58 FOREST TEEES OF THE PACIFIC SLOPE. 



Dee;: Creek and Grass valley drainages, Bear Valley (6,700 feet), south side Little Bear 

 valley, Santa Ana and City Creek canyons, but not west of Strawberry Ridge nor east of 

 Coxey Ranch. Common in San Jacinto Mountains at 4,500 to 6,500 feet, sometimes down 

 to 3,500 feet and up to 7,000 feet or 7,500, as above Strawberry valley ; only on south 

 and west sides of mountains. Santa Ana Range only at head of Trabuco Canyon and 

 southwest side Santiago Peak nearly to summit. Palomar or Smith Mountain (south- 

 west of San Jacinto Mountains) only below Iron Spring. Common in Balkan Mountains 

 to the south and in northern part of Cuyamaca Mountains at 4,500 to 7,000, and some- 

 times down to 4,000 feet ; noted near Julian at 4,100 feet. Laguna Mountains (north 

 of Mexican line), only on crest of east side. 



Lower California. — Not within some miles of international boundary, but farther 

 south in Hanson Laguna Range above 4,000 feet and south to Mount San Pedro Martir 

 at 8,000 to highest summits (11,000 feet). 



OCCURRENCE. 



On dry, warm slopes and ridges, as well as sometimes on more moist, sheltered north 

 slopes in chaparral. In dry gravelly loam soils. 



Never in pure forests. At lower altitudes, singly or in groups on summits, in shel- 

 tered ravines, and hill coves; higher up (from 3,500 to 5,000 feet), with incense cedar, 

 yellow pine, big-cone spruce, and oaks ; sugar pine and white fir appear with it between 

 5,500 and 7,000 feet, but here Coulter pine soon thins out and disappears. 



Climatic Conditions. — Temperature on coastal mountain slopes 25° to 35° P. and 

 from 15° to 100° F. on inland mountains. Humidity high near coast, where cloudy, 

 foggy days are frequent, and low toward inland, or eastern limit of range. Precipita- 

 tion, from 20 to 30 inches, and chiefly rain. In southern inland mountains it some- 

 times endures almost arid conditions, with long drought and rapid evaporation during 

 summer. 



Tolerance. — Demands light except in youth, when it endures shade of chaparral. 



Reproduction. — Persistent, periodic seeder, bearing cones often when 10 to 15 feet 

 high, and usually in three-year cycles. Germination of seed only moderate, and vitality 

 (out of cones) transient.. Heavy seeds; ripe in August, shed very slowly, sometimes not 

 until or after following January ; they commonly fall close to seed frees. Reproduction, 

 never dense, is usually scattered and on exposed mineral soil and where there is little 

 humus. 



Monterey Pine. 

 Pinus radiata Don. 



DISTINGUISHING CHARACTERISTICS. 



Monterey pine is unique in its isolated sea-coast habitat, where, according to 

 . exposure and density of stand, it has a comparatively tall, clean trunk topped 

 by a conspicuously open, irregularly long, and large branched crown. Old trees 

 are apt to have flattish crowns, while younger trees usually have narrow, 

 rounded crowns. The dense foliage is brilliant deep grass-green. Trees from 

 60 to 90 feet in height and from 16 to 24 inches in diameter are common, but 

 a height of nearly a hundred feet and a diameter of 3i or 4 feet, and occa- 

 sionally 5 or G feet, is sometimes attained. Bark of adult trees is a deep red- 

 dish or blackish brown. It is broadly ridged and deeply furrowed, the flat 

 ridges cut into close, distinct plates. Leaves of a season's growth, which are 

 slender and about 4* to 6 inches long, remain on the tree until the third year. 

 They occur chiefly 3 in a bundle, with occasional clusters of two on the same 

 branch or tree (fig. 19). A form of this tree (/'. radiata var. (6) binnata Lem- 

 mon (1895) = P. insignia var. binnata Wats., 1876) growing on the California 

 coast islands Santa Cruz and Santa Rosa, has most of its leaves 2 in a bundle, 

 but not infrequently bundles of 3 on the same tree. Otherwise, the characters 

 of this form are the same as those of the mainland tree. Other North American 

 pines (Pinus echinata) exhibit similar variations, which, like those of the 

 present tree, are deemed insufficient to establish varieties. The cones (figs. 



