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The new tree planted at Malcolm X School last month is an alien here, but not an invasive species nor as troublesome as, say, blue gum eucalyptus; I’d call it a perfectly respectable city tree. It’s a northern red oak, native to the eastern part of the continent, and it will pay its biological dues here in due time, when it starts bearing acorns. There might be an organism or three willing to dine on its leaves, too. 

Our native oaks, especially our various species of evergreen live oaks, support lots of wildlife. That’s one reason people are so worried about Sudden Oak Death Syndrome—live oaks are keystone species in their ecosystems, supporting and sheltering a host of other organisms, some of whom support still more organisms and so on. That’s also true of many of the other plants also suffering from SODS. Our native deciduous oaks, like black oak, are also at risk and also nurture lots of other species. Another susceptible Californian, Shreve’s oak is a fairly close relative of the red oak at Malcolm X. It remains to be seen whether the so-named red oaks can die of it too; I’m crossing my fingers. 

The susceptibility of various plants to SODS is still a puzzle, and it’s possible that resistance to it is more a matter of individual plants than of species—that some live oaks, some black oaks, some tanoaks (not a “true” oak, but so far the main casualty) and so forth will be able to survive unscathed. The SODS organism has turned up in the eastern United States, though, so we might have a chance to find out. Our urban trees won’t be the only guinea pigs (to mash a metaphor) that get exposed to the stuff. 

(The stuff is Phytophthora ramorum, a “water mold”—not exactly a mold or fungus, but another clade entirely. The more you learn about biology, the weirder the world becomes.) 

Oaks might have the tools to cope. They’ve been fighting via chemical warfare for a long time. They, like tanoaks, are a major source of the tannin that we’ve used for centuries in processing things like leather; the trees “use” it and other chemicals to reduce their appeal to various bugs and other animals. Meanwhile, the animals, especially those bugs, have been evolving tolerances for the chemicals, and so on, ‘round and ‘round. The bigger critters, including us, have been working out ways to eat the nutritious acorns that the oaks make to feed the embryos tucked into them. 

The way we do it is often by food processing. Some oaks’ acorns reputedly are edible without it, but most require repeated leaching to get rid of nasty-tasting or even toxic stuff. After that, the acorn meal is high in protein and fats, and, in the right hands, even tasty. I’d put it somewhere between fufu and poi. 

People are fond of oaks, and love to name things and places for them. An oak woodland is a distinctive space. Oaks tend toward rounded forms and in great age they assume that squiggly branch structure that can make a menacing figure in dim light, all elbows and grimaces. They’re usually long-lived, with strong wood and wide branch angles, which makes for “champion” trees. An oak standing alone in a field has a great deal of presence, and a double file of middle-aged oaks running down a broad street gives us an instantly embraced, gracious feeling. Look at California Street north of Dwight for an example. 

Possibly their only vice—live and deciduous oaks both—is that they have inconspicuous little flowers that cast lots of pollen on the wind, making them prime allergens wherever they grow. We’ve just passed oak-pollen season here, and I’m relieved. 

Other than that, they tend to be good citizens, and the genus has enough species with different characters to fit into a number of urban niches. Besides, when they do die or need to be taken down, their wood makes decent lumber—and there are urban sawmills to use it. I’ll talk more about those as I tell more urban oak stories in the next few columns.