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日照市现有松林30万亩,其中黑松林5万亩,因1987年11月26日—28日突然降温15.9℃,遭受冻害的约有3万亩,平均冻害率为45.27％,冻害指数23.17,死亡率0.77％,这是自五十年代初引种黑松以来首次发生的严重冻害。为了进一步认识黑松对低温的适应性,现将调查结果报告如下:一、冻害原因与症状1987年11月下旬,因受西伯利亚南下冷空气影响,我市突然出现大风雪天气,西北风8级以上,3天内降水(雪)量14.6mm,平均气温下降15.9℃,极端气
Rizhao City, the existing 30 million mu of pine forest, of which 50000 acres of black pine forest, as November 26, 1987 -28 suddenly cooled 15.9 ℃, suffered frost damage of about 30,000 mu, the average rate of frostbite was 45.27%, frost damage index of 23.17 , With a mortality rate of 0.77%, the first serious freeze since the introduction of Pinus thunbergii in the early 1950s. In order to further understand the adaptability of the black pine to low temperature, the survey results are reported as follows: First, the causes and symptoms of frost damage In late November 1987, due to the cold air south of Siberia, the city suddenly appeared snowstorm, the northwest wind 8 Level above, 3 days precipitation (snow) amount 14.6mm, the average temperature dropped 15.9 ℃, extreme gas