AMERICA>J 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 insuilii'ient summer heat. 



C. Pinus 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. sylvestris 

 catches up and then keeps ahead. 



Diameter growth better than in sylvestris, 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 is 

 winter frost hard; but sutlers slightly from late frosts. 



Eoot 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 slow, hence easily outgrown, and i)ure 

 stands required. 



Use transplants, five years old. 



E. Picea parrayana: \'erv frost proof, more so than any other 

 Spruce. 



Stands wet soil; not exacting. 

 No top shade. 



Root system compact, fine fibred. 

 Slow early growth, as in Engelmann's Spruce. 

 Plantations ten years old average but one and throo-quarter 

 feet in height. 



Animal ])rn()f. 



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

 Heat requirements as in P. excelsa. 



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