QUERCUS, The Oaks. 



Size. Very variable but nearly all are trees. 



Growth. Rather slow, but very persistent; very long lived. 



Root System. Deep with very strong heart and tap roots. 



Bole. Many have massive, straight, cylindrical trunks. 



Crown. Most have very large, powerful branches forming often 

 extremely wide but storm-firm crowns. 



Tolerance. Intolerant, but too much light causes water sprouts 

 on the bole. 



Wood. Heavy, hard, very strong generally, and porous. In 

 general, the evergreen oaks are the strongest, followed closely by the 

 white oaks, the black oaks being the weakest. Wood and bark both 

 contain much tannin, the precentage varying with the species. 



Reproduction. Seed production is not prolific; more or less 

 periodic at intervals of 1 to 3 years. Flowers in the spring, and is wind 

 fertilized. With four exceptions the acorns of white oaks mature in one 

 season and those of the black oaks in two seasons. Acorns are dis- 

 tributed by water and animals, large quantities being eaten by the latter. 

 Germinate generally in the spring. Seedlings devote early energy to 

 production of a very large and long tap root which enables them to 

 survive repeated ground fires and send up new shoots. By coppice the 

 oaks reproduce very Vigorously and the stumps have very persistent 

 vitality. 



Range. World-wide from Tropical to Middle Temperate Zone and 

 optimum in the latter. In America in the basins of the Ohio and Missis- 

 sippi rivers. Range from sea-level to nearly 10,000 feet in elevation. 



Climate. Cold to tropical; temperate preferred. 



Soil. Cosmopolitan, inhabiting dry, sterile soils as well as moist, 

 fertile ones. 



Association. Often gregarious in optimum; also singly and in 

 groups with other hardwoods and with conifers. 



General. About 300 species known; about 53 in the United States, 

 all trees except three or four. There are 8 species in Canada, 4 of them 

 restricted to the southwest peninsula of Ontario, and 1 to the south end 

 of Vancouver Island. 



In commercial importance the oaks rank the highest of all American 

 hardwoods, because of their high technical qualities and great supplies. 

 In Canada the supply is nearly exhausted, large quantities being im- 

 ported from the United States. The Canadian commercial species are 

 the white, bur and red oaks, which in 1912 supplied 0.2% of the total 

 lumber cut and 2% of the hardwood cut at an average mill price of 

 $29.82 per thousand. 



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