DRY-ROT OF INCENSE CEDAR. 7 
tract was not clear cut, the representation of age, diameter breast 
high, and height classes obtained from the study must not be assumed 
as an exact expression of the actual conditions. 
Each tree was cut as closely as possible to a stump height of 18 
inches, then limbed and bucked. The first or butt log was made 
7 feet long and the others 14 feet long, the number of cuts depending, 
of course, on the length of the tree. The last cut was always made 
well in the top near the upper limit of the heartwood. The reason 
for bucking in 7 and 14 foot lengths was purely a practical one ; any 
sound heartwood could, then be utilized for 7-foot posts. The age 
count at stump height was taken as the age of the tree instead of 
adding a few years corresponding to the height of the stump, since 
the aim is to have all figures taken directly comparable. In this 
case with a minute constant variation no error can be introduced. 
Trees with wounds which destroy the center at stump height were 
avoided when possible, since in such cases an accurate age count 
could not be obtained; hence, trees of this kind are valueless for all 
further calculations in which the exact age is a factor. The sap width 
was obtained from an average of six or eight measurements. Three 
radii were measured to secure the average diameter. Separate 
measurements were made for the area covered by decay. The dates 
of occurrence and. closure, when healed, were determined for all 
wounds present. Each log was split at least once in order to reveal 
completely all decay and internal wounds. Great care had to be 
observed in splitting the logs in order to be certain not to miss any 
decay, since the dry-rot occurs in pockets which may be separated 
in a linear direction by several feet of sound wood. This habit of 
"jumping" also made it exceedingly difficult to trace the entrance 
of the decay in certain cases where the decay might be several feet 
removed from any possible point of entrance. It often became 
necessary to split log after ]og into many small pieces. 
In all, 1,075 trees were analyzed, 509 at Sloat, 266 at Strawberry, 
100 at Cow Creek, and 200 at Crockers Station. 
In all future references in this paper, for the sake of convenience 
the term " intermediate area" will be used to designate the area at 
Sloat, since it represents conditions in the intermediate range, and 
the term "optimum area'' to designate the combined areas at Straw- 
berry, Cow Creek, and Crockers Station, since they represent condi- 
tions in the optimum range. The results of the field work follow. 
SECONDARY ROTS. 
Under this heading are grouped all decays the causes of which 
are unknown. Such decays are of various types and are almost 
invariably found immediately adjacent to open or healed-over 
wounds, particularly fire scars. Instances were encountered where 
