A NATIONAL PLAN FOB AMERICAN FORESTRY 



861 



types into low-grade, poorly stocked forests. Even the lightest 

 surface fires, if repeated frequently enough, seriously reduce the 

 growth capacity of the forest. In many regions, tree-killing insects 

 and wood-destroying fungus diseases invariably increase as a result 

 of fires. Kegardless of the extent of damage, fires have the effect of 

 depreciating the forest. The extent to which this process has been 

 going on in the United States is indicated in table 4. 



TABLE 4. Average area of forest lands burned annually in the United States, 1926-30 



About 41% million acres annually burned over must be considered 

 as a major contributing cause to the problem of deterioration and 

 devastation, regardless of whether these fires cover cut-over lands, 

 second-growth stands or virgin forests. While the damage as a result 

 of fire may vary from region to region, the ultimate effect is reduced 

 forest values on practically every acre burned over. The process 

 of repeated burning, which is particularly common in the South, 

 demands intensified protection effort against fires if the forests are 

 to be built up to somewhere near their growth capacity. 



EFFECTS OF CUTTING 

 IN EASTERN HARDWOOD STANDS 



Destructive methods of cutting have resulted in decreased value 

 of remaining stands by repeated cullings for the more valuable species, 

 change in composition, and poor stocking of cut-over areas through 

 failure to make provision for reproduction. 



These conditions may be illustrated by the results of private 

 cuttings in the Appalachian hardwood region. The forests of this 

 region are exceedingly complex. About 140 species of trees are 

 native, of which about 60 are important commercially. The kind 

 and quality of products that could be profitably exploited have under- 

 gone a marked change during the comparatively short period since 

 large scale operations began. Forty-five years ago only the walnut, 

 cherry, and the finest of the yellow poplar, northern white pine, 

 basswood, cucumber magnolia, and white oak were worth taking. 

 Commonly only a light culHng of the forest was made. Very few 

 trees were logged that were under 30 inches on the stump, and no 

 logs were taken at the mills that were less than 20 inches in diameter 

 at the small end. Ten years later, the usual cutting limit was 24 

 inches on the stump, and logs 18 inches in diameter could be handled 

 in the mills. By about 1900, the average cutting limit in the woods 

 had dropped to 21 inches on the stump and the average small-end 

 diameter of logs at the mill to 17 inches. By 1905, oak and chestnut 

 trees 15 inches oh the stump and poplar 14 inches or even less were 



