Although Oak identification has distinct difficulties, recognizing an Oak to genus is relatively simple and a few of our common species can easily be learned. Oaks are divided into two groups. White Oaks have round leaf lobes and produce acorns every year. Red Oaks have pointed lobes and produce acorns on two year cycles. Red Oaks are also known as Black Oaks. Usually, this depends on whether the region has Red Oak (Quercus rubra) or Black Oak (Quercus velutina) as a dominant species. Red Oak, though, can also be used with the somewhat politically incorrect mnemonic that the white man shot bullets, which are round, while the red man shot arrows, which are pointed.
Check out the USDA map for these two species. By zooming in on the map county level distribution is shown.
You might also note that the above-mentioned taxonomic complexity is further illustrated with two varieties of Red Oak. Red Oak is dominant in the parts of our region I am familiar with, though Black Oak does occur. Others in the group, which also hybridize with Red Oak, include Scarlet Oak and Scrub Oak.
Red Oaks are considered less desirable than Whites as a source of acorns, mostly because of their fruiting cycle and higher tannin content. Tannins make acorns astringent. Fortunately, they can be leached out with cold water. Since White Oaks produce less astringent acorns they are more efficient to prepare.
White Oak is a common species of our forests. It is a beautiful and important tree, producing superior acorns and hard wood for craft and fuel. White Oak is an ideal firewood from our area.
For medicinal virtue, it is the tannins that we give credit. All Oaks have astringency, which we usually find in the bark or acorns for medicinal use. I assume the leaves are plenty astringent too, but know little of their constituency besides and do not make use of them. In the bark and acorns we find a pretty pure astringent that can be used practically whenever astringency is called for in the preparation.
The Cherokee used White Oak to treat diarrhea, mouth sores, chapped skin, fevers, indigestion, debility, asthma, milky urine, and lost voice. The Lenape used for cough, sore throats, gynecological problems, bruises, ulcers, Huoma used as an antirheumatic. Iroquois used for loneliness and consumption. Mohegan used for muscular pains, colds,
Scrub Oak was used by the Iroquois.