论文部分内容阅读
五、六十年代初期,博州垦区一些风沙危害严重的团场,栽植的农田防护林带多由8—20行树木组成,株行距1×1.5米,树种有杨树、柳树、白榆、沙枣等,林带宽16—30米。在这种密度下,林木生长不良,分化严重,防护效能大大降低。如83团良繁连的10行农田防护林带,初植时为杨、柳、
In the 1950s and early 1960s, some wind farms in Bozhou Reclamation Area were seriously endangered. The farmland shelterbelts were mostly composed of 8-20 trees with spacing of 1 × 1.5 meters and poplar, willow, elm and sand Jujube, forest bandwidth 16-30 meters. In this density, poor growth of trees, severe differentiation, greatly reduced protective effectiveness. Such as 83 Mission Liangfan even 10 lines of farmland shelterbelts, when the plantation of Yang, Liu,