Quercus macrocarpa (Bur oak)
Bur oak (Quercus macrocarpa ) is originally from northeastern America and is considered to be a “settler”. It now grows in Alaska and Canada as well as in the southern United States.
It was first mentioned botanically in 1811.
It is very heat and drought resistant and as a candidate tree against the consequences of global warming in urban areas of Europe (occurs there so far still very rarely).
The burr oak grows up to 50 meters high and reaches trunk girths of up to 3.5 meters. Their growth is relatively slow (30 cm). It is interesting to note that the more northerly the acorns occur, the smaller they become. If they reach diameters of up to 6 cm in southern climes, they are often conspicuously small in the north. The name “Macrocarpa” (= large fruit) refers to the sometimes huge acorns.
The tannic acid content of acorns is relatively low. The smaller the acorns, the sweeter they taste. Thus, the burr oak is one of the few acorns that are edible. They can be easily fried and eaten and are considered a delicacy in some areas of the United States.
The taproot of the Bur oak is considered fast growing and reaches depths of up to 1.5 meters after only two years. The oak species lives up to 400 years. The leaves can grow very large (15 cm long and 5 cm wide) and have a leathery appearance. Due to its very thick bark, this oak species is even (somewhat) resistant to forest fire.
Optimal for the Bur oak are weakly acidic soils. The tree is also considered suitable for urban climates, but grows very sprawling in width. Sunny sites this tree, like most oak species, likes very much, shade sites are not suitable. The tree is sometimes even described as very resistant to the effects of road salt, see e.g. https://www.angelbachtal.de/dr/bur-eiche-grossfruchtigeeiche.
The wood is thick, tough, heavy and durable. It is one of the most valuable barrel and furniture woods. In addition, it is also used in construction for flooring and the like.