Davey Tree Expert Company has a calculator on their website where individuals can calculate the annual dollar value of all the benefits the trees on their property provide -- to them and to the community at large!For example, the 39 inch bur oak provides nearly $400 worth of benefits annually, including more than $195 in stormwater management by eliminating over 7,000 gallons of stormwater runoff every year! Without that tree, all of that rain water would flow rapidly to the street, helping to overwhelm the stormsewers.
Now, when I add up the stormwater caught by all of my trees: three bur oaks, one white oak, a cottonwood, two maples, two pears, and two honey locusts, the stormwater savings alone of these trees amounts to nearly $2000 a year, or 65,000 gallons of stormwater that is intercepted rather than running off into the stormsewers!
According to the Center for Urban Forest Research, trees act as mini-reservoirs, controlling runoff at the source. Trees reduce runoff by:
- Intercepting and holding rain on leaves, branches and bark
- Increasing infiltration and storage of rainwater through the tree's root system
- Reducing soil erosion by slowing rainfall before it strikes the soil
And you know what, the trees cost us virtually nothing. Sure, we rake the leaves in the fall (which is good exercise, by the way), and pick up branches after a windstorm, but the annual cost is minimal.
This kind of information makes me think that more communities could invest in promoting city trees as part of their stormwater management program rather than (or in addition to) expanding their stormsewer systems. I would guess that it is much less expensive to manage 7,000 gallons of water with a mature tree than by building more stormsewers.
According to American Forests: As communities grow, trees are removed to make way for impervious surfaces such as parking lots, roads and buildings. Our studies show that impervious surfaces have increased by 20% over the past 2 decades in urban areas. Constructed stormwater facilities are created to compensate for the tree loss. These facilities are expensive to build and maintain. The cost has been calculated to be in excess of $100 billion nationally.
2 comments:
Back in the mid-1980's I was in charge of a major newspaper production plant project in south Florida. The site was bare, except for some palm trees and live oaks. The authorities required us to inventory all trees above a certain size in cooperation with the city forester. He then directed us as to which trees could be removed (or relocated) in light of the plans to build a 7 acre plant on the site, along with parking and trucking area pavements. We were also obligated to provide landscaped islands throughout the parking areas on a proportional basis.
In addition, because south Florida is subject to infiltration of salt water into the water table, we were obligated to provide a stormwater retention pond to control runoff and maximize the infiltration of storm water into the water table. Notice I said retention (which holds water) and not detention (which merely slows the outflow of water).
It is interesting to me that they were 25 years ahead of us here in McHenry County — if indeed we're even now considering such provisions as part of our new 2030 plan.
Our elementary days taught us that tree roots absorb water to live. A simple yet helpful way for us to be flood-free. These can't be taken out of consideration because they give us a better environment, too. Trees are also pleasing to the eye. It only takes good landscaping for these to be effective. :)
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