Tuesday, October 9, 2012

Justin Evertson

Fall colors have arrived (and will fade quickly)! We've had a couple of hard frosts recently so the growing season is pretty much over. After a tough year of extreme heat and drought, a friend aptly described the frost as a "mercy killing". I concur.

Green ash and white ash along a street in Waverly.
As we leave behind one of the driest summers on record, many of us are left wondering what the future might hold for the trees of Lincoln and other Nebraska communities. This year’s drought has killed many trees across the state and it is almost certain that many more have been weekend and will likely die in the coming years as additional stresses take their toll. With increasing weather extremes (including the likelihood of more heat and drought) and with advancing diseases and insect pests such as emerald ash borer adding even more threats, it might be fair to ask: “Why should we work hard for trees with so many looming problems?” For me the answer is simple: because trees are still vitally important to our daily lives! The list of benefits that trees provide is extensive and would take a whole document to summarize. But there are three primary ones that we would NOT want to live without, or even have them marginally reduced: shade, stormwater absorption and beauty.

First, the shade that trees provide helps counter the urban heat island effect and can reduce a city’s temperature 5 to 10 degrees on a hot summer day. Not only is the community kept more comfortable, our energy costs are greatly reduced. Anyone paying for air conditioning is saving 10-20 percent or more on their electricity bill! The collective savings to all of us is in the millions of dollars. In terms of carbon storage and its impact on climate, trees are doubly beneficial as they directly store carbon in their wood and help reduce the release of carbon into the atmosphere by greatly reducing energy consumption.

 A second key benefit from trees relates to stormwater. Trees can capture and hold significant amounts of rain in their leafy canopies while their roots help soils more readily absorb moisture. It is estimated that collectively the community trees of Lincoln reduce peak stormwater flows by millions of gallons during rain events.  If our trees were suddenly gone, the amount of runoff from storms would likely overwhelm our drainage systems, greatly increasing flood damage, stream erosion and the pollution of waterways. The costs of improving our storm drainage systems to handle this extra water would be incredibly expensive.

Finally, trees are critical to our quality of life for the beauty and environmental benefits they provide. Over the years I’ve heard from many Lincoln visitors how impressed they are by all our large trees. We should not underestimate the value of this leafy canopy in attracting visitors, new residents and new businesses to town. And in the fall, when the air becomes crisp and our attention turns to the ritual of football, just think how much better it is thanks to the bright colors of the changing leaves. In addition to their beauty, trees provide cover and food for a wide variety of important birds and other wildlife. Without our trees we wouldn’t have cardinals, juncos, orioles, chickadees, waxwings and so many other colorful birds. And perhaps most importantly for me, without trees, I wouldn’t be able to enjoy pecan pie. How horrible!

In my next post I'll offer some thoughts about how we might better enable our community forests to survive a hotter future that will surely include more watering restrictions.

1 comment:

  1. Beautiful scenery! The color of the leaves bring about a calm state of mind and emotion. Anyway, it is true that trees improve stream quality primarily by decreasing the amount of stormwater runoff that reaches local waters. Their presence also helps slow down and temporarily store runoff. So, we have to take into serious consideration the preservations of trees because we are the primary beneficiaries of their purpose.

    Monica Barnes