560 THE POPULAR SCIENCE MONTHLY 



northern and has actually crossed it in its southern section. West of the ridge in 

 most of the regions where chestnut is wanting, its disappearance has been quits 

 recent and, indeed, it is still disappearing. 



This strange phenomenon is not confined to North Carolina, but is to be seen 

 to a greater or less extent on the outer portions of the range of the chestnut, 

 throughout the southern half of its range. Reports show that chestnut has 

 largely died out or was formerly much more abundant in portions of Virginia, 

 South Carolina, Georgia, Alabama, Mississippi and Tennessee, and that the 

 recession is still going on. 



This apparently mysterious decline in vigor of the chestnut in the 

 south is evidently not due to any one factor, but probably to a variety of 

 causes. Probably frequent forest fires are to blame for the beginning of 

 most of the trouble, and these, as we have seen, are followed by the 

 attacks of fungi and insects. The cutting over and clearing up of large 

 areas may also result in soil conditions which arc not as favorable as 

 formerly. Climatic changes may also have something to do with the c;ise. 



If we summarize briefly the troubles of the chestnut described in the 

 preceding pages, we find that in the northern half of its range it is a 

 prey to the bark disease ; throughout its whole area it is attacked by the 

 two-lined chestnut borer, as well as by other insects, and also by fungi 

 which destroy the heartwood. The common practise of coppicing can 

 only be regarded as harmful when carried on for several generations. 

 Forest fires have been frequent, resulting in injuries of many sorts. In 

 the southern states still other factors are evidently at work. 



Let us now turn to the other side of the balance sheet, i. e., to the 

 assets of the chestnut, those traits in its life and habits which are of ad- 

 vantage to it in the struggle for existence and the perpetuation of the 

 species. 



Of first importance is its rapid and vigorous growth. Among the 

 numerous advantages to be derived from this is the power to close over 

 any chance wounds with new tissue with greater ease than would be the 

 case in a more slowly growing species. And we have already seen how 

 wounds may open the door to disease and decay. 



An inherent powder for rapid growth also enables the tree to develop 

 roots quickly in times of need, and also, in competition with other species 

 in the forest, to lift its crown above them in order to secure better light. 

 Moreover, in this connection we should recall that the chestnut is fairly 

 "tolerant," i. e., not easily killed out or injured by the shade of older, 

 larger trees. 



As regards its soil requirements, we find that, unlike such trees as the 

 tulip or basswood, it is not at all fastidious. Its principal needs seem to 

 be an adequate amount of moisture in the soil, for it appears to be quite 

 sensitive to drought, and also a soil which is fairly deep and loose. As 

 to the chemical nature of the soil it is not particular, except that it rarely 

 grows in a limestone region. Xeither need the soil be a fertile one, for 

 chestnut trees grow and thrive on sterile soils, provided they be porous 



