通过对赤峰示范区内杨树“小老树”的实地调查，对其成因进行了探讨，认为造林密度、土壤水分、养分、树种选择及抚育措施不当等是“小老树”形成的重要原因；同时提出了相应的改造模式，即更替树种、间伐、嫁接、建立混交林等具体措施。 Through the field investigation of the “small old tree” of poplar in Chifeng Demonstration Area, the causes of it were discussed, and it was considered that the reason of the formation of “small old tree” was the afforestation density, soil moisture, nutrients, improper tree selection and improper tending measures At the same time, a corresponding transformation mode was put forward, that is to say, specific measures such as replacement of tree species, thinning, grafting, establishment of mixed forests and so on.