COMMERCIAL USES OF DOUGLAS FIR 



71 



Some species, as an example, redwood, are character- 

 ized by the immense size of individual trees, but Douglas 

 tir is marked also because of the large average size of 

 the trees and the density of tree growth per unit area. 

 ( )fttimes one can find the trees growing so closely to- 

 gether that a considerable distance can be traversed 

 tbriiugh which one is able to have his hand placed on a 

 tree for every step of the way. 



PROPERTIES OE THE WOOD 



L'nited States Forest Service Bulletin ]ii,s shows 

 that Douglas fir is the strongest wood for its weight 

 of any wood found in the United States, and that it ranks 

 near the top in strength value among all woods. This 

 bulletin shows it to have an average breaking strength 

 of O.GO.j pounds per square inch in green stringers and 

 7,142 pounds in air-seasoned ones. Its green weight is 

 3.300 pounds per 1,000 feet board measure. Its great 

 strength, combined with its lightness, makes it an ideal 

 structural wood. Its practically inexhaustible supj.ily, 

 the decreasing areas of other go<id structural woods and 

 their comparatively small supply, mean that Douglas fir 

 will, before many decades, become the most common 

 and most used of all our American woods. 



Because of the immense size of the timber, a Douglas 

 fir log will produce a very high percentage of perfect 

 timber, free from knots and other defects common t(_> 

 species of smaller growth. 



Douglas fir offers a marked contrast between its 

 spring and summer rings of growth. This characteris- 

 tic gives the wood an extraordinarily pleasing grain, 

 or figure, when cut at certain angles to the log. The 

 greatly admired beauty of hardwoods, especially the oak 

 in its quartered faces, is obtained by cutting the boards 

 parallel with the radial planes of the log. This is due to 

 exposing the greatest possible area of the medullary 



A LARGE AIR-DRYING YARD OK DOUGEAS FIR 



Air drying reduces the amount of moisture and simultaneously increases the strength. 

 The large mill in the background cuts over 400,000 feet of lumber every work- 

 ing day. This particular sawmill is said to be "the last word" in efficiency. 



THE TWO VETERANS 



The butt end of a Douglas fir log some thirteen feet in diameter and one 

 of the old lumbermen who has spent most of his life in the Pacific 

 Coast lumber industry. 



rays. Douglas fir, as all conifers, has very small 

 medullary rays, so one must not look to this 

 characteristic for its beauty. To obtain the most 

 pleasing grain in this wood, the rings of growth 

 must be cut across at a very small angle. This is 

 done by rotating the log after a softening bath in 

 steam against a sharp knife, and a thin section of 

 the wood is laid out on a table in one immense 

 sheet. In rotating the log against the knife the 

 rings of growth are cut across nearly parallel, 

 thus exposing large, irregular areas of the hard 

 and soft, or dark and light, rings, creating 

 nnriads of irregular designs. One with a fair 

 imagination can make out contours of almost 

 any object he might desire. 



In point of durability Douglas fir ranks well, 

 and when used in construction intelligently, en- 

 abling sufficient and proper ventilation, will last 

 several generations. 



