The Value of a Tree: A Brief look into I-Tree and Consideration of How Trees Benefit Our Lives
By: Jordan Wilkinson, Designer at DG2 Design Landscape Architecture
As landscape architects and designers, trees are one of the many ‘colors in our palette’ available to help us shape spaces and create valuable environments. It’s helpful to take a step back occasionally and try to remind ourselves that trees have dozens of different benefits to environments (both built and natural) and should be viewed as an investment. Exactly how valuable is a tree? How can we even begin to put a dollar amount to a living, breathing organism as common as a tree and determine a return on investment? There are many professionals and tools who have done just that. By considering the economic and ecological benefits we can start to understand how much trees improve our planet, but quantifying the cultural and societal benefits of a tree can be quite challenging and may differ from person to person.
Sometime within the past year – we discovered i-Tree, a relatively new software program from the USDA Forest Service (which is completely free to download), and has several different options that can be used to calculate some of the more quantifiable benefits of trees and canopy cover. The tools available through i-Tree address beneficial factors ranging from stormwater quality and air pollution reduction to shade benefits and energy reduction. These numbers can ultimately be used to justify design decisions or save existing trees on a job site. Results can also be used to make a case for increased property values over time.
All of these ecological and economic benefits can be very compelling, but there is still so much more that makes a tree valuable on the human level. Many of these benefits are hard to quantify, and be subjective. For example, I love the Red Maple my parents planted in the front yard of my childhood home over 20 years ago. This tree has specific meaning to me even though I rarely see it and haven’t lived there for years. I was able to see it grow and have fond memories of playing near it that cannot be quantified into a price tag. Memories are nice, but research has shown that trees really do improve our physical health in a number of different ways. In this Governing.com article (http://www.governing.com/topics/transportation-infrastructure/gov-itree-calculates-trees-economic-worth.html) from August 2013, Elizabeth Daigneau summarizes a direct link between tree loss and human death from respiratory disease that brings a whole other level of tree value to human lives:
“Conducted over 18 years, research from the U.S. Forest Service has found a correlation between tree loss and human mortality. According to their findings, the loss of trees was associated with about seven additional deaths per year from respiratory causes and almost 17 additional deaths per year from cardiovascular causes per 100,000 adults. That, say researchers, comes out to more than 21,000 deaths in total. It seems trees have a value that goes far beyond dollars and cents.”