20 BULLETIN 207, U. S. DEPARTMENT OF AGEICULTUEE. 



spruce, and western yellow pine, while small, practically pure stands 

 are occasionally interspersed with pure stands of pinon pine. 



The exact light requirements of mountain red cedar are as yet im- 

 perfectly known. It endures rather dense shade during the seedling 

 and early sapling stages in moist, cool situations. Later, however, it 

 seems to require top light for height growth, because in close, pure 

 stands and under the dense side shade of other species the trunk 

 branches die. It develops a distinctly thinner and more open crown 

 in protected and shaded situations than in full light. While in early 

 life it has about the same degree of tolerance as eastern red cedar, 

 later on it appears unable to endure as much shade as the latter tree. 



Mountain red cedar is usually a very prolific seeder, especially when 

 growing in the open. Some seed is borne practically every year, but 

 particularly heavy crops are produced at intervals of from 2 to 5 years. 

 Reproduction, however, is generally sparse, which may be due prima- 

 rily to the tardy germination of the seed. The moist soil in pockets, 

 rocky crevices, and on the borders of constantly watered canyons 

 furnish the best seed-beds and are the sites on which seedlings are 

 most often found. Large quantities of the berries are eaten by birds, 

 which assist in distributing the seed. » 



LONGEVITY. 



Little is known regarding the extreme age attained by mountain 

 red cedar. It appears to grow very slowly and to be rather long- 

 lived. Trees from 6 to 8 inches in diameter are from 130 to 175 

 years old. Under favorable conditions of growth, this cedar probably 

 reaches an age of at least 250 years, possibly 300 years. 



ONE-SEED JUNIPER. 



Juniperus monosperma (Engelm.) Sargent. 



COMMON NAME AND EARLY HISTORY. 



This species is commonly called merely "cedar" or "juniper," lay 

 people as a rule not distinguishing it from Utah juniper, with which 

 it often grows. The name one-seed juniper, derived from the tech- 

 nical name of the tree, is appropriate because the small berries usually 

 contain but one seed. This one-seed character, however, can not be 

 depended upon to distinguish Juniperus monosperma from Utah 

 juniper and Juniperus megalocarpa, since both of these have one- 

 seeded fruit. 



There is no record of when this tree was first found by early explor- 

 ers of the southern Rocky Mountain region. The first botanical 

 account of it was published in 1877, when it was named "Juniperus 

 occidentalis var. /? monosperma Engelmann," under which varietal 

 name it was known to botanists until 1896. Investigation then 

 showed it to be distinct from J. occidentalis in its smaller twigs, one- 

 seeded fruit, and in its more southern range. 



