Page:Growing Black Locust Trees.djvu/25

Rh feet or so everything should be done to encourage volunteer growth. Weeds and low vines often afford such a desirable ground cover. The Japanese honeysuckle vine is often seen growing with black locust trees and almost always affording a beneficial ground cover. Contrary to a misconception, it rarely harms a tree by getting into the foliage. This vine is a very weak climber and should be clearly differentiated from the wild grape and kudzu, both of which are lusty climbers and commonly smother and kill trees.

(5) Provide shade for the tree trunks, if practicable. A dense growth of locust growing in deep, fertile soil well supplied with moisture, or locust trees with trunks shaded by slower growing heavy-foliaged species of trees as a rule are found to be thriftier and less subject to infestation.

(6) Protect young black locust from all grazing by livestock. It is a legume and palatable at all times of the year, and subject to heavy browsing, particularly in the dormant season, when green foliage is absent. Cattle and horses, as well as sheep and goats, browse freely on the locust twigs and branches and often break down young trees. It is also very essential to preserve a complete ground cover of vegetation and humus over the ground. By trampling, grazing and browsing, livestock quickly break up the protective cover, and the ground becomes hard and dry. This condition is very unfavorable to vigorous tree growth.

(7) Keep out fire at all times. The reason is obvious, and it should be noted specially that black locust is particularly susceptible to injury and death by burning. Young locust has a very thin bark, and the roots are shallow. Any removal of the vegetative cover from the soil will immediately be shown by its effect upon the vigor and life of locust trees, even if the fire is so light as not to cause direct injury.

Closely related is the effect of severe drought in lessening the vitality of black locust trees to a point where the borer readily overcomes the weakened resistance of the trees and severely injures or kills them.

(8) Prune back stagnated stands. As black locust is a vigorously sprouting species, it is good practice to cut clean slow-growing, stunted young trees up to 3 to 6 years of age. If this is done, preferably in the dormant season, the result should be vigorous sprouts that will be much freer of insect attack. The colonies of sprouts should be reduced to a single tree; midsummer is the best time for the cutting, as sprouting is then least vigorous.

Pruning early is a very important aid in producing a straight clean trunk. In midsummer of the second growing season after planting the one straightest and strongest central stem should be freed to grow singly by cutting off all other competing or framework stems. It is a great mistake to cut off the many weak laterals that will never compete as a central stem but are valuable in supporting the foliage and therefore furnish food for the growth of the main trunk. Vigorous growing trees might well be shaped by pruning in the first season, and conversely slow developing trees might not need pruning until their third year. Early and repeated