How to Carry Out Sprout Regeneration of Black Locust? Detailed Practical Technical Points

1. Site clearing. After clearcutting black locust, a large amount of residues, shrubs and weeds accumulate on the site, which are obstacles to sprout regeneration and should be cleared in time. The main purpose is to improve site conditions and sanitation, create a favorable environment for young tree growth, and promote the young stand to close its canopy as soon as possible.

2. Forest land enclosure. To shorten the forest cultivation cycle, comprehensive enclosure measures are adopted for black locust clearcut sites. Cattle and sheep specifically browse the tender shoots of young trees and cause extremely severe damage to black locust sprouts, so dedicated personnel must be assigned for supervision and protection, grazing must be strictly prohibited; mowing and firewood gathering, and man-made damage to trees are strictly prohibited; 2,4-D butyl ester herbicide must not be used in the forest land or within 200 m nearby.

3. Sprout thinning and stem selection. Suitable conditions on the clearcut site cause a large number of adventitious buds and dormant buds of black locust to sprout, so sprout thinning and stem selection must be carried out in time to retain sprout-origin seedlings and keep root-sucker seedlings as few as possible. The first thinning should leave a high density of seedlings to facilitate canopy closure as soon as possible. The plant and row spacing should be kept at about 1 m, with 666 plants preserved per mu.

4. Bud rubbing and pruning. Bud rubbing should be carried out in time in the first year. Bud rubbing is a tending measure that promotes young tree growth and cultivates a good trunk form. The specific method is that when the tender buds sprouting on the young tree trunk have not yet lignified, wipe off the tender buds below 2/3 of the trunk to prevent nutrient dispersion, which is beneficial to young tree growth and cultivates high-quality knot-free timber. Pruning begins in the second year. Pruning is a tending measure of cutting off dead branches or part of the living branches, and is an important means of regulating the internal nutrition of trees. Timely and appropriate pruning can promote rapid growth of the main trunk, cultivate a good trunk form, reduce knots, improve wood quality, and at the same time play a role in reducing pests and diseases. Pruning can be carried out during the vigorous summer growth period, when young trees grow vigorously and wounds heal easily. Pruning tools can be sharp pruning shears, cutting flush close to the trunk. For pruning intensity, when tree height is below 3 m, the crown-to-trunk ratio should be maintained at 3:1; when tree height is 3-6 m, it is 3:2; above 6 m, it is 2:1.

5. Tending thinning. Black locust from sprout regeneration, after sprout thinning and stem selection, bud rubbing and pruning, quickly closes into forest, tree crowns overlap and intersect, understory light is lacking, expansion of individual tree crowns is severely blocked, and they compete with each other for light, water and nutrients, so light-transmission tending must be carried out in time. In principle, adopt thinning where dense and leaving where sparse, thinning small and leaving large, removing inferior and leaving superior. Tending intensity should not be too large, and it is appropriate to open up the tree crowns.

Growth tending is a tending cutting carried out over a long stage before the stand reaches mature age or even before final felling for forest maturity, with the main purpose of regulating stand density and accelerating diameter growth of black locust. It is required to select and retain the superior and fell those trees that are poorly developed, crooked in trunk form, and have no prospect for cultivation. The cutting intensity can be appropriately larger, so as to promote volume growth of black locust, improve tree quality, and increase economic benefits.