SUGAE PINE. 9 



While there is a fair crop of sugar-pine seed each fall in some por- 

 tion of its range, good seed years throughout occur only at intervals 

 of from three to five years. Cones are occasionally borne by trees 

 from 40 to 50 years old, but the best and most abundant seed is 

 obtained from 125 to 175 year-old trees. The ability to produce seed 

 in large quantities is possessed by huge trees that are long past matu- 

 rity and deteriorating. 



A bushel of cones (about 20, each containing approximately 200 

 seeds) produces 2 pounds of seed, of which from 20 to -50 per cent 

 will germinate. Germination is peculiarly slow, often continuing 

 throughout two fuU seasons in seed beds. This makes the species 

 difficult to handle in the nursery. 



The seed is disseminated principally by wind. Which generally 

 does not transport it over 150 yards, because of its large size and rel- 

 atively small wings. 



On the drier and more exposed situations sugar-pine reproduction 

 can not compete with yellow pine or incense cedar. On humus soils 

 in moist protected spots it succeeds fairly well. Its chief competitor 

 here is the white fir, which has the advantage of bearing abundant 

 hght seed, which is not attractive to rodents. The ability of sugar- 

 pine seedlings to endure shade enables them to contend successfully 

 with brush on moist favorable sites. Sugar pine is much more sus- 

 ceptible to injury from ground fires than white fir, yeUow pine, or 

 incense cedar seedlings, and the absolute exclusion of fire is essential 

 to the securing of a young stand of this species on cut-over areas. 



FOREST TYPES. 



Sugar pine frequently occurs in pure stands covering about an 

 acre, but is never found on larger areas without other species in 

 mixture. Yellow pine, incense cedar, white fir, and Douglas fir are 

 its most common associates, followed by red fir and Jeffrey pine at 

 higher elevations. Occasionally it mingles with western white pine, 

 lodgepolo pine, yew, whitebark pine, limber pine, knobcone pine, 

 coulter pine, and at low elevations with various species of oak. 

 These combinations, however, are only of botanical interest. Largely 

 as a result of repeated fires, stands of sugar pine are generally rather 

 open and contain considerable underbrush, composed of various spe- 

 cies of ceanothus, manzanita, oaks, buckthorns, cherries, serviceberry, 

 and chinquapin. 



For descriptive purposes, stands containing sugar pine have been 

 divided into the following cov<t types, based upon the number of 

 trees of each species that are found in mixture. 

 oo380°— Bull. 420— If 2 



