DRY-ROT OF INCENSE CEDAR. 49 



through dead or broken tops are so insignificant that they may be 

 entirely disregarded. (4) Severe wounding is not a prerequisite for 

 severe cull cases or extensive decay at any stage in the life of incense 

 cedar. 



APPLICATION OF RESULTS. 



RELATIVE IMPORTANCE OF DRY-ROT. 



In the foregoing discussion the one big factor which stands out 

 almost to the exclusion of all others is the dry-rot. Mechanical 

 injuries of certain types play some r61e, not only in destroying 

 merchantable timber values but in lessening the annual increment. 

 However, it is chiefly the fact that wounds are the means for the 

 entrance of dry-rot which makes them of any but insignificant 

 importance. 



Factors reducing the annual increment of the host, namely, Gym- 

 nosporangium hlasdaleanum, PTioradendron juniperinum libocedri, Stig- 

 matea sequoiae, and Herpotrichia nigra are of minor importance. In 

 fact, only the first two named, being decidedly ubiquitous, are 

 worthy of the least consideration; but the resulting loss is so slight 

 and intangible that under present conditions it may well be disre- 

 garded except incidentally. The rare trifling logs in merchantable 

 timber from burls of the mistletoe can not be of consequence. 



Fungi such as Polystictus abietinus, P. versicolor, Polyporus volva- 

 tus, and others (see p. 4), only attacking dead wood and never 

 found on living trees, are to be regarded as beneficial, since they 

 hasten the decomposition of ground litter, thus increasing the humus 

 in the soil and removing a serious fire menace. 



Loss resulting in the heartwood of living trees from the so-called 

 secondary rots is very slight in the aggregate. It is rare that such 

 decays are at all far-reaching, and, furthermore, it is possible that 

 certain of them may be abnormal forms of the dry-rot. 



To repeat, then, the one big consideration from a pathological 

 viewpoint which must hold above all in the silvicultural treatment 

 and utilization of incense cedar is the dry-rot, together with the 

 interrelated mechanical injuries. 



CONTROL OF DRY-ROT. 



Very little can be hoped for in the line of any serious consideration 

 or attempt at direct control of dry-rot on private holdings for years 

 to come. The private owner is averse to any increase in expenditures 

 which does not show prospects of immediate gain. On certain private 

 holdings where the incense cedar was heavily affected by dry-rot, all 

 the trees have been left standing, only the more valuable species 

 being removed, leaving the diseased individuals to continue spreading 

 the decay to uninfected members of the present and future genera- 

 tions. 



