City Trees

Kesterson hosted multiple public forums in the planning stages for this project. Native plant enthusiasts came on board early on, and Kesterson welcomed them with open arms. "Once they could tell I was really listening to them, and sincerely appreciated their passion, I was able to lay out how we could incorporate native plants for sure—though the four large 'anchor trees' weren't necessarily going to be native," he says. Kesterson explained how those trees needed to be, above all, tough as nails in terms of site matching. He shared why he was landing on species from New Zealand, Australia, and islands off the coast of California that had the ability to meet all the challenges posed by the strip. The native plant folks stayed involved through planting, and they show an ongoing investment in the success of this project. "That's fantastic—that's what you want as an urban forester," he says. One native tree species was already on site; Kesterson integrated it into the planting scheme: "Some coast live oaks (Quercus agrifolia) have been planted in the strip by squirrels, and those trees tend to stay smaller than usual because of the wind and limited soil conditions. Coast live oak is a desirable species for us at any height, so we kept those trees." The four anchor tree species were the first to be planted—101 of them, with each species spaced every 45-50 feet (14-15 m) along the entire stretch. Note that the trees won't reach "height in ideal conditions" here—ultimate height being difficult to predict in such a specifically challenging site. The four anchors are: • water gum (Tristaniopsis laurina) – a slow-growing, compact tree native to Australia that can reach 15-30 feet (4.6-9.1 m) tall in ideal conditions. • New Zealand Christmas tree/Pōhutukawa (Metrosideros excelsa) – a coastal evergreen, reaching up to 80 feet (24 m) in ideal conditions (but generally stays under 30 feet in California) that is revered by the Māori people. • island oak (Quercus tomentella) – a fast- growing and trouble-free species native to six islands off the coast of California, it can reach 60 feet (18 m) in ideal conditions. • red-flowering gum (Eucalyptus fici- folia) – from Western Australia, it prefers low-fertility and sandy soils and can reach 33 feet (10 m) in height in cultivation. The four species were planted by contractors who also did the site preparation and irrigation installation. "After the anchor trees were planted, we came back and filled in this freeway site with a diverse collection of a total of 900 small trees, shrubs, flowering plants, and grasses that were site-appropriate," Kesterson says. The Google Map showing the macro-view of the San Francisco Bay, I-580, and Aquatic Park. Google Map closeup of the Bay, I-580, and a section of the Aquatic Park lagoon. The mile-long (1.6-km-long) "green row" in newly created 6-foot-wide (1.8-m-wide) tree wells lies between, and runs parallel to, I-580 and West Bolivar Drive. 32 CityTREES

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