bustible material. Perfectly healthy trees nay pass through 

 a moderately hot fire with only a scorching of the bark. Act'i 

 al estimates covering considerable areas have placed the annn, ! 

 loss from insect infestations in sugar and yellow pine in Dis- 

 trict 5 at ^50,000. We now feel quite sure that this estimate 

 is conservative. Addei? to this Garage is loss of increment 

 in trees in.jxired but not killed, and the injur3r to the geneirl 

 health of the forest through the unbalancing of forest condi- 

 tions. 



INFESTATIONS, 

 Classes of Infestations. 



Infestations may be either what v/e raay call normal, 

 that is an occasional tree killed here and there, or epi- 

 demic, where a large percentage ol the trees are hilled in a 

 certain locality. 

 Normal . 



This term will apply to areas having not over 1C in- 

 fested trees to the section, or to small groups of infe. i- 

 ed trees of infrequent occurrence, particularly where the 

 killing is steady and does not increase from year to yerr- 

 Epidemic , 



Where normal infestations increase rapidly or 

 where a large percentage of the trees become suddenly 

 infested with tree-killing insects, the infestation 

 may be considered epidemic. 



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