forest land. The results showed that severe drought in 1986 made the soil water content below the critical point of water content of Pinus sylvestris var.mongolica and caused the large area of Pinus sylvestris to die. 1986 rainfall was 228.3mm, 105.77mm lower than the annual average of 334mm. The water content of Pinus sylvestris var. Mongolica was only 2.288% -2.360%. Canopy density is too small or too large due to drought and more forest. Natural forest due to the well-developed tree roots, the drought-resistant than the plantation. Drought resistance of mixed forest is stronger than pure forest. The forests below 20 years of age are more droughts and the trees under 10 years of age are even more droughts. Not found on the shady slope.