12 



BULLETIN 1061, U. S. DEPARTMENT OF AGRICULTURE. 



two seasons before and two after the burnings, furnishes good evi- 

 dence of the effect of protection. (See Table 3.) 



Because of the stimulus of increased light and soil 

 moisture, a tree measuring 10.4 inches in diameter 

 at the time of logging grew during the next 18 years 

 to a diameter of 18.2 inches, an average of nearly 1 

 inch in 2 years. The merchantable length increased 

 from 48 to 56 feet; the merchantable volume from 

 100 to 326 board feet, an average yearly increase of 

 13 per cent and a total increase of 226 per cent. 

 The butt log, which at the time of logging would 

 have furnished a 4 by 4 stick, now yielded a 10 by 10 

 timber. The value of the standing tree at $1 per 

 thousand was 10 cents when it was left in logging, 

 and in 1920 at $8 per thousand it was $2.60. The 

 value of the lumber product of the tree increased 

 from $1.70 to $14.75. 



Table 3. — Growth in height of longleaf trees from // to 12 feet in height, on 

 lands burned yearly and on protected lands. (Berkeley County, S. C.) 



Year. 



Yearly growth in height. 



On land 

 burned 



over 

 yearly. 



On pro- 

 tected 

 or "rough" 

 land 

 (except 

 burned in 

 February). 



Growth on 



burned 



land 



on basis of 



that on 



unburned 



land. 



1915 



Inches. 

 11.8 

 12.9 

 15.0 

 12.3 



Inches. 

 19.6 

 22.1 

 10.2 

 18.1 



Per cent. 



60 



58 



147 



68 



1916 



19171 



1918 



TotaP 



52.0 



70.0 



3 74 



1 Fire in February. 



2 Four years. 



3 Average. 



Thus the two-year average growth of longleaf pine for 1915 and 

 1916, on the land regularly burned over, was 12.4 inches as com- 

 pared with 20.3 inches on the unburned land, or a growth on the 

 burned land of only 61 per cent of normal. 



Following the accidental fire on the protected land, the growth 

 the following season averaged only 10.2 inches, or about one-half 

 the usual amount under protection; and the following or second 



