1901 



AMERICAN FORESTRY ASSOCIATION. 



"3 



tions and not crowded by near neighbors 

 may develop with reasonable rapidity, as 

 is shown by an example taken from a 

 mountain slope at an elevation of 9,500 

 feet. This tree at the age of 52 years was 

 42 feet high, 12% inches in diameter, 

 breast high, and had added the last inch 

 to its diameter in a period of five years. 



This development, however, must be 

 regarded as exceptional. The stand of the 



of four inches and over at breast height. 

 Of smaller trees there are 184 Lodgepole 

 Pine and one Balsam, and of small seed- 

 lings two Douglas Fir, one Balsam, one 

 Engelmann Spruce, three Aspen and two 

 Willow. There is no other vegetation 

 except a few small patches of the low 

 mountain huckleberry ( Vaccinium tnyrtil- 

 /us) and a few plants of Prince's" Pine 

 ( Chimaphila umbellata'). The dead trees 



SLOPES ON NORTHERN SIDE OF GRAYBACK RANGE, SAN BERNARDINO FOREST 



RESERVE, CALIFORNIA, BEARING LODGEPOLE PINE AND 



LIMBER PINE. ALTITUDE 11,000 FEET. 



species is usually dense, and much of the 

 area it occupies consists of mountain slopes 

 or elevated plateaus where the combination 

 of excessive dryness and close crowding 

 admits only very slow development as the 

 following example will illustrate : 



An acre of ground on the gently sloping 

 top of a mountain ridge at an altitude of 

 9,500 feet carries 773 Lodgepole Pine and 

 three Douglas Fir trees, having diameters 



on the acre number 293, 85 of which have 

 fallen ; these all belong to the same genera- 

 tion as the living trees, ami represent, in 

 part, the natural thinning through crowd- 



ing. 



Ninety-two per cent, of the 773 Lodge- 

 pole Pine trees fall below ten inches in 

 breast-high diameter, and only two per 

 cent, reach twelve inches and over. From 

 six selected sample trees, it is found that 



