DRY-ROT OF INCENSE CEDAR. 



31 



the work of the dry-rot fungus. The reader should remember that 

 the percentage of cull based on the merchantable volume of the trees 

 would be higher than the percentages here given, since these are based 

 on the total volume of the trees outside bark and including the entire 

 top. In the younger age classes up to 160 years the percentage of cull 

 is small and variable, in one class higher in the suppressed, in another 

 higher in the dominant, and in a third equal. But in the age class of 

 161 to 200 years a decided jump in the percentage of cull occurs, 

 particularly in the suppressed trees. While the increase in the case of 

 the dominants is only 3 per cent, in the suppressed trees it amounts to 

 8 per cent, bringing the cull percentage to 12. In the next age class 

 a still further change is apparent. Here the cull percentage in the 

 dominant trees increases strongly, as does also the percentage in the 

 suppressed trees, the latter still remaining considerably higher than 

 the former. But in those subsequent classes which have a sufficient 

 numbers of trees to make the data of value, the cull is higher in the 

 dominant than in the suppressed trees. When the age classes are 

 combined, the total cull is 4 per cent more in the suppressed than in 

 the dominant trees. 



The salient features shown by Table II are the low percentage of 

 cull in the younger age classes, the sudden increase earlier in the 

 suppressed than in the dominant trees, which after it once begins goes 

 steadily on with advancing age, and the higher percentage of cull in 

 the suppressed trees as compared with the dominant trees in the two 

 age classes which show the first sudden increase in this percentage. 



However, the percentage of cull caused by dry-rot is not the only 

 figure of interest, since it is prerequisite that the trees first be infected 

 and that these infections develop sufficiently to cause measurable 

 cull. Table III gives the figures on percentage of infection and cull 

 cases. The number of trees used as the basis and the average age 

 are the same as in Table II. 



Table III. — Infections and cull cases found in incense cedars of the combined areas. 



to 40 years .... 



41 to 80 years 



81 to 120 years... 

 121 to 160 years.. 

 161 to 200 years.. 

 201 to 240 years.. 

 241 to 280 years . . 

 281 to 320 years.. 

 321 to 360 years.. 

 361 to 400 years.. 

 401 to 440 years.. 



Combined. 



Aee class. 



Infections (percentage 

 of total number of 

 trees). 



Dominant. Suppressed, 



12 



50 



62 



57 



71 



87 



100 



100 



100 





 5 

 33 

 42 

 62 

 74 

 82 

 90 

 87 

 100 

 100 



Infections causing meas- 

 urable decay (percent- 

 age of t otal cull cases) . 



Dominant. Suppressed. 



100 

 100 







5 

 15 

 28 

 44 

 63 

 78 

 88 

 87 

 100 

 100 



