82 MISC. PUBLICATION 9 0, U. S. DEPT. OF AGBICULTUEE 



Its massive trunk and heavy limbs with clusters of deep yellow-green 

 leaves on thin upturned tips make it easy to distinguish. 



Occurrence. — The tree is found rather generally over Utah but is 

 abundant enough to be of commercial importance only in the south- 

 ern part of the State, where it is found at elevations of from 6,000 

 to 9,000feet. 



Requirements. — Western yellow pine is distinctly a light-demand- 

 ing species. Up to 15 or 20 years of age it will thrive when densely 

 crowded, but as the tree becomes older it demands almost full sun- 

 light and dies rapidly if overtopped. In regard to soil and moisture 

 conditions, this species is not so exacting. Though generally found 

 on dry sandy exposures, it will thrive on moist sites if the competition 

 from tolerant species, such, as Douglas fir and alpine fir, is not too 

 great. 



Reproduction. — The cones, from 3 to 6 inches long, require two 

 seasons to develop. They mature in late August and scatter their 

 seed mainly during September. Some seed is borne every year, 

 but crops usually occur at intervals of three to five years. In 

 favored localities trees may bear seed when less than 50 years old, 

 but in forest stands a tree is normally 80 to 100 years old and over 

 20 inches in diameter before it becomes valuable for seed production. 

 A mature tree can seed about one-fourth acre in a good seed year. 



Growth and yield. — Western yellow pine is a massive straight - 

 trunked tree which lives to a considerable age and attains a large 

 size. Trees in commercial stands average 30 inches in diameter and 

 200 years in age. A tree 60 inches on the stump was recently found 

 to be 575 years old. The average yield of good western yellow 

 pine in Utah varies from 5,000 to 10,000 board feet per acre. 



Fire resistance. — Western yellow pine is very resistant to fire after 

 reaching maturity, largely because of its thick bark and deep root 

 habit, its high open branch habit, and the freedom from under- 

 growth in the mature pine forest. Saplings and small poles less 

 than 8 or 10 inches in diameter are easily killed by fire. 



Characteristics of the wood. — Young trees have moderately hard, 

 resinous, strong wood. The wood of large mature trees is soft, even 

 textured, and only slightly resinous. Great care must be exercised 

 to prevent damage from blue stain during the summer months. The 

 sapwood of logs or green lumber is quickly attacked by the stain 

 during warm, moist weather. While blue stain is not a form of 

 decay and does not materially weaken the lumber, it makes it unsuit- 

 able for a natural finish and greatly reduces its value. To prevent 

 bluing, logs cut in July and August should be sawed at once when 

 they can not be put into a mill pond. During the summer months 

 special care should be taken to pile lumber which can not be air- 

 dried in a kiln, so that it will dry as rapidly as possible, and thus 

 reduce the damage from blue stain to a minimum. 



Commercial importance. — Practically half of the annual cut of 

 lumber in Utah is western yellow pine. For the most part this 

 lumber is cut far back from the railroad and utilized locally. 



PINON PINE 



There are two species of pinon or nut pine in Utah, Films edulk 

 and P. monophylia. P. edulis has two short needles in a bundle; 



