Trees

There was a lot of talk in the local blogosphere a month or two back about the piss-poor job being done pruning Durham's beautiful willow oaks by a contractor hired by Duke Energy. (See here, and here, for example, as well as this news story.)

Turns out that's not the only problem with the willow oaks. Seems they were all planted at around the same time in the 1930s, and they're all reaching the end of their lifespans around the same time. (Gary indicates that they're only middle aged, but i think that even without the pruning, the stress of being planted in streetside right-of-ways has got to cut quite a bit off the useful life of a tree.) As i recall, the entire block across the street from Club Blvd. Elementary had its willow oaks removed in the late 90s as they were deemed to unhealthy and dangerous to leave standing.

Josh Rose, a biologist and former Old North Durham resident who lives now in Texas but still stays in touch, doesn't dispute that a lot of these trees are going to need replacing. But he sees some problems with the approach which Durham officials are quoted as presenting.

About the Willow Oak replacement discussed in the article, it
is disturbing to see that nearly all of the proposed smaller replacement trees, the ones for areas with powerlines (which covers a lot of Durham streets), are non-native. Trident Maple, Hedge Maple, Paperbark Maple, and Crepe Myrtle are all native to Asia. You might think that we would have learned to quit planting non-native trees in the US after we introduced Dutch Elm Disease and Chestnut Blight and wiped out what had been two dominant trees from eastern US forests and neighborhoods, but apparently not, so now we have Dogwood Anthracnose, Hemlock Wooly Adelgid, Oak Wasting Disease, Emerald Ash Borer...

The other issue with non-native trees is insect diversity. Native trees, including the Willow Oaks, have leaves edible to numerous caterpillars, beetles, and other insects. Native flowering trees, like redbuds and dogwoods, attract all sorts of pollinators like butterflies, bees, flies, and more. Not only do the butterflies themselves lend color to the neighborhood, but the other, less visible insects are food for songbirds like warblers, vireos, flycatchers, chickadees, nuthatches, and many others. You will very rarely see birds like these in a Crepe Myrtle or other non-native, because there is virtually nothing for them to eat. You might see the occasional mockingbird or cardinal there, not much else.

Seems like it shouldn't be that much harder to make smart decisions regarding our next generation of tree plantings, rather than short-sighted ones. Josh continues:

Anyone in Old North Durham, Watts-Hillandale, or other neighborhoods (and this includes virtually all of Durham's urban neighborhoods, including Trinity Park, Old West Durham, Northgate Park, Duke Park, Cleveland-Holloway, et al) with aging trees needing replacement, if you would like to see as many or more birds and butterflies around your yards, convince your city to plant only tree species native to the US. Note that even some commonly used dogwoods and redbuds are Asian (hence the Dogwood Anthracnose, a fungus carried by Asian dogwoods that threatens our native species), so make sure to specifically ask for Cornus florida and Cercis canadensis. Some other natives, probably not carried by
the city arborists, but available from some local nurseries, and which tend to stay small enough to not threaten powerlines, include Fringe-tree (Chionanthus virginicus), Parsley Hawthorn (Crataegus marshallii), Persimmon (Diospyros virginiana), Sourwood (Oxydendrum arboreum), Fevertree (Pinckeya bracteata), and various species of Buckeye (Aesculus spp.). I'm sure there are others. Of course, in areas without powerlines, the possibilities are nearly endless, including Beech, Tulip Poplar, Sycamore, Red Cedar, various Birches, and many more...

(Neighborhoods listed in italics added to Josh's letter.)

All of my experiences with Durham's Department of Urban forestry have been overwhelmingly positive, and i can't imagine that the smart and dedicated people there haven't thought this through. But still, it wouldn't hurt to drop them a line and ask them to consider a program of replacing these willow oaks with native trees for the reasons Josh mentions. We'd like Durham to be even more livable for those who will be here long after we're gone.