Who would think a desert city such as Phoenix would have an urban forestry department? Recently I heard Phoenix’s head forester speak about the city’s lofty goals for planting more trees and providing shade coverage in urban settings as well as parks and neighborhoods. In fact the city’s target is 25% shade coverage by the year 2030.
As the guy in charge of all the city’s trees, Richard Adkins’s days are full of calls from people who have issues with those trees. Yes folks, over time, trees get big. Uppermost branches encroach on power lines or block billboards, lateral branches impede sidewalks and truck traffic. Storms or old age may topple trees that have lived for generations.
As Adkins will tell you, most problem trees are victims of poor planning. Part of his job is working with urban planners and developers to plan for sensible tree planting. How often do you see twenty foot trees growing from a four foot square cut-out in the middle of an asphalt parking lot? The root system of a healthy tree is equal to the size of the tree’s crown. Adkins argues that any good-sized tree should be granted 400 square feet of open space for its roots. This means a planting area that won’t be compacted by sidewalks or covered with pavement. New technology for “floating” sidewalks and permeable pavement protects tree roots and allows rainfall to benefit trees.
Adkins advocates planting “nodes”, or clusters of trees with shrubs beneath them. Rain water shunted to the area benefits the plants while they in turn help with runoff issues. A few large trees, properly planted, stem the slashing destruction of a big storm rather than becoming victims. A guild of trees and other plants is much more sustainable than a straight line of trees with insubstantial roots growing in heavily paved areas.
It’s a no brainer that trees provide tremendous benefits. Adkins confirmed that trees are proven to soothe and cool an urban population. Yet trees also provide services to the city such as improvements in air quality, storm water maintenance, reductions in energy costs and increases in property values.
Trees absorb vehicle emissions as well as particulates from the air. In storm events leaves break up the downpour, while roots prevent erosion and soak up excess water. Adkins pointed out that outdoor malls with tree-lined streets and walkways offer a pleasing ambiance that draws customers who spend money, assisting the business environment of those areas.
Financial models indicate a return on investment of $2.23 per dollar spent on trees in the city. Property values increase 10-12% with well maintained trees out front. Tools such as the Tree Benefits Calculator and i-Tree software document the financial benefit of planting a tree in a specific location.
The city periodically offers Homeowner Tree Care Workshops and Citizen Forester Training. Lots of organizations and youth groups are eager to plant trees and citizen foresters head up these projects. For more information email firstname.lastname@example.org or call 602-465-3762.