42 FOREST TREES OF THE PACIFIC SLOPE. 



attached to the tree. Seeds dark hrown with areas of yellov-brown. An 

 unusually large number of seed leaves are developed by seedlings, from 12 to 

 14 being the usual number. Wood, pale reddish-brown, soft, very brittle, and 

 wide-grained. This tree is of such rare and limited occurrence that the wood is 

 of no commercial importance. 



Longevity. — Little is known of the longevity of this pine, which is rarely 

 cut. Trees from 10 to 12 inches in diameter are from 75 to 80 years old. 

 It appears to be a comparatively short-lived pine ; its ordinary age is probably 

 from 100 to 150, and not more than 200 years. 



RANGE. 



Confined to a limited area in San Diego County and to Santa Rosa Island, southern 

 California. On the mainland it occurs in a strip about 1 mile wide on both sides of 

 the mouth of Soledad River, from a point on the north 3 miles north of Del Mar, a 

 mile and a half from the Pacific coast, to a point 5 miles south of Point Pinos. 



OCCURRENCE. 



Highlands adjacent to sea and on sides of deep ravines and washes leading to coast. 

 On mainland growing in a disintegrating yellowish sand rock. On Santa Rosa Island, 

 in a soil of mingled earth and loose rock, or sometimes in rather thick soil over un- 

 broken rock. Largest trees on sheltered sides of hills and spurs of canyons protected 

 from sea winds ; sprawling and distorted in exposed situations. Much scattered and 

 with little or no other growth except thin chaparral. 



Climatic Conditions. — The temperature of its range varies annually between 25° and 

 05° P. About 15 inches of rain falls during the year. The air is humid and a large 

 proportion of the days are cloudy or foggy. 



Tolerance. — Apparently demanding full light, as shown by scanty foliage and growth 

 in very open, scattering stands. Little is known of its silvical characteristics. 



Reproduction. — Prolific, annual seeder, bearing well when from 12 to 18 years old. 

 Seeds discharged mostly during third year, the cones with remaining seeds falling about 

 the fourth year. Germination takes place in crevices and washed mineral soil. Seed- 

 lings are rather numerous in vicinity of trees, both on mainland and on Santa Rosa 

 Island. 



YELLOW PINES. 



Western Yellow Pine. 



Pinm ponderosa Lawson. 



DISTINGUISHING CHARACTERISTICS. 



This is a massive, straight-trunked tree with a long, narrow, open crown of 

 hugely developed bent branches. The narrow columnar crown, with scattered 

 branches, upturned at their ends, is characteristic. Often one or two large 

 lower branches are separated from the crown by 20 or more feet of clear 

 trunk. Trees grown in an open stand bear branches close to the ground, retain- 

 ing this long low crown throughout life. The trunk is smoothly cylindrical, 

 with little taper until the large crown branches are reached. Height, from 125 

 to 140 feet, with a practically clear trunk of from 40 to 60 feet ; diameter, from 

 3 to 4 feet. Its majestic size is surpassed among its kind only by the sugar 

 pine. Unusually large trees are from 150 to 180 feet high, while trees are said 

 to have been found over 200 feet high. The largest diameter recorded is about 

 8 feet. The bark of old trunks is marked by very' broad, shield-like, russet-red 

 plates, which may be from 3 to 4 inches thick, especially near the base of the 

 tree. The surface of this bark is peculiar in being made up of small, concave 

 scales. Younger trees, up to 2 feet in diameter, are quite unlike older ones in 

 having dark red-brown or blackish, narrowly furrowed bark. Young shoots, 

 which have a strong odor of orange when broken, are yellowish green and 



