22 BULLETIN 207, TJ. S. DEPARTMENT OP AGEICULTUEE. 



in exceptional cases being two or three seeded. The fruit of some trees 

 is peculiar in having the top end of the seed partly exposed. The 

 seeds (PI. XI, a) are pale chocolate-brown and marked at the base 

 with a two-lobed, whitish scar (hilum). The seed-leaves are two 

 in number. 



The wood of one-seed juniper is very narrow-ringed, hard, and 

 heavy, with a slight cedarlike odor. The sapwood is nearly white 

 and from three-fourths to about 2 inches thick, usually much thinner 

 in old trees than in young ones. The heartwood varies in color from 

 dull yellowish-brown to pale reddish-brown. When thoroughly 

 seasoned it is very durable, and is one of the best and most frequently 

 used woods for fence posts and fuel in arid parts of the Southwest. 

 The fact that the tree is small, crooked, and knotty confines use of 

 the wood to such local but important purposes. Heartwood of old 

 trees grown in protected situations is fairly soft and straight-grained, 

 and blocks would be suitable for certain grades of lead pencils. 



OCCURRENCE AND HABITS. 



One-seed juniper grows in the dry, rocky, or gravelly soils of high 

 desert plains and mountain slopes, at elevations between 3,500 and 

 7,000 feet, though it occurs most extensively between 5,000 and 6,500 

 feet. It forms an open woodland type of forest, and sometimes pure 

 stands of limited extent, but it is more often mixed with Utah juniper, 

 alligator juniper, pinon, and single-leaf pines, and occasionally with 

 western yellow pine and Pinchot juniper (Texas). 



Little is known of this juniper's requirement of light. It can 

 probably endure considerable shade in the seedling stages of growth, 

 but the fact that the older trees invariably have open crowns indi- 

 cates that it requires full sunlight for its later development. 



One-seed juniper is a prolific but irregular seeder, and young 

 plants are found only where through washing or in some other way 

 the seed has become buried in mineral soil. Scanty reproduction is 

 due without doubt to the usually dry and generally unfavorable 

 condition of the soil on which the seed falls. A large part of the 

 seed probably never finds sufficient covering or enough moisture to 

 induce germination. 



The tree's persistent growth on high desert plains and mountain 

 slopes makes it important in the maintenance of protective woodland 

 cover in the Southwest. 



LONGEVITY. 



In the more favorable situations the growth of this species is gen- 

 erally uniform and fairly rapid for a juniper. In arid soils and on 

 exposed sites, however, the growth is irregular and often extremely 

 slow. The exact age that one-seed juniper may attain has not yet 



