PROLONGING THE SUPPLY. 17 



in the season that the bark did not part readily from the wood, and 

 a very thin portion of the inner bark and cambium layer adhered to 

 the wood and formed a sort of film. This film after one season looks 

 like a thin ooat of brown varnish. The wood beneath, however, is 

 greenish and pulpy, suggesting the mesophyll layer of a leaf. This 

 layer does not increase appreciably in thickness. 



REPRODUCTION BY SEED. 



No other oak on the Pacific coast produces so heavy a crop of 

 acorns as tanbark oak, but seedlings, nevertheless, are not abundant. 

 In the main, forest seedlings are found only where a fallen tree has 

 made a break in the forest canopy and let in light. The "Bald 

 Hills" country is filled with hogs and cattle, which prevent seedling 

 reproduction by devouring the acorns and browsing the tender foli- 

 age of the young growth. 



Attempts at artificial . propagation outside the natural range of 

 tanbark oak have failed. The acorns germinate in open nursery beds 

 in about five weeks. The seedlings come up a little more promptly 

 in loam beds than in adobe, but those in the adobe seem a trifle more 

 vigorous than the others. Sand beds germinate only 2 per cent of the 



Eighty per cent of the seeds planted in 1902 at the California For- 

 estry Station at Chico germinated, but not one seedling survived the 

 first summer, although the soil conditions are favorable. The hot, 

 dry climate of the interior valleys does not furnish a normal environ- 

 ment for tanbark oak, and the formation of plantations is practica- 

 ble only where conditions are similar to those of the natural range 

 of the tre*e. 



SECOND-GROWTH BARK. 



For several years second growth has been peeled in the Santa Cruz 

 Mountains, and it is claimed by some owners who superintended both 

 peelings that the yield of second growth exceeds that of the virgin 

 stand. There is nothing to prove or disprove this assertion, but it 

 is probable that these men did not take account of the fact that the 

 harvesting of the crop to-day is very much closer and more careful 

 than the peeling of the virgin timber from 30 to 50 years ago, and 

 that "passed trees" of the virgin stand were stripped at the sec- 

 ond peeling. Although it is improbable that the yield of second 

 growth at the end of 30 years would equal that of the original 

 stand, it is sufficiently heavy to make the holding of cut-over lands 

 profitable for repeeling in 30 years, when from 1 to 5 cords per 

 acre can be harvested. 



Table 8 gives the yields of a number of second-growth trees in the 

 Santa Cruz Mountains. 



89446 Bull. 7511 3 



