452 Select Plants for Industrial Culture and 



4, 



is sometimes attacked by Scolytus multistriatus. Oak bark contains 

 on an average about 12 per cent, tannin, and fetches now about 4: 

 per ton in the English market. Eitner records the bark of Q. pedun- 

 culata as always somewhat richer in tan principles than that of Q. 

 sessiliflora, the largest yield of either being in spring. Exceptionally 

 16 to even 20 per cent, may be obtained. Extract of oak-bark for 

 tanners' use fetches about 18 per ton in the London market. Hon. 

 Winter-Irving noticed the British oak to withstand an occasional 

 shade temperature of 118 degrees F. in Riverina, New South Wales. 

 The long-continued adherence of dead leaves in the cool and most 

 verdant season renders this oak not so well adapted for pleasure- 

 grounds in the warmer parts of the temperate zone as many others, 

 particularly evergreen oaks. The English oak is however of quicker 

 growth than many other species. At Port Phillip it attains as a maxi- 

 mum to a height of 40-50 feet in twenty years. The variety pedunculata 

 has in the rather dry clime of the San Francisco region shown more 

 quickness of growth than 40 other species of oaks tried there 

 [Hilgard]. The galls, produced by Cynips calicis, are sought for par- 

 ticular tanning, and called in Germany Knoppern. The best oak- 

 bark for tanning is obtained from trees 12-36 years old [Professor 

 Wiesner]. A variety, Q. pubescens (Willdenow), occurring in South 

 Europe, prefers calcareous soil. It is this particular oak, under the 

 shade of which truffle beds are chiefly established. 



Quercus rubra, 



The Red Oak of Eastern North- America. Height reaching about 

 100 feet ; diameter of stem 4 feet. A tree, content with poor soil, 

 comparatively quick in growth. The wood, though course, is of 

 rigidity, and has not the fault of warping ; it is of fair value for 

 staves [Simmonds], and even building purposes, but variable in 

 quality according to soil and clime [Sargent]. The bark is rich in 

 tannin. Autumnal tint of foliage beautifully red. The acorns, 

 which are produced in great abundance, are relished by hogs. The 

 tree is hardy still at Christiania. Circumferential stem measurement 

 at 2 feet from the ground after 22 years about 38 inches 

 [Furnas]. Adopted lately among trees from abroad for the Prussian 

 forests. 



Quercus semecarpifolia, Smith. 



The Karshu-Oak. In the Himalayas and adjoining ranges up to 

 about 12,000 feet. The largest of the oaks of India, upwards of 100 

 feet high, with a stem often 18 feet in girth. Leafless annually for a 

 short time ; not quick of growth. It furnishes a hard and heavy 

 timber of fair quality. The bark, ordinarily dried, contains about 

 8 per cent, of tannin according to Professor Trimble's chemical 

 analysis. The leaves are locally stored for winter forage. An 

 elaborate account of the nature of the wood and the increment of 

 growth is given by J. S. Gamble for this and some other oaks in his 

 manual of Indian timbers. 



