PINE TREES OF ROCKY MOUNTAIN REGION. 35 



or less one-sided (oblique), which is due to the greater development 

 of scales on one side (PI. XXI). In falling from the branches the 

 cones leave a few basal scales attached to the limbs (PL XXI, b), 

 as in the case of Pinus ponderosa and other yellow pines of this 

 group. The ends (umbos) of the cone scales are recurved, elongated 

 (especially on the fuller side of the cone), sharply two-sided, the 

 extreme ends being contracted abruptly to a short delicate prickle 

 (PL XXII, a). The seeds (PL XXII, &)• are a dark chocolate- 

 brown (deeper on the lower side) and from about five-sixteenths to 

 three-eighths of an inch long. Perfect seeds are produced chiefly in 

 the middle third of the cone, many scales bearing only one seed. 

 The seed-leaves vary from 8 to 10, averaging about 9. 



The wood of Apache pine is rather heavy (actual weight undeter- 

 mined), hard, somewhat "cross-grained," and uniformly wide- 

 ringed, the darker bands of late wood forming from one-third to 

 about one-half the annual layers of growth. The wide-ringed char- 

 acter of this wood is due probably to the fact that the trees usually 

 grow in scattered open stands where an abundance of light stimulates 

 diameter growth. 



OCCURRENCE AND HABITS. 



Pinus apacheca grows in the rocky gravelly soils of benches, 

 gulches, and gentle slopes, at elevations of from about 5,700 to 8,200 

 feet, and usually in moderately moist situations (map No. 11). It 

 forms a very open stand or is widely scattered, and is associated more 

 or less with Arizona pine, Chihuahua pine, western yellow pine, 

 Arizona oak, whiteleaf oak, and huckleberry oak. 



It is intolerant of shade except during the first five or six years 

 of its life. 



Apache pine bears abundant crops of seed; good seed years occur 

 only at intervals of about two or three years, but some seed is pro- 

 duced practically every year in parts of the tree's range. Wind car- 

 ries the large- winged seeds (PL XXII, b) several hundred feet from 

 the parent trees, but as many of them fall where germination can not 

 occur for lack of soil cover, reproduction is not abundant and is 

 always scattered. Reproduction occurs most readily on broken and 

 washed mineral soil. The seeds of this pine are favorite food of 

 birds and rodents, which consume large numbers of them. 



LONGEVITY. 



The age limit of Apache pine is imperfectly known at present, 

 but the tree probably attains an age of from 175 to 200 years. Trees 

 from 15 to 18 inches in diameter are from 65 to 90 years old, and 

 trees 20 to 28 inches are from 100 to 140 years old. Between the 

 ages of about 8 and 75 years this pine appears to grow rapidly in 

 height and diameter, 



