City Trees

What are the unique pleasures of urban forestry in Providence? DS: We have an engaged interested citizenry and a lot of tree lovers here. The Providence Neighborhood Planting Program (PNPP) is fabulous and a good model for other cities. PNPP requires neighborhood groups to apply for trees in their neighborhood. The City prepares the site and soil, including cutting concrete when necessary, and we select and bring the trees and provide a planting and aftercare demonstration. PNPP organizes folks to come out and plant on Saturdays in April and October; each year, 500 of the total 650 trees planted annually get planted with these volunteers. This approach gives people a stake in the trees' existence. Then PNPP volunteers keep the trees mulched and watered. We are fortunate in Providence to have not one, but two private endowments supporting our tree program. First, the Mary Elizabeth Sharpe PNPP Fund of the Rhode Island Foundation is a public-pri- vate partnership in which the City matches the Fund's contributions each year for tree planting. Second is the Helen Walker Raleigh Tree Care Trust that's set up for tree care; thanks to the Raleigh Trust matching City funds, we have been able to institute a block-pruning program on a ten- year cycle. We are fortunate that Mayor Elorza's administration realized how important systematic pruning is, and provided the match funding. We're in year three of the first cycle and it's allowed us to triple the number of trees we prune each year, and to shift ever more towards proactive manage- ment and away from reactive service requests. Another thing we're really proud of is our Providence Forestry Division staff: our tree trimmers, foremen, tree inspector, and forestry clerk. Our arborists have high levels of skill and training and really know what they are doing. Most of the pruning we do, including the ten-year-cycle pruning, is done in-house and allows us to be responsive to the community. Do you plant B&B, bare root, or container? DS: I'm a big advocate for bare root and we did try it for several years, but we found that containerized stock works best for our volunteers and our planting schedule of multiple Saturdays spread throughout the month—the container stock can hold over better than bare root trees could. To combat the risk of buried root collars, we contract with a nursery and work closely with them to grow our container stock to size; I select and tag the material myself. Many species do well in containers, and we find that some species like tupelo (Nyssa sylvatica) are actually better off containerized, because they resent any disrup- tion of their root systems before you plant them. There are some exceptions. We do have to bring in B&B ginkgos (Ginkgo biloba) because they're too small in containers, and Japanese scholar tree (Styphnolobium japonicum) because we just can't source that species in containers. The coni- fers that we plant in parks we buy in B&B. What tree species are your best performers? DS: Oaks in general do really well here in terms of the size they get and what they offer in eco- system services. Red oak (Quercus rubra) and pin oak (Q. palustris) are especially thriving, and one of our most historic streets is beau- tifully lined with London plane trees. We've diversified our inventory significantly since 1988 when a tree inventory found that 47% of the City's street trees were Norway maple (Acer plata- noides) and that 60% of the trees were in the maple genus. By 2006, the Norway maple percentage was down to 18%. We recently completed a comprehen- sive street tree inventory and are going to be running the numbers soon; it will be interesting to see how much lower the percentage of Norway maples is now. One tree that we discovered does beautifully here with hardly any care is Korean mountain ash (Sorbus alnifolia). Armstrong maples (A. freemanii 'Armstrong') do well in our narrower commercial district planting spaces, as does the upright Zelkova 'Musashino'. Persian parrotia (Parrotia persica) per- forms well in small spaces here, too. Near parks and natural areas, we plant native species like hackberry (Celtis occidentalis) and red maple (A. rubrum). >> 24 CityTREES PNPP organizes volunteers to plant on Saturdays in April and October. Each year, 500 of the total 650 trees are planted by volunteers.

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