在营造防护林时,除了遵循适地适树的原则外,在树种搭配上一般需注意以下几个方面: 1.速生树种和长寿树种的搭配。这种搭配可使防护林能迅速而又长期稳定地起到防护作用。在新疆,速生的杨树林带一般在十五年就开始衰弱。因此,营造防护林带就要考虑榆杨树混交或白腊树混交,橡树、杨树混交等。一般速生树和长寿树的比例可以各 In the construction of shelterbelts, in addition to follow the principle of suitable tree, in the tree with the general attention should be paid to the following aspects: 1. Fast-growing tree species and longevity match. This kind of collocation can make the shelter quickly and long-term and stable play a protective role. In Xinjiang, the fast-growing poplar forests generally start to weaken in 15 years. Therefore, to create shelterbelts should consider elm hybrid or white wax mixed, oak, poplar and other hybrid. General fast-growing trees and longevity can be the proportion of trees