关键词: 坝上地区, 退化防护林, 杨树, 改造方式, 政策建议

Abstract: Preliminary results of protection forest construction were achieved in Bashang district of Zhangjiakou city and this area is regarded as key section of Beijing-Tianjing-Hebei shelter forest planning.In recent years,some problems have appeared in poplar protection forest,for example,old-aged forest and degenerated functions.In the paper,four aspects including degenerated poplar protection forest situation,degeneration reason,transformation measure and countermeasure are discussed in order to provide reference for follow-up protection forest construction.

Key words: Bashang district, degenerated protection forest, poplar, transformation measure, countermeasure