386 GENERAL BOTANY 



years ; but " under normal forest conditions acorns are not 

 produced, as a rule, before the seventieth or eightieth year." 

 Moreover, a large proportion of the seed is destroyed by worms, 

 rodents, and other animals having access to the forests or wood 

 lots where oak trees are found. The heavy acorns are distrib- 

 uted mainly by gravity or by squirrels which bury them and 

 never dig them up again. The white oak, therefore, is not so 

 well adapted as trees with winged seeds, like the spruces and 

 pines, to disseminate itself where it has been destroyed by lum- 

 bering or by forest fires. Vegetative reproduction often takes 

 place, however, in such situations by the outgrowth of sprouts 

 from the stumps, which maintain this power of vegetative 

 reproduction for long periods. 



Commercial importance. White oaks are chiefly valuable for 

 timber and lumber, although, where they are native, they form a 

 beautiful ornamental tree with dense shade. The wood (Figs. 47 

 and 55) is very dense and hard, with great resistance to disease 

 and decay, both when alive and when used for railroad ties or 

 timber in construction work. Its main uses are for sawed lum- 

 ber, switch ties, and timbers for ships and bridges and for tight 

 cooperage. 



A considerable portion of the lumber from the best logs is 

 quarter-sawed and then shipped to furniture and cabinet factories, 

 where it is used as a substitute for other woods, such as black 

 walnut, cherry, and mahogany. The broad wood rays add greatly 

 to the beauty and value of quarter-sawed oak (Fig. 50). Tight- 

 cooperage staves were early made from white oak for the preser- 

 vation and shipping of alcohol, wines, and liquors, as well as for 

 oil, molasses, and other fluid or semifluid substances which must 

 be confined in tight receptacles. The compact, hard wood of the 

 white oak is admirably fitted for such purposes. In shipbuilding 

 and in making piles for bridges white oak is also very valuable, 

 for the reason that it does not readily deteriorate in situations 

 where it is subjected to alternate dry and moist conditions. 



Like most of the valuable forest trees white oak is rapidly, 

 diminishing in amount and quality, so that its propagation is 

 an important forestry problem. 



