The reasoning behind the name southern red oak tree is somewhat straightforward. This plant's leaves typically turn reddish-brown in fall, which is why the word red appears in the name. The southern red oak is also exceptionally common across the southern United States, hence the name southern. But while that name is an excellent descriptor, this plant can go by others too. Some refer to this plant as the Spanish oak, while others use its botanical name, Quercus falcata.