Sunday, January 13, 2008

White oak

Is this the tree that launched a thousand ships? It is indeed. White oak, an American native, reached the pinnacle of its maritime glory during the War of 1812. The white oak planks of the U.S.S. Constitution repelled British cannonballs so well that the ship became known as "Old Ironsides". After a few encounters with the Constitution and its sister ship, the British admiralty forbade its frigates from engaging the American 44-gun frigates in single combat.

William Bryant Logan relates the story of the U.S.S. Constitution in his 2005 book Oak: The Frame of Civilization.(1) Mr. Logan claims a central role for oak (not just white oak) in human development. He reviews evidence that early man was dependent on acorns as a staple food and presents a map showing the distribution of oak trees to be conterminous with the locations of settled civilizations in the northern hemisphere. You already knew, no doubt, that oak made durable furniture, sturdy ships, and watertight barrels. Did you also know that oak galls made ink and that oak tannins tanned leather? Did you know that oak was used in shipbuilding even before it helped Jason and the Argonauts find the golden fleece? Mr. Logan lays out all these details of mankind's reliance on oak in his informative book.

Oak is a complicated genus. There are as few as 250 or as many as 600 species of oak, depending on whose classification you accept. To complicate life, many oak species interbreed with one another. Oaks are conventionally divided into two groups: the white oak group with white oak as its most typical species, and the red oak group with red oak as its exemplar. The white oak group has leaves and leaf lobes that are rounded. The red oak group has leaves and lobes that end in points with bristle tips.

Acorns of the white oak group mature in one growing season; the reds require two seasons. White oak group acorns have a lower tannin content than the reds. The tannin content difference represents divergent survival "strategies". Tannins protect acorns by imparting a bitter taste and by interfering with animals' protein digestion. Squirrels are quite tuned into differences in tannin content. They eat white oak acorns immediately and bury reds. With less tannin protection, acorns of the white oak group are obliged to begin to grow shortly after contacting the ground in the fall. If the squirrels don't eat the white oak acorns immediately, it's too late. The squirrels can permit the very tannic and slower-to-sprout acorns of the red oak group to marinate underground during the winter.(2) People can eat acorns any time they care to do so by leeching out the tannins with water. Recipes abound on the Internet.

The grand white oak at 1310 Central Avenue pictured in leaf at the top of the page and leafless below is 5 or 6 feet in diameter. Surely well over a century old. Sadly, one sees limbs lopped at the property line on the left side. (There ought to be a law.) The tree illustrates the characteristic white oak habit and the vast spread of a mature white oak's limbs. The spread limits the species' use as a curbside planting.

Another fine white oak is at 705 Ravine Road.

Most white oaks are easily recognizable in the winter by their blotchy bark. The blotchiness is caused by an apparently harmless fungal infestation.

Xavier Canela sends word from Spain that he has a blog about the trees of Barcelona: The blog is in Catalan. If you can read one of the Romance languages, you can understand it without much difficulty. One of his posts regards Pinus pinea, the source of most of the pine nuts on the market and probably best known as the pines of Rome. (The pines of Rome, it turns out, are natives of Iberia.)
(1) Oak: The Frame of Civilization, William Bryant Logan, W.W. Norton and Company 2005, pp. 230-249.

(2) A Field Guide to Eastern Forests, John Kricher and Gordon Morrison, Houghton Mifflin 1998, p. 84.

Copyright Gregory Palermo


Dan said...

Interesting post about the White Oak. Regarding the Pinus pinea tree, I've always referred to it as the "Stone Pine". I've got some great pictures of the pine nuts from this tree in Spain on my tree-species blog.

Gregory Palermo said...

Thank you. I would be very interested to see your tree-species blog. What is the address?

Dan said...

Ruth Sykes said...

What do the large orange 'X'S indicate on several trees along kensignton Ave? I am praying that it does not mean they are to be cut down! Several do need triming, but not all. Have you any idea what this is about?