16 WOODLOT FORESTRY. 



Specimen G is from, a sassafras, and, a good sample of the 

 class of inferior trees which are allowed to remain in the forest. 

 Specimen A was 12 inches in diameter when this tree was not 

 quite 4 inches. During the last ten years this tree was scarcely 

 able to maintain life. It is a weed tree, and has no place in a 

 timber forest. 



This discussion and the illustrations show some of the possi- 

 bilities of tree growth. They give an insight into tree history, 

 and indicate the effects which trees have upon one another as they 

 grow together in a forest. Anyone can. take Fig. 8 into a forest 

 which is being cut, and there read life histories comparable at 

 every point with those shown here. Of course, any complete 

 study of tree growth would include an analysis of heights as 

 well as of diameters, but that may be ignored here, for the sake 

 of simplicity, as well as because the relation between height and 

 diameter is fairly constant in any given stand or forest unit. 



A COMPARISON OP ACTUAL AND POSSIBLE YIELD. 



The diagrams on the opposite page, Fig. 9, show at a glance 

 the value of proper thinnings. The relative size of these dia- 

 grams was determined by a study of the average volume growth 

 of the unthinned stand, and the maximum volume growth of the 

 theoretical thinned stand, as shown on individual trees which 

 grew under conditions which would normally be found in thin- 

 ned stands. The unthinned stand at forty years of age showed 

 a total product of 2,240 cubic feet per acre, in comparison with 

 a possible 31,296 cubic feet per acre in a properly thinned stand. 

 While these figures represent the difference in volume, they do 

 not represent the difference in value. It is quite probable that 

 the 1,808 cubic feet left after the forty-year cut in the properly 

 thinned stand would have double the value, foot for foot, of 

 that which now remains in the forest which was not thinned 

 until it was forty years old. This fact becomes more evident 

 when it is realized that the volume of the improved stand thus 

 represented would be largely saw timber instead of fuel. 



