34 



BULLETIN 244, U. S. DEPARTMENT OF AGRICULTURE. 



in basal area at breast height was 75.4 per cent, the largest 311 per 

 cent, and the average for 7 representative trees was 171.4 per cent 

 over their former rates of growth. The trees ranged from 45 to 101 

 years old at the time of the logging, but most of them were between 

 60 and 70 years. Since height growth was mainly complete at this 

 age, it is perfectly safe to say that the volume increment of the trees 

 took place at approximately the same or possibly at a somewhat 

 greater rate, because of the greater increase in the size of the upper 

 part of the stem at this age. 



Table 13. — Comparative growth of shortleaf in Jive-year periods before and after logging. l 





Tree No. 



Age at 

 time of 

 logging. 



Increase in basal area (breast height). 





Five-year periods prior to logging. 



Five- 

 year 

 period 

 after 

 logging. 

 1908-1912. 



Rate of 

 increase 





1883-1887 



1888-1892 



1893-1897 



1898-1902 



1903-1907 



since 

 logging 

 over pre- 

 vious 

 five-year 

 periods. 



1 



45 

 57 

 65 

 65 

 69 

 69 

 101 



Sq. in. 

 4.2 

 2.0 

 4.6 

 1.7 

 4.5 

 3.2 

 5.8 



Sq. in. 

 4.9 

 6.2 

 7.2 

 3.6 

 9.5 

 10.1 

 6.0 



Sq. in. 

 5.6 



13.0 

 7.8 

 3.9 



10.5 

 8.2 

 6.3 



Sq. in. 

 . 6.5 

 8.1 

 5.6 

 6.3 

 8.6 

 11.8 

 6.5 



Sq. in. 

 8.2 

 6.8 

 8.8 

 6.9 

 6.0 

 12.8 

 6.8 



Sq. in. 

 14.4 

 12.4 

 15.8 

 24.0 

 16.1 

 52.7 

 18.0 



Per cent. 



2 



83.0 



3... 



80.3 



4 



247.9 





166.6 



6 



311.2 



7.. 



165.9 





Average 







67 



3.7 



6.8 



7.9 



7.6 



8.0 



21.9 



171.4 



1 Typical shortleaf stand cut 5 years ago to an approximate diameter limit of 14 inches in average quality 

 site in western Arkansas. 



CAUSES OF INJURY. 



The damage to forest growth caused by fire far exceeds the com- 

 bined effect of all other injurious agencies. At the same time, this 

 cause of injury is the most susceptible to control of man. The annual 

 burning of the forest floor, extensively practiced in the past through- 

 out the shortleaf region, has been done with little realization of the 

 damage to the forest. Shortleaf which has passed the earlier stages 

 suffers much permanent injury from fire. Abundant seeding, low resin 

 content of the wood, and early rapid height growth, in addition to 

 sprouting, afford shortleaf perhaps the best chance of any of the im- 

 portant southern pines to survive under adverse conditions caused by 

 fire, but in spite of these favorable characteristics much loss and injury 

 occur. 



Completely stocked stands of shortleaf over 20 years in age are 

 rarely found in tracts of considerable size, except in old fields and in 

 other situations where fire has been practically excluded. As a rule, 

 the stand is irregular in density, with many small openings, for which 



