AMERICAN SYLVICULTURE 



Seed one-half pound per square pole; seed has 60% germina- 

 tion; cones contain fertile seeds from sixth year on. 



Use yearlings or transplants two to three years old for the 

 very poorest soil, 



B. Pinus ponderosa; Fails absolutely in Germany, probably 

 owing to insuflifient summer heat. 



C. Finns rigida: Very modest; does well in salty swamps; 

 suffers badly from snow-pressure. 



When 5 years old, 7 feet high. 



When 20 years old, 32 feet high. 



Growth is very rapid, but from twelve years on P. sylvestrig 

 catches up and then keeps ahead. 



Diameter growth better than in syhestris, too. 



Strong reproductive power after damage by insects, game, fire. 



Very light demanding. 



Cones seed-bearing from twelfth year on. 



More proof against late frost, more sensitive for early frost 

 than sylvestris. 



Less shedding of needles due to Hysterium; more danger from 

 game. 



Use yearlings, or transplants two years old. 



D. Picea engelmanni; Likes strong but not wet soil — it i3 

 winter frost hard; but suffers slightly from late frosts. 



Root system deep, many fibred; not flat. 



Dislikes top shade. 



Yearling only one to two inches high; two years old four 

 inches high; five years old one foot high. 



Height growth always slov,', hence easily outgrown, and pure 

 stands required. 



Use transplants, five years old. 



E. Picea parrayana: Vevy frost proof, more so than any other 

 Spruce. 



Stands wet soil ; not exacting. 

 Xo top shade. 



Root system compact, fine fibred. 

 Slow early growth, as in Engelmann's Spruce. 

 Plantations ten years old average but one and three-quarter 

 feet in height. 



Animal proof. 



F. Picea sitchensis: Requires moist soil and moist air. 

 Heat requirements as in P. excelsa. 



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