The Benefits of Street Trees

Kamloops
Originally uploaded by Spatial Mongrel

The new Live Smart BC Speech from the Throne raised some interesting points which YUPPIES will be commenting on over the next few weeks. One item in particular caught our attention, and that was mention of a new urban afforestation program called Trees for Tomorrow which will provide funding and incentives to dramatically increase the number of trees in our urban environment. To that end, we thought it would be good to provide a few resources to help gauge the cost and value of what trees are worth in the environment, and to focus in on street trees since our public ROWs are where we can start planting immediately - and save what we already have.

Tree Valuation
A quick review of literature relating to tree valuation (Council of Tree and Landscape Appraisers (1992) and International Society of Arboriculture (ISA) publications (ACRT 1997)), produces the following rough "rule-of-thumb" equation for quickly estimating the compensatory replacement value for a tree:

Basic Value = CS * $/cm2

Where

• CS = cross-sectional area of the tree at about 1.4 m up
• $/cm2 = the dollar value of the tree to be replaced, based on species and region.

From looking around at the various landscaping companies and the trees they have on offer, the average price for a tree in the Interior BC market is around $7/cm2. This then provides the base replacement cost for a tree of similar size and character.

However, speaking with an arborist, the value then needs to be multiplied by 2.5 for installation and landscaping costs associated with planting - the bigger the tree, the more expensive.

For example, a tree with a radius of 15 cm (equivalent to a good-sized, 25-year old maple) would be calculated the following way:

Area = 3.14 * (15)^2
Area = 706.5 cm2
Basic Value = 706.5 cm2 * $7/cm2
Basic Value = $4,900
Installation Value = $4,900 *2.5
Full Value = $12,300

This valuation does not include other benefits associated with street trees or long-term cost-benefits, just straight out replacement cost. So as you can see, trees have a lot of built-in value!

Other benefits are nicely summarized by the following presentation from Dan Burden at Walkable Communities. These include benefits such as:

• pollution control (absorption of greenhouse gas emissions, production of oxygen and co2 retention)
• aesthetic enhancement - trees have a proven market impact of between 15% - 25% to the value of real-estate with a mature canopy spread (not insignificant!)

An "urban forest" program is a welcome program to introduce in any town, and makes a lot of sense for the health of a community. There are many resources out there to help jump into such a program, and we urge you to post any information you find in the comments below.