Native Oaks of North America

Native Oaks of North America

The oak family (Quercus sp.) is the most important source of hard mast in hardwood forests across North America. Along with the hickory family (Carya sp.), oaks were the dominant species in the oak-hickory forest, a type of forest cover that once dominated the eastern woodlands of North America from New York to Georgia and from the Atlantic seaboard to Iowa and northeastern Texas. The oak-hickory ecosystem had the largest range of any of North America’s native deciduous forests.

Oaks also played an important role in the forests of California, which are home to at least 19 native oak species, many of which are found only in California. In addition to being an important food source for wildlife in the state, acorns were also the staple food of California’s American Indian tribes. Nutritious and easy to gather, the acorns were collected, leached to remove the bitter tannins, and pounded into flour to make acorn mush or bread. John Muir called these acorn cakes “the most compact and strength giving food” he had ever eaten.

Throughout North America, more than 100 species of bird and mammal are known to eat acorns and for many animals, they are the primary source of nutrition in fall and winter. For example, in many regions of the country, acorn mast makes up 70% of the autumn diet of wild turkeys. In Europe, native Eurasian oaks are widely used to provide forage for livestock, especially pigs. European colonists continued this tradition when they came to the Americas and it is currently experiencing a revival thanks to the superior flavor and nutritional qualities of the resulting pork.

Oak taxonomy is complicated because oaks readily hybridize with other oaks, making classification difficult. However, it’s estimated that there are more than 58 species of native oaks in North America, including the following:

  • Coastal live oak (Quercus agrifolia)
  • White oak (Quercus alba)
  • Scrub oak (Quercus berberidifolia)
  • Swamp white oak (Quercus bicolor)
  • Canyon live oak (Quercus chrysolepis)
  • Scarlet oak (Quercus coccinea)
  • Blue oak (Quercus douglasii)
  • Oregon white oak (Quercus garryana)
  • Gray oak (Quercus grisea)
  • Harvard oak (Quercus harvardii)
  • Shingle oak (Quercus imbricaria)
  • California black oak (Quercus kelloggii)
  • Lacey oak (Quercus laceyi)
  • Turkey oak (Quercus laevis)
  • Valley oak (Quercus lobata)
  • Overcup oak (Quercus lyrata)
  • Bur oak (Quercus macrocarpa)
  • Runner oak (Quercus margarettae)
  • Blackjack oak (Quercus marilandica)
  • Chinkapin oak (Quercus muehlenbergii)
  • Water oak (Quercus nigra)
  • Mexican blue oak (Quercus oblongifloria)
  • Cherrybark oak (Quercus pagoda)
  • Pin oak (Quercus palustris)
  • Willow oak (Quercus phellos)
  • Chestnut oak (Quercus prinus)
  • Red oak (Quercus rubra)
  • Netleaf oak (Quercus rugosa)
  • Shumard’s oak (Quercus shumardii)
  • Bottomland post oak (Quercus similata)
  • Bastard oak (Quercus sinuata)
  • Post oak (Quercus stellata)
  • Texas red oak (Quercus texana)
  • Sonoran scrub oak (Quercus turbinella)
  • Black oak (Quercus velutina)
  • Live oak (Quercus virginiana)
  • Interior live oak (Quercus wislizeni)
Image credit: http://www.flickr.com/photos/randomurl/451703291/