１农防林更新改造的由来长春市现有农防林６．５万ｈｍ２，随着时间的推移，有部分在三北一期工程或之前营造的农防林已进入成熟和效益衰退阶段，还有部分残次、病虫害严重的林带需要更新改造。针对该问题，长春市政府指示长春市林业局要把农防林更新改造列入重要议事日程... 1 The origin of the renovation of agricultural defense forest Changchun City, the existing agricultural anti-forest 65000 hm2, with the passage of time, some in the Three North Phase I project or before the construction of agricultural defense forest has entered the stage of maturity and efficiency decline, There are still some residues, pests and diseases of the forest need to update the transformation. In response to this problem, Changchun Municipal Government instructed Changchun Forestry Bureau to update and rebuild agricultural and forestry forests on the agenda.