[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/02/EW-03-16-12-Tree-Planting.mp3|titles=EW 03-16-12 Tree Planting]
Renewable energy is a small part of our nation’s energy portfolio. In 2011, only 14% of our electricity came from renewable sources. As we wean off fossil fuels, trees can be an important ally in offsetting associated carbon emissions.
When plants grow, they take up carbon dioxide from the air. Young trees grow quickly, and large-scale plantings result in a significant removal of carbon dioxide from Earth’s atmosphere.
Since we know young trees accumulate carbon faster than mature trees, why not cull old trees in favor of young forests?
Reality is not that simple: when an old tree is cut, if it is burned or allowed to decay, nearly all the carbon stored in its wood is returned to the atmosphere within a few years. This outpaces carbon uptake by young trees planted to replace it. Unless mature wood is used in long-lived products—like housing—replacing old trees with young trees has little benefit to the climate.
But new plantings on barren lands can have a positive impact, especially when native species are selected over ornamentals. Native trees provide important wildlife habitat, and compared to ornamentals, they tend to grow to larger sizes and require less maintenance.
Carbon uptake is best when native trees are allowed to re-colonize areas that were once lost to excess lawns, sprawl, abandoned strip malls, and other non-productive uses. High-density suburban forest can provide an oasis for migrating birds and hikers while also helping mitigate carbon emissions.
Photo, taken on April 26, 2008 using a Canon EOS 20D, courtesy of Alex Indigo via Flickr.