556 THE POPULAR SCIENCE MONTHLY 



advance in the area in which the chestnut naturally occurs. However, 

 we shall consider this point again later. 



In common with other forest trees, the chestnut is subject to the 

 attack of several species of fungi which bring about a decay of the heart 

 wood. Normally, the tree is protected from such invaders by its incase- 

 ment of bark, but when this is injured in any way, a vulnerable spot is 

 opened up through which fungi can enter. Notably is this the case in 

 trees injured by forest fires, for here the living bark as well as the sap- 

 wood underneath may be entirely killed in spots, causing the so-called 

 fire-scars, and furnishing an easy ingress for fungi. Once inside, in the 

 heartwood, the fungus may work up and down in the interior of the 

 trunk, softening the wood by its decaying action, or "dozing" it, as the 

 lumbermen say. If the tree, thus deprived of the firmness of its solid 

 cylinder of heartwood, its chief mechanical support, does not fall a prey 

 to the next violent windstorm, it is in any case weakened, and the way 

 lies open for attack upon its last stronghold, the sapwood and living 

 bark. 



Another widespread trouble of the chestnut, which I have found of 

 common occurrence in New England forests, but apparently more de- 

 structive in the southern Appalachian mountains, is caused by the attack 

 of the two-lined chestnut borer, Agrilus bilineatus. Next to the fungus 

 which causes the bark disease, this insect is perhaps its most serious 

 enemy. It is said to have a preference for trees enfeebled in some way, 

 through such causes as drought, unfavorable soil conditions, etc., yet it is 

 possible that where it breeds in great numbers it may be forced to attack 

 vigorous individuals. In any case I have seen many examples of trees, 

 which to all appearances had been in a perfectly sound condition, being 

 rapidly killed by the attacks of this tiny grub. On opening up the inner 

 bark, the long, sinuous channels of the larvae were disclosed, now and 

 then with a sharp turn in a lateral direction, the combined effects of 

 several of these galleries resulting in a practical girdling of the tree. 

 Many other insects attack the chestnut, but they are of secondary im- 

 portance. 



Let us next consider the practise of " coppicing." As is the case with 

 many other of our forest trees, the chestnut habitually sends up sprouts 

 from the stumps of felled trees, sometimes more than one hundred of 

 these developing from a single parent stump. These "coppice" shoots 

 grow rapidly, having the well-developed roots of the parent tree at their 

 disposal for the absorption of nourishment from the soil, and enter into 

 fierce competition with one another for light and space. Although in the 

 natural course of events the weaker ones succumb and die out in the 

 struggle, the woodsman may assist nature in this process of elimination 

 by cutting out the weaker shoots early, in order to give the more vigorous 

 ones a better chance In either case, eventually four or five, or rarely 



