[3] The oaks of this country, which number more than fifty species, have been classified in different ways, depending upon the purpose in view. In the present treatment they will be divided in two general groups, white oaks and black oaks. No effort will be made to draw hard and fast lines, because it is not necessary. Oaks which ripen their acorns in one year are listed as white oaks; those with two year acorns, as black oaks. This is a botanical rather than a lumberman’s classification; yet lumbermen recognize it in a general way. White oak (_Quercus alba_) is clearly entitled to head the list of white oaks, and red oak (_Quercus rubra_) should occupy a similar position with regard to the black oak group. In numbers, the white oaks and black oaks are nearly equally divided, one authority giving twenty-seven species of white oak and twenty-five of black oak in the United States; but botanists differ as to exact numbers of each. The following species are usually classed as white oaks: White oak (_Quercus alba_), valley oak (_Quercus lobata_), Brewer oak (_Quercus breweri_), Sadler oak (_Quercus sadleri_), Pacific post oak (_Quercus garryana_), Gambel oak (_Quercus gambelii_), post oak (_Quercus minor_), Chapman oak (_Quercus chapmani_), bur oak (_Quercus macrocarpa_), overcup oak (_Quercus lyrata_), swamp white oak (_Quercus platanoides_), cow oak (_Quercus michauxii_), chestnut oak (_Quercus prinus_), chinquapin oak (_Quercus acuminata_), dwarf chinquapin oak (_Quercus prinoides_), Durand oak (_Quercus breviloba_), Rocky Mountain oak (_Quercus undulata_), California blue oak (_Quercus douglasii_), Engelmann oak (_Quercus engelmanni_), Rocky Mountain blue oak (_Quercus oblongifolia_), Arizona white oak (_Quercus arizonica_), Toumey oak (_Quercus toumeyi_), netleaf oak (_Quercus reticulata_), California scrub oak (_Quercus dumosa_), live oak (_Quercus virginiana_), Emory oak (_Quercus emoryi_).
White oak grows in all the states east of the Mississippi river, and it crosses that stream two or three hundred miles in some places. It reaches eastern Nebraska and eastern Kansas, and runs southward through Oklahoma to the Brazos river, Texas. It is scarce in the northern parts of Michigan, Wisconsin, and Minnesota. Its total range covers an area of more than 1,000,000 square miles. Like all other important timber trees, it has regions where the species is best developed. The finest original stands of white oak were found in the upper Ohio valley, beginning in Indiana. The timber in many other districts was, and in some still is, very good, such as southern Michigan, eastern Arkansas, some of the Appalachian valleys and slopes, and in certain places along the upper tributaries of streams flowing into the Atlantic ocean.