104 MTCHTGAN ACADE.MV OF SCIKXCE. 



very late in spring compared willi those of most otlier trees. The trunks 

 of our sugar maples as planted for ornament are very often injured by 

 borers, the trees i)robably having been previously damaged by the sun, 

 but trees in the forest or elsewhere so groAvn that the trunks are per- 

 petually shaded during the growing season almost always remain unin- 

 jured. So far as 1 have observed, our trees as they grow naturally in the 

 woods all have their trunks shaded for the whole length by the tops of 

 surrounding trees, or if a seedling gets started in the open and has its 

 own way, limbs near the ground shade the trunk and help keep it sound 

 and help keep out insects. Borers are surest to work in the trunks or 

 large branches of trees that are exposed to the sun when in leaf. In 

 other words, locust trees groAvn among other trees of the same or nearly 

 the same height, are not troubled or but little troubled by borers. This 

 is a broad statement and may have its exceptions. I have not been over 

 all regions of the world where locust trees are grown. 



In some places at the Agricultural College, for example, the trunks 

 of scattering trees have often been badly bored by insects, but trees set 

 in the arboretum, where other trees had already got a start to serve for 

 shade, the borers were very scarce, and the crowded trees shot up straight, 

 and sound and with great rapidity. Sound locust timber has always born 

 a high price in the market, I mean at least for forty years past. In the 

 spring of 1896, in a small open spot in the woods among some young 

 trees, I planted about eighteen sprouts of the common locust usually 

 about the size of a pipe stem or smaller. They are now making a good 

 showing, and where suitably shaded by other trees, have grown straight 

 and nice and are destitute of borers. 



In the spring of 1880, I set in the arboretum a few sprouts of the locust, 

 where other small trees were perhaps ten feet high. In August 13, 1901, 

 with a growth of scarcely 21 years, I measured two of these trees not 

 including the thickness of the bark. The best tree was cut when younger 

 to go to the Paris Exposition. Two of these now standing have a 

 diameter of 



No. 1, at the stump has a diameter of \2Yz inches, 24 feet above ground its diameter is 7 inches. No. 

 at the stump has a diameter of 16 inches, 30 feet above ground its diameter is 8 inches. 



This is a long way ahead of the chestnut at the same age. Well grown 

 locust makes first-class buggy spokes as well as fence posts. 



It is fo be remembered, that locusts will not grow leaves thick 

 enough to shade the ground well and keep out the grass, hence they should 

 be mixed with as many or twice as many box elders, or fast growing 

 evergreens, to furnish shade to push up the locusts, and to keep down 

 grass and weeds. Where locusts are scattered about a few in a place they 

 are less liable to be discovered by borers. Some may like to know, that 

 this locust is not adapted to grow on land in the north of Michigan, 

 known as Jack pine plains, where it has been tried in several counties. 



