The nuts are used by squirrels as a food source, however, and native California tribes cooked and leached the nuts to remove the poison before eating them, though most Eastern tribes and early colonists avoided them in favor of safer and tastier nuts. The beautiful nuts are also regarded by many people as a good luck charm.

Buckeyes make attractive ornamental trees in areas where livestock poisoning is not a serious risk. The Ohio buckeye (Aesculus glabra) is the state tree of Ohio.

Native buckeye species include:

• California buckeye (Aesculus californica)
• Yellow buckeye (Aesculus flava)
• Ohio buckeye (Aesculus glabra)
• Bottlebrush buckeye (Aesculus parviflora)
• Red buckeye (Aesculus pavia)
• Painted buckeye (Aesculus sylvatica)

In addition to being an important timber tree thanks to the quality of its wood, the American beech also produces edible nuts which are an important source of food for many wildlife species, including wild turkey, pheasant, ruffed grouse, whitetail deer, squirrels, and many more. It is believed that beech nuts were one of the primary foods of the now-extinct passenger pigeon, and that one of the factors in the birds’ extinction was the logging of many native beech forests in the 19th century. The nuts are also used as livestock feed, particularly for pigs and turkeys.

Beechnuts are also edible by humans, but they are not as widely used as the nuts of many other hard mast producing trees because the nuts are difficult to remove from the shells.

Another notable feature of the American beech is its unusually smooth bark, which makes it a common victim of graffiti artists. The most famous example was a now-authenticated carving found on a beech tree in Kentucky that read “D. Boone kilt a bar 1803.” The section of tree trunk can now be viewed at the Filson Historical Society in Louisville.

In many parts of its range, the American beech is threatened by Beech Bark Disease (BBD), a fungus accidentally introduced to North America from Eurasia in the late 19th century. Though the effects have been less dramatic than the near-total annihilation of the American Chestnut by Chestnut blight, which began around the same time, BBD is still a major ecological threat and efforts are underway to breed resistant trees and find other ways of controlling and containing the disease.

Although commercially available hazelnuts are derived from the Eurasian native Common Hazel (Corylus avellana), there are two native North American hazelnut species, the American Hazelnut (Corylus americana) and the Beaked Hazelnut (Corylus cornuta), which are also edible and delicious, but less suited for cultivation due to their lower productivity and smaller nut. Because the delicate Common Hazel can only be grown domestically in the Pacific Northwest, some American plant breeders have also crossed European and American hazelnut species in an attempt to produce a hazelnut combining the higher nut quality and quantity of the European species with the greater hardiness and disease resistance of the native American species, and some of these hybrids are now available from nurseries.

In addition to their widespread use by humans for praline, Nutella, candies, and many other delicious treats, hazelnuts are also an excellent wildlife plant. Among the animals that enjoy the nuts are wild turkeys, pheasants, whitetail deer, squirrels, and woodpeckers, as well as domestic pigs and some poultry. The catkins are enjoyed by ruffed grouse and turkey.

Hazelnuts provide good cover for birds and are excellent additions to hedgerows, windbreaks, and woodlots, yet ornamental enough to use in home landscapes.

By far the most common walnut species in North America is the Black Walnut (Juglans nigra), which is native to most of the Eastern half of the United States and Canada, from Quebec to Florida and the Atlantic coast to the eastern edge of the Great Plains.

The Butternut (Juglans cinerea) is another of the most common native walnuts. It is even hardier than the Black Walnut and some people prefer its flavor.

Other native walnuts include:

• Southern California walnut (Juglans californica)
• Northern California walnut (Juglans hindsii)
• Arizona walnut (Juglans major)
• Little walnut (Juglans microcarpa)

Black walnuts make attractive but somewhat troublesome additions to the woodlot or home landscape. The leaves, roots, husks, and woody parts of the tree contain a toxin called juglone that is harmful to many other plant species, including many common garden plants. The toxicity may spread well beyond the tree’s drip-line and last in the soil for years after the tree dies or is removed. In nature, the toxicity helps protect the tree’s “territory” and ensure that it gets enough sunlight. In the garden or woodlot, it can be a real bother. The Michigan State University Department of Horticulture offers a substantial list of plants that can and cannot be grown near walnuts.

Horse and dog owners should also be wary of planting black walnuts. Dogs become ill after eating the nut husks (clean up debris regularly to prevent this) and horses can develop respiratory problems from black walnut pollen and leaves, and laminitis if bedded down in wood shavings that contain 20% or more black walnut.

However, large pigs will eat walnuts eagerly with no ill effects, as will smaller pigs and poultry if the nuts are broken open for them.

Juglans regia, variously known as the English, Persian, or Common Walnut, is a non-native walnut that can be successfully grown in some regions of North America. It is hardy to zone 5 and produces juglone in much smaller quantities than Black Walnuts.

The chestnuts were reliable yearly mast producers and were one of the most important food sources for dozens of different wildlife species, from black bears to passenger pigeons, as well as domestic livestock. The nuts were also considered a delicacy by humans, though ironically the line that immortalized the delicious nut “chestnuts roasting on an open fire” was written in the 40′s when the chestnuts were already nearly gone.

The American chestnut was an important timber tree – lightweight, easily worked, and extremely resistant to rot – and the combination of nut collecting and lumber production made up a major part of the rural economy of the region.

Then, in 1904, a few trees at the Bronx Zoo in New York began to die. The culprit was chestnut blight accidentally introduced into New York on some infected Chinese Chestnuts, and the blight spread like wildfire through the eastern woodlands, killing an estimated 4 billion chestnut trees and changing the ecology of the region forever. By 1950, the beautiful American Chestnut was nearly extinct, surviving only in a few scattered individuals and patches where the blight had been less virulent, mostly outside the chestnut’s native range. Sprouts also emerge sometimes from the surviving roots of once mighty trees killed by the blight, but these are becoming less frequent as time goes on and they rarely survive longer than 15 years before succumbing to the blight themselves.

A number of groups, including the American Chestnut Foundation, the American Chestnut Cooperators Foundation, the US Forest Service’s American Chestnut Restoration Project, the Canadian Chestnut Council, and others are working to develop blight-resistant strains of the American Chestnut by crossing and backcrossing surviving trees and sprouts with Chinese Chestnuts (which evolved with the blight and are highly resistant to it). Early research into genetic modification to impart blight resistance has also taken place.

Today, the inferior Asian and European species are the primary source of chestnuts in the United States and they can be a useful addition to a stand of native mast-producing trees. It may also be possible to become a cooperating grower of pure or hybrid American Chestnuts. One of the best and most popular hybrid AmericanxChinese chestnuts is the Dunstan Chestnut, developed by Dr. Robert Dunstan, which produces large, easy to peel nuts and is blight resistant.

Hickory nuts are edible by humans as well as wildlife. The best-tasting hickory nuts are considered to be from the Shagbark hickory (Carya ovata), the Shellbark hickory (Carya laciniosa), and the pecan (Carya illinoinensis).

There are more than 20 hickory species native to North America, including the following:

• Mockernut hickory (Carya alba)
• Water hickory (Carya aquatica)
• Bitternut hickory (Carya cordiformis)
• Scrub hickory (Carya floridana)
• Pignut hickory (Carya glabra)
• Pecan (Carya illinoinensis)
• Shellbark hickory (Carya laciniosa)
• Nutmeg hickory (Carya myristiciformis)
• Red hickory (Carya ovalis)
• Shagbark hickory (Carya ovata)
• Sand hickory (Carya pallida)
• Black hickory (Carya texana)

Oaks also played an especially important role in the forests of California, which is 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.

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.

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)