The American chestnut (Castanea dentata) is a large, fast-growing deciduous tree of the beech family native to eastern North America.

[13] American chestnuts are also susceptible to ink disease, particularly in the southern part of its native range; this likely contributed to the devastation of the species.

Japanese chestnut was inadvertently introduced into the United States by Thomas Hogg in 1876 and planted on the property of S. B. Parsons in Flushing, New York.

[29] The chestnut is monoecious, and usually protandrous producing many small, pale green (nearly white) male flowers found tightly occurring along 6 to 8 inch long catkins.

[35] American chestnut burrs often open while still attached to the tree, around the time of the first frost in autumn, with the nuts then falling to the ground.

The other lineage of American Chestnut shows a gradual loss of genetic diversity along a Northward vector, indicating possible expansion of range following the most recent Glacial Maximum during the Wisconsin glaciation.

[45] The surviving trees are "frozen in time" with shoots re-sprouting from survivor rootstock but almost entirely undergoing blight-induced dieback without producing chestnuts.

[46] The pre-blight distribution of the American chestnut was restricted to moist, but well-drained, steep slopes with acid loam soils.

Along the Blue Ridge Mountains of North Carolina, the American chestnut dominated the area above the range of the Eastern hemlock and below 1,500 meters.

[51][48] The tree's abundance was due to a combination of rapid growth, relative fire resistance, and a large annual nut crop, in comparison to oaks, which do not reliably produce sizable numbers of acorns every year.

Historically, the mean fire return interval was 20 years or less in chestnut-predominant ecologies, with a forest stand pattern that was more open than is currently the case.

[52] The American chestnut was an important tree for wildlife, providing much of the fall mast for species such as white-tailed deer, wild turkey, Allegheny woodrat and (prior to its extinction) the passenger pigeon.

The American chestnut also contains more nitrogen, phosphorus, potassium and magnesium in its leaves than other trees that share its habitat, so they return more nutrients to the soil which helps with the growth of other plants, animals, and microorganisms.

[53] The American chestnut is preferred by some avian seed hoarders, and was particularly important as a food source during years where the oak mast failed.

While the Columbian exchange moved valuable crops between the Americas, Europe and Asia, there was also a downside, as the rapid introduction of invasive and unfamiliar pathogens resulted in serious damage or extinction of some host species.

[60][61]: 145 [62] The airborne bark fungus spread 50 mi (80 km) a year and in a few decades girdled and killed more than three billion American chestnut trees.

Salvage logging during the early years of the blight may have unwittingly destroyed trees that had high levels of resistance to the disease and thus aggravated the calamity.

[65] The high density of American chestnuts within its range and the lack of natural immunity allowed the blight to spread quickly and cause infection and die-off in nearly every tree exposed.

[77] Although large trees are currently rare east of the Mississippi River, they exist in pockets in the blight-free West, where the habitat was agreeable for planting: settlers took seeds of American chestnut with them in the 19th century.

Huge planted chestnut trees can be found in Sherwood, Oregon,[78] as the Mediterranean climate of the West Coast discourages the fungus, which relies on hot, humid summer weather.

[82] Researchers at the State University of New York College of Environmental Science and Forestry (SUNY ESF) have developed the Darling 58 chestnut cultivar.

[90] Transgenic modification of C. dentata with the Cast_Gnk2-like gene may provide a mechanism for developing American chestnut trees resistant to Phytophthora cinnamomi.

[91] The American Chestnut Research and Restoration Project at SUNY-ESF is not pursuing intellectual property (IP) protection through patents.

Griffin, who has been involved with American chestnut restoration for many years,[102] developed a scale for assessing levels of blight resistance, which made it possible to make selections scientifically.

Grafts from large survivors of the blight epidemic were evaluated following inoculations, and controlled crosses among resistant American chestnut trees were made beginning in 1980.

[8][10][107] Burnham, a professor emeritus in agronomy and plant genetics who was considered one of the pioneers of maize genetics,[108] realized that experiments conducted by the USDA to cross-breed American chestnuts with European and Asian chestnuts erroneously assumed that a large number of genes were responsible for blight resistance, while it is currently believed the number of responsible genes is low.

The reduced ability of the fungus to cause disease allowed the European chestnut to regenerate, creating large stands of trees.

[125] The nuts were once an important economic resource in North America, being sold on the streets of towns and cities, as they sometimes still are during the Christmas season (usually said to be "roasting on an open fire" because their smell is readily identifiable many blocks away).

[20] Being rich in tannins, the wood was highly resistant to decay and therefore used for a variety of purposes, including furniture, split-rail fences, shingles, home construction, flooring, piers, plywood, paper pulp, and telephone poles.

[3] Although larger trees are no longer available for milling, much chestnut wood has been reclaimed from historic barns to be refashioned into furniture and other items.