244 FOREST TREES OF THE PACIFIC SLOPE. 



Climatic Conditions. — The exceedingly wide range from the Atlantic to the Pacific 

 region and from low to very high elevations shows adaptation to very varied climatic 

 conditions, which, for the Pacific range, are essentially a combination of those already 

 given for the many associates of aspen. 



Tolerance. — Very intolerant of shade throughout life. Its light foliage permits growth 

 in crowded stands, under which there is usually a more or less dense herbage. Mingled 

 with shady conifers, intolerance of even side shade is quickly shown by long, clean 

 stems and small narrow crowns in full light. 



Reproduction. — An exceedingly prolific annual seeder. Seed of high germination but 

 of transient vitality, usually germinating shortly after being shed. Extreme buoyance 

 results in very wide dissemination by wind. Germination best and mainly in moist, 

 exposed mineral or slightly humous soils. The fact that its numerous seeds are quickly 

 and widely scattered over burned and other cleared lands accounts for its being the 

 first tree growth in many localities, where, however, it is often replaced or gradually 

 crowded out by shade enduring associates. It is persistently present more as a result of 

 extraordinarily prolific and constant reproduction than of power to cope with Its 

 aggressive associates. 



Balm-of-Gilead. 



Popiilus balsamifera Linnreus. 



DISTINGUISHING CHARACTERISTICS. 



The balra-of-Gilead, " balsam poplar," or " taeamabac," as it is also called, 

 is distinguishable in general appearance by its lustrous, very dark green leaves, 

 which, as they tremble and turn in the breeze, show glinting flashes of their pale 

 green and bright rusty brown under surfaces. Height, from 75 to 80, sometimes 

 90, feet and diameter from 30 to 40 inches ; very old trees are from 4 to 6 feet 

 through. Stem straight and clear of branches for from 30 to 40 or more feet; 

 the large thick limbs, trending upward strongly, form a rather long, narrow, 

 and irregularly open crown. The bark of large trunks is slightly reddish gray 

 and has regular deep furrows and wide ridges, while that of the limbs and young 

 trees is brownish-gray, sometimes with a greenish shade, and is smooth. Year- 

 old twigs are clear, shiny red-brown, with conspicuously large, sticky buds 

 (fig. 106). End buds are about an inch long aud buds from the sides of twigs 

 are from five-eighths to three-fourths of an inch long. The bud-scales are thickly 

 coated with a yellowish, pungently fragrant balsam, with which the young leaves 

 are also covered. Mature leaves (fig. 100) are thin, somewhat leathery, smooth, 

 clark shiny green on the upper surface, light green or often rust-colored, and 

 very veiny beneath ; from 3i to about 5 inches long and 2 to 3 inches broad ; 

 leaf stems smooth, very slender, round, and from If to about 2 inches long." 



Wood, of light weight, soft, rather fine-grained, pale brown ; not distinguish- 

 able in general appearance from that of other timber poplars. The large trunks 

 give clear, wide lumber which is being more and more used for box and cooper- 

 age stock in place of pine and other more valuable timbers, as well as for paper 

 pulp. Its commercial uses are likely to increase in the future. 



Longevity. — Not fully determined. Trees from 14 to 17 inches in diameter 

 are from 40 to 50 years old. 



RANGE. 



Alaska to Hudson Bay and Newfoundland ; southward to northern New England and 

 northern New York, central Michigan and Minnesota, South Dakota, northwestern 



"A well-marked variety is PopuJus balsamifera candicans (Ait.) Gray, a large tree 

 with less upright branches, more open crown, and with wide heart-shaped leaves, which 

 are usually silvery whitish beneath, minutely hairy on their margins, mid- and other 

 veins, and on the leaf stems (fig. 107). It has been long cultivated for ornament in 

 eastern United States and Canada, but nothing authentic is known of its native range. 



