Seeing the forest for the trees

Between January 2007 and now, the village has taken down 899 trees.  Let’s call it 900.  This doesn’t count trees taken down on private property (the village has no way to track that), trees on park district land, or school district land.  The village planted 1,127 trees in that same time frame.  More trees going in than being taken out.

So what’s the problem?

Each mature tree does a couple key things for Downers Grove:

Trees reduce stormwater. They act as giant sponges that absorb 660 gallons of water in the first 24 hours of a rain event.  Our 23,000 mature parkway trees absorb over 15 million gallons of initial rainfall.

Trees reduce energy bills. They provide 133 square feet of canopy coverage.  That seemed like a small area until I was told that represents solid coverage.  In real life, that canopy spreads over a much larger area, but it’s not a 100% solid canopy, and it doesn’t represent the crown volume, just the canopy top.  Underneath a tree it’s a couple degrees cooler in the summer, and a couple degrees warmer in the winter. Properly placed trees can reduce summer cooling costs by as much as 30%.

Trees increase air quality. They sequester 48 pounds of carbon dioxide each year, enough to offset the amount produced by driving a car 26,000 miles.  That same tree produces enough oxygen f in a season as 2 people inhale in a year.

Trees increase property values. Most studies say mature trees increase comparable home prices roughly 15%.  Some developers claim that clear cutting reduces construction costs, but they ignore cost reductions that can be realized by preserving existing mature trees.  What builder is against adding 15% to the value of a new home by not doing something?

The key word here is mature.  A tree takes 20+ years to mature, and none of these benefits kick in until it is a mature tree.  The 1,147 trees the village planted in the last two and a half years won’t “come on-line” until around 2027.

We’re going to lose our ash trees, too.  Two years ago the village made the decision to take out approximately 4,100 ash trees from our public parkways over the next 5-10 years, about 18% of our total parkway tree inventory doomed by the Emerald Ash Borer.

The net result on paper will be that the village, since it is planting trees faster than they are being removed, is okay.  The problem is, “trees-in/trees-out” is a false metric.  It doesn’t accurately assess and address that the “trees-in” don’t come on-line for twenty years, and the “trees-out” immediately reduce the village benefits.

For a council and staff facing budget problems, and looking at being forced to raise taxes, this is a huge problem, and here’s why.

By 2017, if the village makes good on plans to aggressively address EAB, we will have lost 5,000 mature trees from the public parkways.  Add in only the total of ash tree loss in Downers Grove, and we lose over 1,000,000 square feet of canopy coverage.  That’s one million square feet of solid coverage; about 20 football fields of total shade stripped bare, needing more cooling, more energy use. Of course, trees aren’t solid, so the area effected is, in reality, much larger.

Back to just the 5,000 parkway trees.  120 tons of CO2 not sequestered.  Oxygen for 10,000 people not produced.  Home value growth, real estate tax growth, stunted.  And that’s the minor impact to the village.

Those 5,000 trees?  Where does the water go?  each one sponges up 660 gallons in the first 24 hours of a rain event.  that’s 3,300,000 gallons of water, or about 10.25 foot/acres of water looking for basements and back yards.

I did some math on Washington Park.  Engineering, design, construction, interest and principal on the bonds, change orders (so far): it’s a $4.3 million dollar project that will hold 8.7 foot/acres of water.

$4.3 million to hold 8.7 foot/acres.  By 2017, 10.25 foot/acres of additional water in the village with no place to go.  And that’s not counting trees removed from park land, school land, and private property.  We’re not running fast enough to stay on the treadmill, but we are creating the necessity of another big expensive water retention project to help stay even.  Not to get ahead of the problem, just to tread water.

Flooding was a recurring issue in TCD3, and it’s been a recurring issue for many years.  The village committed to an initial borrowing of $25 million to address stormwater issues, with plenty more to come.  There’s talk of a stormwater tax to fund the improvements.  But if we immediately build the problem back in right along with the solutions, we don’t move forward; we just spend a lot of money for things to seem to stay the same.

We do know some things for certain.  No one wants to pay more taxes if they don’t have to.  Paying more for the same apparent services is frustrating.  Mature trees save money, now and in the future, whether they are on parkways, private property, parks, or by schools.  They create higher real estate property values, in turn creating higher tax revenues.  People have less issue with paying more if they get more, and trees get us more value for our homes.

In three weeks the final TCD3 report will be published.  It’s already been talked over that the key outcome is a need for better communications, and neighborhood groups have been discussed as a mechanism for that better communication.  That doesn’t seem to apply directly to this type of issue, but this issue is a critical lever in any new comprehensive village plan.  In the village stats, the tree problem is being addressed; more trees are being planted than are being removed.  In the real world, we still need a proper set of metrics so we can make accurate informed decisions about what we need to be doing.  By the metrics of water absorption, carbon sequestration, energy costs, and oxygen production, we’re failing.