LONGLEAF PINE. 



11 



Another example may be cited. On a tract logged "clean" in 

 1903, about eight trees per acre were left as culls. They were spike- 

 topped, crooked, and suppressed in growth, and averaged about 8 

 inches in diameter breast high. Within 2 years these trees had started 

 a rapid growth and for the next 12 years increased at the rate of 1 

 inch in every 4 years. The average diameter in 1917 was 12 inches. 

 At the time the trees were left they contained 226 board feet per 

 acre and in 1917 a total of 803 board feet per acre, or three and one- 

 half times their former volume — a gain of 250 per cent in less than 

 15 years. At $5 per thousand feet, 800 board feet would bring $4, a 

 sum sufficient to cover, for the entire period of 15 years, the cost of 

 fire protection at 10 cents per year, reckoned at 5 per cent compound 

 interest, and give a return of 5 per cent compounded on an assessed 

 land value of $2 per acre. Table 2 shows the growth which actually 

 took place on the cull trees during a period of 15 years following 

 logging. 



Table 2. — Actual growth in volume of cull longleaf pine trees, left in logging, 

 during the 15 gears subsequent to lumbering; on loamy sand in the interior 

 coastal plain of central Louisiana. 1 







Volume of trees 



Growth in 15 vears 





(Scribn 



er rule). 



(1902 to 1917). 



Diameter 

 of trees 



















Cbreast 



height) 



1902. 



1902 



1917 



Volume. 



Per cent 



(based on 



volume 



in 1902). 



Inches. 



Board feet. 



Boardfeet. 



Boardfeet. 



Per cent 



7 



10 



80 



70 



700 



8 



20 



95 



75 



375 



9 



32 



104 



82 



256 



10 



45 



134 



89 



197 



11 



62 



157 



95 



153 



12 



83 



186 



103 



124 



13 



110 



223 



113 



103 



14 



142 



26 i 



122 



86 



15 



185 



315 



130 



70 



16 



235 



371 



136 



58 



17 



300 



445 



145 



48 



18 



375 



528 



153 



41 



1 Measurements i>y W. W. Ashe, CI. S. Forest Service. 



GROWTH UNDER FIRE PROTECTION. 



I Qder repeated burning, growth is continually set back and 

 finally most of the saplings arc killed. This lias, for many years, 

 been occurring over practically the entire South (PI. VT). The 

 yearly heighl growth of longleaf-pine saplings from 4 to 12 feet in 

 height fin" -i I;. 6 to 8 feet) was ascertained simultaneously on a 

 tract burned over yearly, and on an adjacent trad which, after 

 having been protected for five years, was accidentally burned in Feb 

 rnary, L917, and afterwards protected. The average yearly growth 

 in height of 100 saplings, on cadi of* the tracts during a period of 



