Shaping and pruning of Robinia pseudoacacia

Robinia pseudoacacia is an excellent tree species for afforestation and afforestation in our province because of its fast growth, strong adaptability and excellent quality. But Robinia pseudoacacia sprouting is very strong, if not pruned, it will grow full of branches, not ventilated, thus affecting the growth rate. According to the observation, the average annual growth of Robinia pseudoacacia after correct pruning is 72cm, while that of no pruning is only 49cm, which is pruned continuously, which is 3-5 years earlier than that without pruning. In order to achieve this goal, attention must be paid to shaping and pruning.

Under the condition of natural growth, Robinia pseudoacacia has strong branching power and exuberant growth, often forming a wide oval crown, but most of the trunks are low and have too many branches, forming "small old trees". Shaping is to straighten the trunk, and the lateral branches competing with the trunk should be trimmed from the first winter or the second spring after planting, until the trunk height is more than 6m after 8 years, reaching the civil material standard on time.

The big seedlings of Robinia pseudoacacia used for landscaping are generally strong, and the one-year-old branches that are strong and upright at the top can be selected first as the trunk to extend the branches, and then, the apex of the shoots should be cut off, and the weak branches should be re-pruned (but not too heavy, otherwise it is not easy to grow strong branches under the cut). If there are small and weak branches near the shearing mouth, it is appropriate to cut off some of the branches, and the upper side branches are cut short one by one, so that the apex is not higher than the main shearing mouth.

Pruning

The time and quantity of pruning should be determined according to the purpose of afforestation. For general afforestation, pruning should be carried out after the young forest is closed, and the greening and shelterbelt on the four sides should be pruned properly in the first 3 years in order to cultivate a higher trunk and prevent excessive shade. The first technique of pruning is thinning: for example, the trunk of Robinia pseudoacacia less than 2 years old is lower, and the vigorous and erect branches are generally selected as the trunk, and the rest of the branches are thinned according to different conditions, according to the crown-to-dry ratio (2-3 years old 3-year-old 4-6-year-old 1:1 2:3, 8 years old) after the trunk was trimmed to a certain height, the stout competitive branches, overgrown branches, erect branches and some overdense side branches, drooping branches and dead branches in the upper part of the crown were removed. The second is to cut off the upright and strong side branches in summer, according to the principle of keeping the pressure weak, going straight and keeping flat, heavy cutting in the upper part of the crown and light cutting in the lower part, leaving twigs under the cut mouth, which can not be thinned off from the base, so as to avoid wind break or weak growth of the main shoot. For the young trees with trunk heading and flat stubble in winter or spring, when the strong branches germinated at the cutting point grow to about 30cm, the strong branches that have been standing are left for whole branch culture, and the rest can be cut off for about 1 inch 3 times in a row for 3 times. The thick branches under the canopy should be cut off year by year, and it is best to leave two thin branches.

Pruning sprouting strip

After pruning, the strong and long branches on the trunk or main side branches should be coring or cutting; for the sparse branches at the base of the trunk and the top of the trunk that starts in winter, the new buds and sprouts should be cut off as soon as possible. Pruning should be carried out in summer, from early June to early July, which has the advantages of small wound and fast healing, and generally no longer germinates a large number of branches, which is beneficial to the growth of young trees. Pruning should not be overweight, should be close to the trunk, leaving no stakes, so as not to form knots. The use of tools should be sharp, the wound should be smooth, so that the branches should not split.