Page:Growing Black Locust Trees.djvu/27

Rh soft water and stir well. Early spring, about the time the young leaves begin to unfold, is the best period for applying the spray.

The trees should be cut during the period from late fall to late winter, in order to promote vigorous sprouting the following spring. The sprouts which grow following midsummer cutting do not usually become sufficiently hardened to withstand the winter freezings. It is also important to cut stumps low, only a few inches above the ground.

It is only the heartwood of black locust that is extremely durable in contact with soil. The sapwood decays more rapidly. It is usually very narrow, consisting of only the last three or four rings of new wood. For use as posts or poles, therefore, trees should preferably not be cut at such an early age or in such small sizes that a considerable portion of the wood is sapwood. By the time the tree is 6 to 8 inches in diameter on the stump it usually has enough heartwood to warrant cutting. Such trees commonly can be grown in about 12 to 15 years where soil and climate are favorable (fig. 16) or in 20 years in less favorable places. Smaller and younger