84 FOREST TREES OF THE PACIFIC SLOPE. 



changes of temperature, gradual ; summers generally mild and winters not severe. Nev- . 

 ertheless, average daily, monthly, and yearly temperatures and average annual precipita- 

 tion and humidity vary greatly from southern limits of range in California to northern 

 limit in Alaska. Precipitation ranges from about 20 inches in California to over 100 

 inches in Alaska. The temperature drops to —35° F. toward north limit; while over a 

 great part of range, notably at south, and along coast, light frost occurs and tempera- 

 ture goes to zero. 



Tolerance. — Tolerant, but less tolerant than western red cedar and western hemlock. 

 Seedlings endure dense shade, competing successfully with young hemlock. Endures con- 

 siderable side shade in later life, but must have overhead light for best growth after 

 seedling stages. Grows rapidly in height after first few years, and overtakes the slower 

 western hemlock. Alone or in mixture it maintains a dense stand. Permanently over- 

 topped seedlings or older trees remain stunted and grow but iittle, but if shade be dense 

 and persistent they die eventually. 



Reproduction. — Prolific seeder, especially heavy seed years occurring at intervals of 

 two or three years, while some seed is usually borne locally nearly every year. Seed with 

 high rate of germination and of persistent vitality. Germination and growth of seed- 

 lings best on any wet or constantly moist soil ; muck, moss, duff, or decaying wood com- 

 mon to its habitat. Seedlings are sensitive to frost for first few years, but not in later 

 life. Root system, shallow ; in moist ground running near surface beneath moss, duff, 

 and otber debris ; in drier soils, going deeper, when, for good growth, a deep, porous soil 

 is necessary. 



Weeping Spruce. 

 Picea breiceriana Watson. 



DISTINGUISHING CHARACTERISTICS. 



Weeping spruce is a little-known tree, and a comparatively recent discovery. 

 It was permanently brought to light in 1884 by Thomas Howell, but the first 

 discovery probably dates from 1863, when Prof. William H. Brewer, in honor of 

 whom the tree was afterward named, preserved leaves and a branchlet from a 

 weeping spruce tree growing at the west base of Mount Shasta, California. The 

 species has not been rediscovered in that locality. Professor Brewer's speci- 

 mens can be likened only to those from weeping spruce, but the confirmatory 

 evidence of cones, which were not collected, is required to make the identification 

 sure. 



The marked weeping habit of its lower branches distinguishes this tree from 

 its associates. It is thickly branched to the ground, forming a long-pointed, 

 conical crown. The trunk* is greatly swelled at the base and tapers rapidly to 

 the top. The usual height attained is from 50 to 75 feet, with a diameter of 

 18 to 30 inches. Trees 100 feet or more in height occur, but they are excep- 

 tional. The thin, spike-like point of the crown bears short upturned branches, 

 while on the lower crown the branches stand out straight, becoming more and 

 more drooping near the ground. The unique characteristic of the middle and 

 lower crown branches is their numerous, very long, string-like branchlets, which 

 hang down from 4 to S feet in length. These also have numerous pendulous side 

 branchlets. Bark of large trunks is about three-fourths of an inch thick, dark 

 reddish brown, and with thin, long, firmly attached scales. The dense foliage 

 has a somewhat bright but deep yellow-green hue. The leaves (fig. 31) are fiat- 

 tish and obscurely triangular, the sharpest angle on the lower side. Two resin 

 ducts are shown on cross-section of the leaf near its upper border. The cones 

 (fig. 31) mature in one seasou, shedding their seed late in September or in Octo- 

 ber. When full grown, and before opening, they are dark purplish green ; 

 after shedding their seed, they are dull russet-brown. They fall from the trees 

 slowly, many adhering until the end of the second autumn. The seeds are dark 

 chocolate brown. Seed-leaves, as a rule, 0. Wood, little known; pale yellowish 

 to very light brown, rather heavy, and fine-grained. 



