Short answers, pulled from the story.
There are approximately 500 extant species of oak in the genus Quercus. They range across the Northern Hemisphere from cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the highest concentration, with about 160 species in Mexico alone.
Quercus alba can live up to 600 years. The Granit oak in Bulgaria, a Quercus robur specimen, has an estimated age of 1,637 years, making it the oldest oak in Europe. A live oak on the reservation of the Pechanga Band of Indians in California is at least 1,000 years old and may be as much as 2,000 years old.
Oaks are keystone species in habitats ranging from Mediterranean semi-desert to subtropical rainforest. They support more than 950 species of caterpillars and host hundreds of species of insects, fungi, and gall communities. Several species of truffle, including the black Périgord truffle and the white Piedmont truffle, form symbiotic relationships with oak roots.
An estimated 31% of the world's oak species are threatened with extinction, and 41% are considered to be of conservation concern. As of 2020, China has the highest number of threatened oak species at 36, followed by Mexico with 32, Vietnam with 20, and the United States with 16.
Oak barrels contribute flavors, colors, and aromas to wine, whisky, sherry, and brandy during the aging process. French oak from Quercus robur and Quercus petraea is chosen for the finest wines because it gives greater refinement. American oak produces a more powerful bouquet and better resistance to aging, and barrels are often charred before use to enhance flavor.
The oak was sacred to thunder gods across prehistoric Indo-European cultures, including Zeus in Greek mythology, Thor in Norse tradition, and Perkūnas in Baltic belief. The oracle at Dodona in Epirus centered on a sacred oak. The oak is the national tree of more than a dozen countries, including the United States, Germany, France, and Poland, and is the current symbol of the Conservative Party in the United Kingdom.