DEY-EOT OF INCENSE CEDAR. 35 
Table V. — Combined data relating to dry-rot found in incense cedars of the combined areas. 
Age class. 
Average 
age 
(years). 
Number 
of trees 
(basis). 
Percentage of— 
Dry-rot 
volume. 
Severe 
cull 
cases. 
Cull 
cases. 
Infec- 
tions. 
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 
40 
60 
105 
111 
180 
223 
259 
296 
334 
370 
436 
1 
51 
185 
284 
233 
118 
94 
49 
19 
4 
2 

4 
20 
29 
42 
61 
79 
88 
90 
100 
100 
92 
100 
100 
1,040 
42 
56 
Table V strikingly demonstrates the cumulative risk to incense 
cedar from dry-rot with advancing age. Starting at 1 per cent of 
cull in the age class of 41 to 80 years it mounts to 67 per cent in 
the class of 321 to 360 years. With a very gradual increase up to 
160 years it then becomes rapid. The figure of 82 per cent in the 
class of 361 to 400 years, even though on an insignificant basis, is 
not without significance when considered in relation to the general 
previous progression. That this figure should drop to 5 per cent in 
the last age class need not cause concern, since the basis is only two 
trees. Even though infected, a tree may escape extensive decay 
throughout its life. This is a rare occurrence, however. The percent- 
age of severe cull cases closely follows the percentage of cull throughout 
until the last two age classes with their small bases are reached. 
These two sets of figures show beyond doubt the high percentage of 
loss through dry-rot that may be expected in overmature cedars and 
clearly prove that the presence of such trees in our stands of the pres- 
ent and the future can be nothing but an economic loss. 
That the percentages of cull cases and of infections do not follow 
the same form as the two others just discussed was shown in previous 
tables, but is more clearly brought out here. The reasons for this 
have been touched upon. However, these two figures are of interest 
when compared. It is seen that with advancing age the percentage 
of cull cases becomes increasingly higher at a more rapid rate than 
does the percentage of infections, until finally in the class of 321 to 
360 years the two coincide. To be more explicit, the infections 
gradually begin to cause more and more measurable decay, until 
finally every infection has resulted in a cull case, no matter how slight. 
In the last two age classes both cull cases and infections have reached 
100 per cent; but again we are confronted by the small basis and this 
figure can, not be accepted. There is no doubt that a tree by rare 
chance may escape infection throughout its life, but there is hardly 
