毛白杨是华北地区老百姓都非常喜爱的优良的乡土树种。它最适宜的栽植时间是春季和初冬。但是在特殊情况下，有时也会在非适栽期栽植，而且要求保活。例如，１９９３年春季，山东德州市宋官屯镇境内１０４国道改线工程，４月８日路基土方工程才基本峻工。此时绝大多数的树... Populus tomentosa is a very good native tree species loved by people in North China. It is the most suitable planting time in spring and early winter. However, under special circumstances, planting is sometimes carried out on non-suitable land and it is required to keep it alive. For example, in the spring of 1993, the state-owned 104 National Road rerouting project in Songguan Tunzhen, Dezhou, Shandong Province, basically finished its work on April 8. At this time the vast majority of trees ...