解放以来,我州累计造林虽达1,250多万亩,但保存面积仅有300万亩左右,保存率不到25％,经济效益较低。究其原因,我认为无外乎自然因素和人为因素两个方面。就自然因素而言,冬春旱严重和霜雪危害,对提高我州造林成活、保存率影响极大。如冬、春旱严重的年成,个旧倘甸、鸡街及建水、开远、蒙自坝区两山等地区的幼苗旱死率竟高达100％。又如,1977年初春的低温寒害,使前卫林场海拔一千五百米以上的近万亩人工思茅松林几乎 Since the liberation, although there have been more than 12,500,000 mu of afforestation in our county, the preserved area is only about 3 million mu, the preservation rate is less than 25%, and the economic benefits are low. The reason, I think nothing less than natural factors and human factors in two aspects. In terms of natural factors, winter and spring drought and frost damage, to improve the survival of the state afforestation, save a great impact. In winter and severe drought years, the mortality rate of young seedling in Gejiudandian, Jixi and Jianshui, Kaiyuan and Mengzi dam areas is as high as 100%. In another example, the cold spring in early spring of 1977, so that avant-garde forest farms of more than 1,500 meters above sea level of nearly Manchu pine plantations almost