12 
BULLETIN 604, U. S. DEPARTMENT OF AGRICULTURE. 
Table 9. — Results of strength tests on incense cedar and associated species as 
compared icith longleaf pine. 
Species. 1 
Bending. 
Specific 
gravity 
[based 
on 
volume 
when pounds 
green). per 
square 
inch. 
Modulus of 
rupture. 
Per 
cent. 
Modulus of 
elasticitv. 
Maximum 
crushing 
strength (par- 
allel to grain). 
Thou- 
sands 
of 
pounds 
per 
square 
inch. 
Per 
cent. 
Pounds 
per 
square 
inch. 
Per 
cent. 
Longleaf pine 2 (Pinus palustris) 
Douglas fir (Pseudoisuga tarifolia) 
Incense cedar (Libocedrus deeurrens) . . . 
White fir ( Abies concolor) 
Sugar pine (P / n us la m bertia n^ 
Western yellow pine (Pinus ponderosa) . 
0.52S 
.418 
.363 
.350 
.360 
.377 
9.070 
s;2so 
6,040 
5'. 970 
5, 270 
5, ISO 
100.0 
91.4 
66.6 
65.8 
5S.1 
57.1 
1.540 
1,597 
754 
1,131 
966 
1,111 
100.0 
103.7 
4S.9 
73.4 
62.7 
72.1 
4,400 
4.030 
3.030 
2,S00 
2,600 
2,400 
100.0 
91.7 
6S.9 
63.6 
59.1 
55.0 
i Tests made on green specimens 2 by 2 inches and free from all defects. 
2 The data on longleaf pine and Douglas fir are from Forest Service Bulletin Xo. 10S; the data on cedar, 
white fir, sugar pine, and western yellow pine, from Forest Service Circular Xo. 213. 
Tests on strength in relation to moisture, also made on small pieces, 
showed that thoroughly dry sapwood and heartwood are each 2.50 
times as strong as green wood. In these tests the sapwood proved to 
be slightly stronger than the heartwood at all stages of seasoning. 
It was not always possible, however, to take the heart and sap speci- 
mens from immediately adjacent sections of the tree, which might 
explain this slight difference. 
The average shrinkage in cross section in the above tests, in passing 
from the green to the thoroughly dry condition, was 9 per cent for 
the sapwood and 6 per cent for the heartwood. 
DURABILITY. 
Incense cedar is known to be one of the most durable timbers on 
the Pacific slope. The life of a split heart-cedar fence post- is reputed 
to be from 20 to 30 years, and of rails from 30 to 40. and numerous 
instances have been cited where they have lasted longer. Sap-cedar 
posts, on the other hand, are said to last but 5 or 6 years. 
THE TREE. 
GEXERAL DESCRIPTION. 
Incense cedar is one of the most characteristic trees of the California 
forests, its shreddy, deeply furrowed, yellowish-brown or cinnamon 
colored bark, rapidly tapering bole, and dark-green foliage distin- 
guishing it at once. It resembles somewhat eastern arborvita? (the 
white cedar of the north woods) in its flat sprays of scalelike leaves. 
