论文部分内容阅读
花旗松(Pseudotsuga menzisii)是世界上最有价值的重要用材树种之一。1984年,我园引入美国落基山花旗松种子进行引种。通过5年培育,该树种已能在延安安全越冬,无病虫危害,生长良好,平均地径1.59cm,平均树高0.43m,最大地径达2.15cm,最高达0.78m。引种地与美国落基山地区气候条件相比较,其气温在原分布区之间,极端最低温偏低9℃,最高温偏低4℃左右,年降水量相差较多,在2—3倍以上,海拔高和无霜期在原主要分布区之间。育苗采用塑料棚容器直播。1年生苗高6.1cm,当年冬季在塑料棚内越冬,翌年初春揭掉薄膜。2年生苗高12.2cm,地径
Pseudotsuga menzisii is one of the most valuable timber species in the world. In 1984, I Park introduction of the United States Rocky Mountain Douglas Fir seeds for introduction. After five years of cultivation, the tree species has been able to win a safe winter in Yan’an without any pests and diseases and grow well with an average diameter of 1.59cm and an average tree height of 0.43m with a maximum diameter of 2.15cm and a maximum of 0.78m. Compared with the climatic conditions of the US Rocky Mountain, the temperature of the introduced area is between the original distribution areas, with the lowest extreme low and the lowest extreme low 9 ℃ and the highest low and low 4 ℃, the annual precipitation is quite different at 2-3 times or more, High altitude and frost-free period between the original main distribution area. Nursery plastic containers live broadcast. 1-year-old seedling height 6.1cm, then wintering winter in the plastic shed, the early spring of the following year to peel off the film. 2-year-old seedling height 12.2cm, diameter