DRY-ROT OF INCENSE CEDAR. 3 



sumption is based on the factors of increment and decay, of which 

 almost nothing is known. When deterioration is used in place of 

 decay, it is an impossibility to reach a conclusion as to just what 

 factors of loss are included in the term. 



The term "total loss" has been introduced byMeinecke (16, p. 4-5) 

 to cover all factors which lead to any reduction of increment or 

 actual volume in a stand, and he makes a strong plea for exact studies 

 of all components of the total-loss factor for individual species before 

 any effort is made to determine this for the mixed stand. 



To determine the components of the total-loss factor for any given 

 species is merely a matter of simple observation, but to gauge accu- 

 rately their relative importance is not easy, calling for careful com- 

 prehensive work. 



In the case of incense cedar the numerical dropping out of indi- 

 vidual trees, the mechanical injuries caused by fire, frost, light- 

 ning, the breaking of branches, and other causes, a mistletoe, and 

 several fungi play a more or less important part in the total-loss 

 factor. These components may be divided into two broad classes, 

 those reducing the future capital of timber (lessening the increment) 

 and those reducing the present capital of timber (destroying actual 

 merchantable material). It is impossible to draw a sharp line 

 between these two classes, since some components find a place in 

 both. 



The unavoidable yearly dropping out of certain trees, varying in 

 size from seedlings to veterans, affects both the increment and mer- 

 chantable material in a stand. Mechanical injuries, while primarily 

 causing a loss in the merchantable timber, to some extent interfere 

 with the normal growth of the tree, thus reducing the increment. 



A mistletoe (Phoradendron juniperinum libocedri), the incense-cedar 

 rust (Gymnosporangium blasdaleanum) (15, p. 35-37; 11), a leaf-in- 

 habiting fungus (Stigmatea sequoiae) (3, p. 87; 4, p. 314), and the black 

 cobweb fungus (Herpotrichia nigra) all primarily cause a loss in the 

 future capital of timber by reducing the annual increment of infected 

 trees. The amount of this loss is exceedingly difficult to gauge 

 accurately, but it is so small in relation to the damage caused by 

 the agencies reducing the present capital of timber that the above- 

 mentioned organisms are given no consideration in this paper except 

 incidental mention. Under certain conditions, the mistletoe is 

 responsible for a slight reduction in the merchantable contents of 

 the host tree by causing spindle to barrel shaped swellings on the 

 boles of mature and overmature trees (14, p. 37). The wood of 

 these swellings is rendered valueless for lumber, owing to the pres- 

 ence of the mistletoe "sinkers," or roots, either living or dead. 

 Swellings are rarely, if ever, found on the boles of younger trees. 



