236 



thrifty trees, as well as old, over-mature standards were found 

 infected. The forest floor is mostly rocks, there being little or 

 no soil cover at all. The chestnut runs about 40 per cent, of 

 the stand, with 25 per cent, rock oak, and the remainder a mix- 

 ture of red, black, and white oak. 



The majority of the infections apparently started in the tops. 

 Some trees had to be climbed to identify the infection. In most 

 cases the characteristic appearance of persistent leaves on 

 girdled branches or on infected sprouts below, large lesions or 

 blisters which have girdled the trunk, were sufficient to remove 

 doubt as to whether the tree had blight. 



It may be said here that in scout work tin; closest observation 

 must be given to all suspicious trees, or trees with danger sig- 

 lials. The most conspicuous danger signals in summer or winter 

 are the persistent dead leaves. In summer, these leaves are 

 light yellow in color, in contrast with the healthy green leaves. 

 As they are killed slowly by a gradual stoppage of sap, they 

 remain rather flattened instead of curling and wrinkling as do 

 leaves killed by frost in the fall. Their color is about the same 

 in summer as that of persistent leaves in winter killed by frost 

 and causes other than the blight. This yellowish shade tinged 

 with a greenisli line like that of haj- in the mow, often lasts long 

 into the Avinter. Generally, though, the persistent leaves in 

 winter a re of a distinctly red rust}^ brown color, curled, twisted, 

 frayed, and blown to shreds on the edges. On an infected or 

 girdled branch, the leaves are persistent. In a healthy limb, 

 when sap action stops in the fall, little corky layers are formed 

 at the base of the leaf stem, and the leaf splits off at this point. 

 In a diseased limb, the sap is held up and the leaf is not cut off 

 by the corky layers. 



With the leaves, small undeveloped nnd unopened burs are 

 often seen. In some instances trees are found with almost every 

 bur remaining, closed and nearly full size. The burs are dark 

 in color and blend with the color of the leaves. If the burs are 

 few in number and scattered, especially if open, the chances of 

 blight being present are small. 



Another characteristic danger signal is the growth of suckers 

 or sprouts in a ring on girdle below a blister or lesion, extend- 

 ing around the tree. The upward flow of the sap being stopped, 



