FOREST TREES OF THE PACIFIC SLOPE. 425 



Oregon Ash. 

 Fraxinus oregona Nuttall. • 



DISTINGUISHING CHARACTERISTICS. 



Oregon ash, the only timber ash of the Pacific region ; is recognized every- 

 where in its commercial range as one of the most useful hardwoods. Lumber- 

 men call it " Oregon ash," but it is often known simply as " ;ish." 



Forest-grown trees have long, clean trunks and narrow, short crowns of 

 small branches, and are from 60 to 75 feet high and from 1G to 30 inches in 

 diameter; sometimes larger. Trees on the open borders of streams have short 

 trunks and very wide, round-topped crowns with large limbs. In drier parts 

 of its range it is often a crooked tree under 25 feet in height and only from 

 6 to 8 inches through. The trunk bark, rather thick and soft on the surface,, 

 is deeply and regularly furrowed, the wide ridges connected by thinner side 

 ones, and dull gray to grayish brown. Twigs of a season's growth are usually 

 covered with whitish — sometimes brownish — dense, soft, fine woolly hairs, but 

 occasionally are only very minutely hairy or even smooth, with a whitish bloom. 

 Mature leaves (fig. 202), about 6 to 12 inches long, with from 5 to 7 thick, 

 yellow-green leaflets, which are about 3 to 6 inches long by about seven-eighths 

 inch to li inches wide and more or less woolly or downy beneath, as are the 

 grooved leaf stems (fig. 202). Male and female flowers, each borne on separate 

 trees, appear as the leaves begin to come out ; only the female trees bear 

 " seed " (fig. 202), which matures in early autumn in large, full clusters. Seeds 

 vary from about 11 to occasionally 2 inches in length, and the wings from one- 

 fourth to one-third inch wide. Wood, dull yellowish brown with whitish sap- 

 wood. The wood of forest-grown trees is moderately fine-grained and rather 

 brittle, but that of open-grown trees is coarse-grained and elastic — particularly 

 the sapwood of young trees. Of slightly lighter weight than the eastern timber 

 ashes, but in general appearance and quality it compares favorably with them, 

 and is suitable for the same commercial uses for which those timbers are 

 employed. 



Longevity. — Age limits of very large trees have not been determined. Trees 

 from 10 to 25 inches in diameter (grown in the forest) are from 95 to 155 years 

 old. The largest trees appear to grow much more slowly after the first century 

 and probably attain ISO to 250 years before becoming decrepit. 



RANGE. 



From Puget Sound (shores) southward through Washington, Oregon, and California 

 (coast region to San Francisco Bay ; on foothills of Siena Nevada .Mountains to moun- 

 tains of San Bernardino and San Diego counties). Also reported from the southern part 

 of British Columbian coast. 



WASHINGTON. — Western part west of Cascades, but not on Olympic Mountains, from 

 sea level to 2,000 or 3,000 feet. Columbia River, not above The Dalles. Noted at White 

 Salmon on Columbia River in Klickitat County. Seattle. Satsop, Mount Rainer National 

 Forest up to 2,500 feet, especially in the " Big Bottom " of Cowlitz Valley. 



Okegun. — Western part west of Cascades, in valleys. Noted on Willamette River bot- 

 toms near Portland, on Columbia River flats above dunes between McClures and The 

 Dalles (Wasco County), in Cascade (North) National Forest, in Bear Creek, and other 

 valleys of Siskiyou National Forest at about 2,000 feet. 



California. — Noted in Klamath, Mount Shasta. Lassen l'eak, Plumas, and Stanislaus 

 National Forests up to about 2,000 Eeel : in Sacramento River canyon just west of Mount 

 Shasta and at Middle Creek just north of Redding, in Shasta County ; in northern coast 

 ranges west of Sacramento River, near Lewiston, Trinity County, and elsewhere; in 

 Stony Creek National Forest on all tributaries of Eel River; at Cazadero, in Sonoma 

 County, and at Ross Valley, in Marin County, near coast ; in Napa Valley, Napa County, 



