132 



WHITE OAK. 



Quercus alba, Linnaeus. 



FORM A very large and valuable tree, usually attaining height of 70-80 ft. but may reach 

 a maximum height of 140 ft. with a diameter of 8 ft. when grown In a closed stand. When 

 grown in a dense stand (Fig. 11) it has a clean continuous trunk often free from lateral 

 branches for 75 ft. with a diameter of 5 ft., and little stem taper. When grown in the 

 open (Fig. 21) it divides near the ground into a great many lateral branches which are 

 gnarled and twisted forming a deep, wide, and irregular crown or occasionally a symmetrical 

 crown. Open grown trees produce a very small quantity of timber of commercial importance. 



BARE On smaller branches light green to reddish-green; on mature trunks up to 2 inches 

 thick, usually light gray or white, shallowly fissured into flat, irregular scales often very loosely 

 attached. Occasionally the bark of trunk appears roughly ridged and without scales. See Fig. 73. 



TWIGS During first summer light green, tinged with red, coated with loose, pale hairs. 

 First winter slender, smooth, reddish to gray, covered with numerous, light, minute, elevated 

 lenticels. Pith star-shaped. 



BUDS Alternate; terminal buds clustered; broadly ovate, obtuse, reddish-brown, J of an inch 

 long. 



LEAVES Alternate, simple, 5-9 inches long, 2-4 inches wide, obovate in outline, with 3-9, but 

 usually 7 ascending lobes; lobes blunt at apex and separated by deep round-based sinuses. When 

 full grown thin, bright green and smooth above, and pale, smooth, and occasionally glaucous 

 below. 



LEAF-SCARS Alternate, raised, concave to round above, rounded below. A decurrent ridge 

 often continues from raised leaf-scar which makes the twig 5-angled on account of 5-ranked 

 arrangement of leaf-scars. Bundle-scars are numerous, scattered, inconspicuous. The leaf- 

 scars of the Oaks of this State so closely resemble each other that a description of a leaf- 

 scar of one species will suffice for all. 



FLOWERS Flowers appear in May when the leaves are about J developed. Staminate flowers 

 are borne in hairy aments 25-3 inches long. Calyx is very hairy and yellow. Stamens extend 

 beyond calyx. Anthers are yellow and notched. Pistillate flowers are borne on short stalks, with 

 hairy involucral scales and red spreading styles. 



FRUIT An acorn, maturing during one season, sessile or short-stalked. Nut ovoid, rounded 

 at apex, shiny, light brown, 3 of an inch long, inclosed for 1 length in cup. Meat of nut is sweet 

 and edible. Cup bowl-shaped, slightly tomentose on inside, covered with numerous scales whi^h 

 are thin, short, flat, blunt-pointed near rim, thickened and knobby near the base. 



WOOD Ring-porous; with very conspicuous medullary rays; strong, heavy, hard, close-grained, 

 durable in contact with soil, light brown with lighter sapwood. The most valuable of all oak 

 wood. Weighs 46.35 Ihs per cubic foot. Used in construction, ship building, tight cooperage, 

 furniture, railroad ties, manufacture of wagons, agricultural implements, interior finish of 

 houses, fences and fuel. 



DISTINGUISHING CHARACTERISTICS In summer one can distinguish the White Oak very 

 readily by its loose scaly, grayish or white bark from which it takes its common name, and by 

 its deeply round-lobed leaves with a smooth and pale lower surface when mature. In winter 

 it has some characteristics apparently in common with some other Oaks but can be distinguished 

 from the Red, .Black, Scarlet, Chestnut, and Yellow Oaks by its obtuse, rather small buds; from 

 ths Swamp White Oak by the slender reddish to grayish twigs and the absence of dark loose 

 peeling flakes on the branches; from the Post Oak by the absence of greenish rusty pubescence 

 cr the twigs; from the Pin Oak by the absence of stiff lateral pins on the branches and the more 

 obtuse buds; from the Bur Oak by the absence of corky wings on the branches. In addition to 

 these characteristics the acorns and leaves which often persist will aid considerably in recognizing 

 the different species. A careful study of the key to the species will help in bringing out additional 

 distinguishing characteristics. 



RANGE Maine to Minnesota, south to Florida and Texas. 



DISTRIBUTION IN PENNSYLVANIA Abundant throughout the eastern, central, and south- 

 ern parts, and rather common at least locally, in the northern and western parts. 



HABITAT It is tolerant of many soils, growing on sandy plains, gravelly ridges, rich uplands, 

 and moist bottomlands. It reaches its best development in rich moist soil. 



IMPORTANCE OF THE SPECIES The White Oak is the most important hardwood species of 

 Pennsyvania. It is a slow grower but develops an exceptionally high grade material. Artificial re- 

 generation by planting is difficult. Sprouting cannot be depended upon. Natural seed regenera- 

 tion is the best method fcy which this species can be successfully reproduced. German experimenta- 

 tion has shown conclusively that the natural method is superior to the artificial, especially with 

 Oak. The great value of its timber will justify attempts to grow this species In forest stands 

 of considerable extent. 



