Logging Longleaf Pine. 393 



TABLE V. 



Growth in Board Foot Contents, Doyle Rule, in Twenty Years — 

 Longleaf Pine in Tyler County, Texas. 



Present Present volume, Growth in years, Growth, per cent., 

 diameter. board feet. board feet. twenty years. 



12 75 65 87 



13 95 80 84 

 H 130 95 73 



15 167 108 65 



16 220 117 54 



17 280 125 45 



18 325 132 40 



19 375 138 37 



20 465 143 3i 



21 530 146 28 



22 600 148 25 



23 670 150 22 



24 760 151 20 



25 845 153 18 



26 940 154 16 



27 1,040 155 15 



28 1,150 154 13 



29 1,260 152 12 



The volumes in board feet, Doyle rule, of trees of all sizes were 

 prepared by measuring about 400 felled trees. By using the 

 average merchantable heights, assuming that a tree of one diam- 

 eter will grow to the height of the average tree in the upper 

 diameter class, the growth per tree as taken from the volume 

 table was as recorded in Table V. 



On the eighty acres upon which the growth was measured it 

 was found that 690 trees now below the limit of 12 inches would 

 become merchantable in twenty years. Their volume added to 

 the growth on the present stand gives the total second crop. 



TABLE VI. 



Growth Per Acre op Longleae Pine in Twenty Years After Removing 

 First Cut — Tyler County, Texas. 



Original stand, board feet, 7,690 



First cut, board feet, 5,990 



Stand left, board feet, 1,700 



Growth in twenty years, board feet, 957 



Trees maturing, per acre, 86 



Volumes of same in twenty years, board feet, .... 743 



Total growth, board feet, 1,700 



Final volume, board feet, 3,400 



This gives an increase of 100 per cent, for twenty years, of 



