Rocky Motuitain Seedling Growth loi 



these trees probably invariably occur in the same stand with the 

 older, and vary from one to five or six feet in height, while the 

 older vary within much greater limits, viz. .about three to forty- five 

 feet. This great variation corresponds to variation in situation 

 and density. The latter varies from looo to about 8000 trees per 

 acre. The reproduction under virgin forest is very much 

 scattered and dwarfed, and of widely varying ages. A tree of 

 the latter type was found to be 60 years old and one foot high. 

 The other extreme occurred in an open stand following the fire 

 of 50 years ago. This gave a tree 45 years old, 45 feet high, 

 and 1 1 inches in diameter. Another of the same age made a 

 growth of 16 inches per year for the last 20 5^ears. The best 

 reproduction considered as a forest occurs on cool, moist, northerly 

 slopes. The drier, warmer slopes, where any reproduction took 

 place at all, show an open or scattered stand. The individual 

 here is larger on the average, and its diameter in relation to its 

 height one-third greater. 



Reproduction surveys indicate that Engelmann Spruce in these 

 conditions requires an average of 27 years to reach breast height ; 

 Red Fir, 19 years. The former, under best conditions, first 

 bears cones at 25 years of age ; lyimber Pine, at about 20 years. 

 At least two instances were observed where Engelmann Spruce 

 about 3.S years old had reproduced. 



Of the four principal species. Bull Pine ranks first in average 

 rapidity of growth up to 40 years of age. Red Fir probably 

 takes second place, Limber Pine third, and Engelmann Spruce 

 fourth. 



The ratio of heartwood to sapwood in the sapling of the three 

 species last named above, will be nearly as two to one. In 

 Engelmann Spruce, the number of annual rings in the heartwood 

 will approximately equal the number in the sapwood. In Red 

 Fir, the number is about 25 per cent greater in the former than 

 in the latter, and in Eimber Pine, 10 to 15 per cent greater. 



Many observations show that seed of the three species just 

 named needs bare mineral soil on which to germinate. Recent 

 broadcast sowing of the Bull Pine in the Black Hills indicates 

 the same thing for that species.* Surprise has been expressed 

 at this in certain quarters. John Muir notes the same fact in 

 the Sequoia of the Sierra.* Thos. Southworth, Director of 



^Forestry Quarterly, Vol III, page 412. 

 ^Mountains of California, page 191-192. 



