For a long time the official state tree of Illinois was “the native oak.” Purists have argued that there is no such tree, that we have many native oaks, and that if our state is going to honor one we ought to designate it properly by both genus and species. Realists have responded that getting the genus right is about as much as we can expect from the Illinois legislature.
All oaks belong to the genus Quercus, and all show a strong tendency to hybridize, making precise identification difficult. Through the years, books on the flora of Chicago have differed on just how many kinds of oaks we have here. The latest edition of Swink and Wilhelm’s Plants of the Chicago Region lists nine full species and three hybrids.
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As partial proof of the intimate connection between oaks and civilization, consider the fact that we could use a tin pot to brew up some slop and drink it to the point of intoxication. But getting plastered in an elegant and civilized way is almost impossible without using oak. Oak barrels are absolutely essential to the creation of Chateau Latour, Nuits-St.-Georges, Maker’s Mark, and grande fine champagne.
Tannic acid is a very effective fungicide. It is the main reason why oak is so durable and resistant to decay.
About 20 percent of France is still covered with forest, and about 25 percent of that is oak woods. The French have been managing their oak woods since about 1000 AD. They use a coppice system that involves making partial cuts that leave scattered trees to serve as seed sources. Oak stumps produce many sprouts that grow into trees, but trees grown from sprouts tend to develop heart rot at an earlier age than trees grown from acorns. So the French system alternates generations. After a cut the relatively fast-growing sprouts provide a new crop in a relatively short time. Then the slower-growing trees produced by acorns become large enough to cut. Since this system has been successful in maintaining both the woods and a continuing yield of timber for about 1,000 years, it seems reasonable to believe that the French are on to something.
The answer may well be blue jays. We know that blue jays cache acorns, and that they often don’t return to eat what they have cached. And that they may carry the nuts for up to a mile before caching them.
We also know that oak woods are very productive when it comes to game animals. Deer, turkey, and quail are all very fond of acorns, and the open character of an oak woods favors these important game animals. And we know that contemporary Native Americans measure the value of an oak woods by the number of game animals it can support–just as medieval Frenchmen calculated the worth of a woods by the number of pigs it could feed.
