DISEASES OF THE CHESTNUT AND OTHER TREES 81 



It is difficult to see how such sprouting, particularly when it is 

 repeated for several years, can be from injured roots. If the trees 

 killed by the bark disease have first been weakened by winter 

 injury or drought, it would appear that only the parts above ground 

 were affected. 



(5) On Long Island, for example, the following varieties of trees 

 are commonly found in good condition, although growing side by 

 side with dead chestnuts. Most of these have a more southern 

 range than the chestnut or are exotic. All of them suffered in the 

 cold winter of 1903-4, but they are now in good average condition, 

 whereas there are few healthy chestnuts left on Long Island, and 

 the great majority are dead. The trees referred to are such species 

 as the persimmon, sweet gum, tulip tree, black jack oak, pin oak, 

 pecan, Paulownia tomentosa, and several magnolias. 



(6) The location of lesions on the tree-trunks or large branches 

 bears, over the whole range of the disease, no constant relation 

 either to exposure or to the points of the compass. Their orienta- 

 tion seems to be determined entirely by the location of the injury 

 through which inoculation took place, which is very commonly a 

 borer's tunnel. 



(7) It is not necessary to assume any predisposing environmental 

 effect on the host, since the disease kills vigorous growing trees of 

 all ages that do not show the slightest signs of any sort of injury, 

 either in appearance or increment. Young vigorous trees grown 

 from imported seed under greenhouse conditions, and hence free 

 from any possibility of winter or drought injury, have succumbed 

 immediately to inoculation. In other words, the fungus alone is a 

 sufficient cause. 



Various theories have been advanced which have assumed weak- 

 ness on the part of the chestnut due to coppicing. Whether coppic- 

 ing weakens the tree or not is an open question. Coppice is perhaps 

 particularly subject to infection from wood rotting fungi which 

 consume the stump. Other species of trees, such as the oaks of 

 England, appear to have been coppiced for centuries without any 

 perceptible change of vigor; and in this connection, one cannot 

 help thinking of the treatment that has been accorded to the 

 mulberry, willow, and Lombardy poplar in Italy from antiquity, 

 without any change in vigor so far as known. However, any 



