Here on the north coast, Phytophthora ramorum kills tanoaks almost exclusively. We don’t have coast live oaks, and our California black oak population has steadily been decreasing because of land-use changes accompanied by corresponding changes in forest cover (a topic for another blog entry sometime). This year I’ve had the opportunity to see more majestic tanoaks than usual because of some projects we’ve been involved in—projects to save large tanoaks by applying a systemic fungicide that prevents infection by P. ramorum.

What we often see in our part of the world are dense thickets of small tanoaks, usually growing in clumps where it is obvious that all the trunks sprouted from the same mass of root tissue. Often these clumps are legacies of cutting in the past, either to clear land or to harvest the trees for the tannin in their bark (most of this occurred around the turn of the 20^th century). When tanoaks are cut, the mass of budding root tissue at the base of the tree (called the “burl”) is stimulated to produce a multitude of new sprouts to replace the lost trunk. Although they still have the old root system, these areas of young, dense tanoaks haven’t established their dominance in the forest yet with expansive crowns, so they usually compete for forest floor space with lots of huckleberry and other shrubs.

Here’s an example:

However, here and there on the landscape you can find some groves of “old-growth” tanoak. These specimens easily compete for beauty with any of the true oaks California is famous for. Native Americans valued these groves for their abilities to produce vast quantities of acorns and took care of them to keep them accessible and healthy. Here's a big one:

There’s a common misconception out there that foresters and land managers don’t value tanoak or think of it as a “weed” tree because it lacks economic value in the wood markets of today. It is true that land managers sometimes try to discourage tanoak growth in certain stands of trees so that they can reforest those areas with conifers such as Douglas-fir. But this doesn’t mean that they always think of tanoak as a weed. In these cases, as with all land management activities, it’s important to think about management goals for the land and how best to work with the land to enhance an abundance of values.

 In many cases, by attempting to control tanoak, foresters are trying to return to its historic condition land that was cut over years ago and left without any attempt to replant the Douglas-firs that originally grew there. In other cases, the soils, topography, and moisture conditions on the site are perfect for growing Douglas-firs, so the property foresters are trying to maximize the capabilities of that land to grow what is marketable. Tanoak is a beautiful wood with a lot of character, and if people come to value wood with these qualities, industrial forestry attention could shift away from its strong focus on Douglas-fir.

This also fits in with a larger societal picture of trying to take responsibility for our own needs for wood in California by growing and buying local rather than importing all our wood from places like Canada and Brazil that lack California’s stringent environmental regulations (check out this report--thanks to Yana Valachovic for the reference). As we try to puzzle out all the pieces of this complex picture by fitting needs for wood products into just-as-compelling needs for ecosystem stability and connectivity, aesthetic beauty, and wildlife habitat, we come to realize that tanoak is an important piece of the puzzle—and we see the damage that non-native, invasive species can potentially do when they rob us of such pieces.