152 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



following fires have been found which, at the age of 8 years, 

 had a maximum density of 175,000 live seedlings per acre, 

 averaging 2 feet high. 



In dense stands lodgepole forms a tall, slim, slightly tapering 

 stem, with a narrow conical crown. The size is variable, but 

 the average height runs from 60 to 80 feet, with diameter 

 ranging from 7 to 15 inches. Individual trees with a height of 

 100 feet and a diameter of 30 inches have been measured. 



Unlike the eastern Jack pine, lodgepole forests are largely 

 confined to the mountains, reaching an altitude in British 

 Columbia of from 5000 to 6000 feet, and in the United States 

 of 11,000 feet. It is very hardy, and can stand extremes of 

 temperature from 100 degrees F. to 50 degrees below zero. In 

 the lodgepole region the growing season is short, and frost and 

 snow may occur at any time. The habitat is comparatively 

 dry, but it requires a precipitation of over 20 inches to produce 

 well-developed stands. Too much soil moisture is hurtful, and 

 good drainage is essential. It is not exacting in its soil require- 

 ments, but it grows well on rocky and sandy soils, although the 

 best soil is a gravelly loam. 



The U.S. Forest Service say of lodgepole pine — " In relation 

 to its light requirements lodgepole exhibits three striking charac- 

 teristics — intolerance of any considerable degree of overhead 

 shade, ability to survive for long periods in a badly crowded 

 or suppressed condition in pure, even-aged stands, and ability 

 to recover and make increased growth after being released from 

 suppression." In dense stands of lodgepole there are usually 

 large numbers of suppressed trees from 1 to 5 inches in 

 diameter, of the same age as the dominant trees, and these will 

 persist to the end of the rotation. 



The U.S. Forest Service have studied the effects of thinning 

 in lodgepole stands. One tree studied was released from 

 suppression when 94 years old. In 16 years its diameter had 

 increased from 1-44 inches to 5'o6 inches, and its height from 

 15 to 25 feet. The rate of growth increased from 1 inch in 

 diameter in 67 years to 1 inch in 4 years, and from 1 foot in 

 height in 7 years to 1 foot in 16 years. The rate of growth 

 increased 4680%. One stand, 160 years old, contained approxi- 

 mately 3500 trees per acre, no more than 4 inches in diameter; 

 for commercial purposes they were practically of no value. 



Lodgepole within its own range forms large pure stands. At 



