Generally speaking, competitive branches that affect the growth of main branches are subtracted or truncated.

Prune once a year after afforestation for 4-5 years. Generally, it is carried out before the deciduous trees germinate in spring. At this time, the trees have stopped growing, pruning is not easy to tear the bark, and the sap does not flow. In addition, in the second spring, the healing tissue forms quickly and the wound heals quickly, which is beneficial to the growth of new shoots and can reduce the chance of infection by pests and diseases. Adventitious buds often germinate near the wound where the branches have been trimmed, and the shoots are pulled out. It is best to trim it in August and September of that year.

In the year of planting, plastic drying is started to reduce or shorten the competitive branches that affect the growth of the main branches. If the trunk is not obvious or the tip is broken, a strong bud should be left in the shade, and the lcm should be shortened to erase the buds below 1 ~ 2 years1.5m. Generally, it is required to prune rough competitive branches, liberate weak branches, and slightly prune and chop the side branches. After 3 ~ 4 years, it can be trimmed to the height of the tree. In the fifth year, the lateral branches at the lower part of the trunk are gradually pruned, and the ratio of crown to stem is 1, 2. From the ninth year to the main cutting period, the crown height is kept at the level of 1 3 of the tree height until the main cutting. Under normal circumstances, poplar can be pruned to more than 10m.