22 BULLETIN 680, U. S. DEPARTMENT OF AGRICULTURE. 



scientific name applied to Douglas fir is "Abies taxifolia Poiret," 

 published in 1804, on which the present acceptable name, Pseudot- 

 suga taxifolia (Poir.) Britton 33 , is based. From 1833 to 1889, the 

 date on which the latter name was established, Douglas fir was 

 known to many botanists as "Abies Douglasii Lindl.," and from 

 1867 to 1889, as "Pseudotsuga Douglasii, Carriere." 



Some 22 different garden varieties of Douglas fir have been named, 

 most of which are distinguished by the size, form of crown, color 

 and shape of leaves, and habit of the branches. 34 



DISTINGUISHING CHARACTERISTICS. 



Excepting the great sequoias of California, Douglas fir is the 

 most gigantic tree of our western forests. Under the best con- 

 ditions for growth, which exist chiefly in the northwest Pacific 

 coast country, it ordinarily reaches 180 or r*)0 feet in height and from 

 34 to 6 feet in diameter. Exceptionally large trees occasionally found 

 are from 200 to 330 feet high and from 8 to 10 feet in diameter. 35 Under 

 less favorable conditions, such as prevail in the range of Douglas 

 fir outside of the humid Pacific coast region (Map No. 6), it com- 

 monly attains a height of from 75 to 125 feet and a diameter of 

 from 24 to 40 inches, while in high, exposed situations it is much 

 smaller or greatly stunted, sometimes under 3 feet in height. 



The typical crown form of young trees is an open, broad, sharp- 

 pointed pyramid; the lower branches are straight or somewhat 



by a number of German authorities. Others, however, recommend using the Rocky Mountain form 

 because of its greater hardiness. 



The first introduction of Douglas fir in eastern United States dates from 1863, when Dr. C. C Parry 

 is said to have sent seeds of the Rocky Mountain form to the botanic garden of Harvard College. Trees 

 raised from this seed grew thriftily and have proved well adapted to the climate of New England. Later 

 numerous plantings of Douglas fir from its Rocky Mountain range have established the perfect adapt- 

 ability of the species to our Northeastern States, specimens of it growing fairly well even as far south as the 

 District of Columbia. Douglas fir from the moist climate of its Pacific range does not, as a rule, grow 

 well in our Eastern States. 



A number of writers on American trees have maintained that the Pacific slope and the Rocky Mountain 

 forms of this tree are distinct species, this view being based on the common occurrence in the Rockies of 

 blue-leafed trees with the bracts of the cones often reflexed, and of green-leafed trees in the Pacific region 

 with the bracts of the cones usually straight. The decidedly more thrifty growth in Europe and in 

 eastern United States of the Rocky Mountain form, as compared with that of the Pacific slope tree also 

 seemed to indicate specific distinction between these two regional forms. Broadly considered, however, 

 the trees of these regions can not be maintained as distinct species, for the characteristics offered to dis- 

 tinguish them are not dependable, the real difference between them appearing to be wholly of a silvical 

 nature. 



33 Several authors maintain for this tree the name Pseud otsuga mucronata (Raf.) Sudworth, which the 

 writer believes to be lawfully antedated by P. taxifolia (Poir.) Britt. Eor a full discussion of the basis 

 of this decision, see Bull. 17, Div. For., 23, 1898. 



3 4 The most distinct and best known of these forms is P. taxifolia pendula (Engelm.) Sudw. and P. 

 taxifolia glauca (Beissn.) Sudw. (Other varieties are listed in Bulletin 17 of the Forest Service, "Check 

 List of the Forest Trees of the United States," 24, 1898, and described by Beissner in his Handbuch der 

 Nadelholz-Kunde, ed. 2, 106, 1909). 



35 In a letter dated Nov. 26, 1912, Mr. Bartle F. Harvey of 265$ Fifth street, Portland, Oreg., called 

 the writer's attention to a Douglas fir tree 14 feet in diameter and 200 feet high, this tree being located 

 about 175 feet from the Tacoma & Eastern Railroad at a point about 2 miles south of the town of Min- 

 eral, Pierce County, Wash. The tree is on the tourists' route to Mount Rainier and is visited annu- 

 ally by many people. 



