The acorns are the largest of any North American oak (thus the species name macrocarpa, from Ancient Greek μακρός makrós "large" and καρπός karpós "fruit"), and are important food for wildlife.
[3] The wood when sawn transversely shows the characteristic annual rings formed by secondary thickening.
Two varieties are accepted in Kew's Plants of the World Online:[7] Quercus macrocarpa is widespread in the Atlantic coastal plain from New Brunswick to North Carolina, west as far as Alberta, eastern Montana, Wyoming, and northeastern New Mexico.
[8] Bur oaks primarily grow in a temperate climate on the western oak–hickory forested regions in the United States and into Canada.
For this reason, it is an important tree on the eastern prairies, often found near waterways in otherwise more forested areas, where there is a break in the canopy.
[10] The West Virginia state champion bur oak has a trunk diameter of almost 3 m (10 ft).
[13] It forms black pustules on the petioles and causes leaf discoloration and death, making the tree more susceptible to other secondary issues such as Armillaria root rot or Agrilus bilineatus (two-lined chestnut borer).
[13] Quercus macrocarpa is cultivated by plant nurseries for use in gardens, in parks, and on urban sidewalks.
[citation needed] It has been planted in many climates, ranging northwards to Anchorage, Alaska, and as far south as Mission, Texas.
[14] The wood of Quercus macrocarpa is commercially valuable; it is durable, used for flooring, fence posts, cabinets, and barrels.