422 FOREST TEEES OF THE PACIFIC SLOPE. 



Grove, and extending eastward to Pioneer, and for about 3 miles along summit of ridge 

 on north side of Mokelumne River Canyon (above Defender) at 2,700 to 3,000 feet. 

 Sierra National Forest, one grove of large trees on north slope of Pilot Ridge on Pack- 

 ards Camp Stream (tributary South Fork Tuolumne River, lat. 37° 45'), southern limit 

 now known in Sierras. 



OCCUBBENCE. 



Foothill and low mountain slopes of every aspect, borders of streams, cool canyons 

 and valleys; in well-drained, moist, rich, rocky, or loamy soils (here largest) to dry, 

 loamy, or poor gravelly soils (here small or shrubby). Best growth near sea under 

 influence of fogs. Forms small pure stands, but more commonly an undergrowth with 

 redwood, tanbark oak, Douglas fir, California laurel, goldenleaf chinquapin, broadleaf and 

 vine maples, California live oak ; frequent in open stands of western yellow pine and 

 Kellogg oak, and less often with gray pine. 



Climatic Conditions. — Similar to those of yellow pine and Douglas fir. 



Tolerance. — Appears very tolerant of shade throughout life. Endures dense shade, 

 hut requires at least partial top light for best growth ; dense side shade cleans long, 

 slender trunks. 



Reproduction. — Abundant seeder. Exact seeding habits undetermined, especially in 

 the open. Seed has moderately high rate of germination, and persistent vitality. Germi- 

 nation best and most abundant in moist soil when seed is well covered; otherwise (as in 

 drier places) tardy and seedlings scarce. 



Family OLEACEiE. 



Popularly known as the olive family, an important group of forest trees and 

 shrubs, widely represented in warm and temperate countries, particularly those 

 of the northern half of the world. It includes the world-famous olive-tree, cul- 

 tivated centuries ago in Syria and Palestine, later in the Mediterranean coun- 

 try, and now, in addition, in our southwest and in California ; it includes also 

 the ashes — very valuable timber and ornamental trees — and such popular shrubs 

 as the lilacs, the gorgeous yellow-flowered Forsythias, sweet jessamines, and 

 the privets, the latter much planted for hedges. All are similar in having their 

 leaves arranged in pairs (one opposite another). Flowers of some are all per- 

 fectly bisexual, those of others are either male or female, each kind borne on 

 different trees ; those of yet others are both bisexual and unisexual on the sam« 

 tree. 



Some 20 different genera are known in the world, 5 of which are represented 

 in the United States. Three groups of these contain tree species. One genus, 

 Fraxinus, has species distributed from the Atlantic to the Pacific region, 

 whereas the other groups belong entirely to our eastern forests. 



FRAXINUS. ASHES. 



All the ashes except one are trees, and without exception all are known as 

 ashes. Some are very large trees, commercially valuable for their timber, 

 which is straight-grained, hard, and elastic. They grow naturally in a variety 

 of soils, from wet, boggy swamps to the driest and poorest uplands, but most 

 of them thrive best in moist, rich soils. A few form a large part of the forest 

 in which they grow, while others constitute considerable, but only scattered, 

 elements in it. Still others are unimportant stragglers, often confined to nar- 

 row rocky banks of stream courses. 



With few exceptions, they have straight, evenly tapered trunks, and grayish, 

 regularly and rather finely ridged bark. Their leaves, arranged in pairs, are all 



