New City Tree Plan: Urban Forest in Flux

By Doug Hayward
Alameda, CA (February 12, 2009)- Not a single gorgeous liquid-ambar on Gibbons Drive or anywhere else, not a camphor on Santa Clara Avenue, not one Modesto or Rayburn ash remaining on city streets, nor a single oak, though they once blanketed local land. That’s the future as the city puts final touches on its new plan for street trees.

Just a few Alamedans concerned about the status of their city’s 15,000 or so “street” trees recently sat through a two-hour Master Tree Plan Update derived from a 51-page document called the “Tree Inventory Results & City-wide Planting Palette.”
Nothing like this has been produced for the Master Tree Plan since 1989, but exactly when and how the new update findings may be implemented is problematic at this time. That’s due to the general economy and budget constraints, according to Deputy Public Works Director/Engineer Barbara Hawkins. But, she emphasized, a canopy of beautiful trees not only makes Alameda a better place to live, but adds substantially to property values.
With public input, the current information will be part of an upcoming proposed tree program to be put before the City Council.
Charlie Lanfranco, one of the study presenters at City Hall, said of the report, “As far as our research can tell, there’s no other city in North America that has a tree matrix like this one that shows in one location all these things.”
As an associate with Tanaka Design Group of San Francisco, he discussed aspects of the now-compiled results of the five-month city tree inventory by his firm under contract to the city last year. His co-presenter, Melanie Gentles, a consultant who is campus arborist at University of California Davis, explained scientific points of the study. Those included recommendations for existing street tree care here, as well as new tree choices plus planting and growth maintenance.
One such vital recommendation in particular, she said, is that of selecting contractors who can prune to high professional standards. As part of the inventory, the Tanaka team is also identifying suitable strategic bare spots not now occupied by trees.
Both speakers recounted how the inventory effort involved inspections one-by-one of almost 12,000 of the existing city “street trees.” They detailed the hands-on evaluations of such factors as each tree’s physical condition and its overall fit in Alameda’s “urban forest.” Among bottom-line questions of the study are whether certain trees should stay or go – and if the latter, what kind should replace them.
Issues at hand include whether certain trees do more harm than good in terms of their impacts on other trees, buildings, sidewalks and streets, overhead utility lines and so forth.
Trunk and root-ball size, branch spread, leaf and seed debris, tree height and more are also considerations. Even some entire species of trees are in question here as elsewhere, such as oaks because of their susceptibility to Sudden Death Oak Disease.
Among trees here found wanting and recommended for removal are the city’s 337 liquidambars, including those famously lining Gibbons Drive.
Although beautiful, unfortunately a serious problem is the roots of the Liquidambar styraciflua (also known as American sweetgum and redgum).
Said roots wreak havoc by growing under and lifting sidewalks, and breaking curbs and pavement. The plan is not to rip out all liquid mbars at once and replace them, but to do so gradually over time. The same applies to all other problem trees in Alameda. None is recommended for abrupt eradication or decimation, the Tanaka report stresses.
Another case is the 290 camphor tree surveyed throughout the city, but mostly on Santa Clara Avenue. Once again, this one, properly known as the Cin-namomum camphora, is a root bully. That offsets the loveliness of its leaves, and the charm of its seedpods, which look like upside-down ice cream cones. Cracked sidewalks and streets are both hazardous and expensive to fix.
Yet another is the ash, of which 825 were surveyed, most of them “Raywood” and “Modesto” varieties. Lining Broadway and High Streets, these members of the Fraxinus family are subject to severe decay and experience weak branch attachments. Yet their small leaves are attractive and their seeds are fascinating, described as “keys” or “helicopter seeds.”
A beetle known as the ash borer is also killing these trees wholesale in some U.S. areas.
And the list goes on and on, street by street, neighborhood by neighborhood. Still, trees are in the interests of the residents of Alameda. As the city Web site puts it: “The leafy canopies of trees that line the city’s streets provide many benefits to the community: shade, screening, natural beauty, environmental benefits, as well as food and shelter for birds and animals. Healthy, well-maintained trees provide an improved quality of life and economic benefits to the community through enhanced property values.”
While the inventory results and other documents are to be published as soon as possible online by the city Department of Public Works on its section of the city Web site, no one can say exactly when.
Related Resources:
Alameda Sun- New City Tree Plan: Urban Forest in Flux