GENERAL CONDITIONS 



55 



amount of good done in " improving " the grass and killing 

 snakes is offset many times by the loss in soil fertility, small 

 trees and mature timber. Furthermore, in addition to these 

 direct losses a large amount of indirect damage can be charged to 

 burning because it makes the trees more susceptible to fungus and 

 insect attack. 



Annually the red rot fungus — Trametes pini — causes 

 thousands of dollars' worth of damage to living trees. Special 

 care should be taken to see that a tract of timber is not infested 

 with it because it works rapidly and thoroughly. 



Another common result of unrestricted burning is a serious 

 infestation of pine bark beetles — Dendroctonus pinicola. This 

 insect, if unchecked, is capable of kilKng large amounts of other- 

 wise healthy timber as numerous areas in the southeast show. 



Other forms of damage are not serious. Snow-break does not 

 occur in the warm climate of the pine belt nor does lightning 

 damage more than an occasional tree. Hurricanes may snap 

 off all the large trees in their path but fortunately they seldom 

 cover large areas. 



Stands per acre under virgin conditions, which nearly always 

 means pure stands of longleaf pine, range from 20,000 board feet 

 to 5000 board feet with 10,000 board feet as a high average for 

 large tracts. ' Second growth stands vary in volume directly with 

 the age so that their possibilities may best be obtained from the 

 following growth figures. Yields per acre in cubic feet may be 

 converted into board feet by multiplying by seven. 



OPTIMUM GROWTH 



