10 
BULLETIN 1437, U. S. DEPARTMENT OF AGRICULTURE 
DURABILITY 
Red alder logs left lying in damp situations will show signs of 
incipient decay within three or four weeks. A shipment of logs used 
at the Forest Products Laboratory for heat-treatment tests showed 
within a short time after they were stored in the yard abundant 
decay from the white rot so common in this wood, and produced 
by the two fungi, Polystictus versicolor and Polystictus hirsutus. 4 " 
The life of alder posts will not exceed two or three years. Table 2 
gives the estimated relative durability of red alder and several other 
species of the Pacific Northwest compared with eastern white oak. 
Table 2. — Durability of red alder compared with other woods under similar 
conditions which permit decay 
Commercial white oak (eastern United States) 
Red alder 
Western red cedar 
Douglas fir (average mill-run) 
Western hemlock 
Sitka spruce 
100 
25- 35 
125-175 
75- 85 
35- 55 
35- 50 
Red alder is reported as being used to some extent for piling in 
salt water, but only in locations where the piling is not subject to 
abrasion. Under such conditions it is said to be relatively free 
from the attack of marine borers which destroy untreated piling 
of most woods. The work of the San Francisco Bay Marine Piling 
Committee includes a test of red alder in that harbor. After nearly 
two years of service alder piles with the bark intact had not been 
attacked by borers, while the wood of those with the bark missing 
was found to be largely destroyed as a result of the ravages of 
lemnoria. Since the bark is easily abraded, this suggests that red 
alder has very little value for marine construction even in protected 
locations. 
SEASONING 
The seasoning of red alder, even lumber of high moisture con- 
tent, does not present any special difficulties. Practically the entire 
cut is kiln-dried and much of it from the green condition, although 
some manufacturers believe that lumber that has been air-seasoned 
for 60 to 90 days before being placed in the kiln gives a stock of 
better quality than that kiln-dried direct from the saw. If the 
stock is partially seasoned, close control of temperature, humidity, 
and air circulation in drying is of less importance than if the stock 
is green at the time it is placed in the kiln. 
Green alder lumber, regardless of the method of seasoning, should 
be piled in such manner as to insure adequate circulation of air 
throughout the entire pile or load. This is accomplished by means 
of foundations not less than 18 inches high at the low point, by keep- 
ing the yard free of weeds, and by means of wide spaces between 
4 Hubert, E. E., Effect of Kiln Drying, Steaming, and Air Seasoning on Certain Fungi 
in Wood. U. S. Dept. Agr. Bui. 1262, 20 pp., illus. 1924, 
