The Benefits of Streamside Trees by Crystal Gilchrist at Perkiomen Watershed

Column from Crystal Gilchrist, AICP. Executive Director at Perkiomen Watershed.

For thousands of years, thick forests lined every stream and riverbank in the Schuylkill River watershed. The huge trees and dense underbrush were an awesome sight to early European explorers whose homeland had long been deforested. As William Penn looked at the trees that lined the banks of the Schuylkill, the fish that filled its waters and the wild game that flourished in the vast forests, he certainly understood their value as timber and food. But he little appreciated the invisible but more important value of “Penn’s Woods” as the provider of critical “ecosystem services.”

Much of the extensive forests that cloaked the Schuylkill River and the surrounding countryside in colonial times are long gone and current landscapes can be nearly devoid of even street trees in some communities. The trees along the streams and rivers disappeared as industrial developments took their place. As the trees were removed, water quality in creeks, streams, the river and the habitats that surrounded them suffered greatly. It was not until the passage of the Clean Water Act that industrial pollutants began to be cleaned up. The fish consumption advisories, concerns about swimming in local waters and increasing costs of providing clean drinking water that were once commonplace are occurring less and less. 

However, industrial, “point source” pollutants are being replaced by a myriad of “non-point” source pollutants. Today our creeks and the surrounding habitats are being damaged by streambank erosion caused by poorly managed stormwater run-off, petroleum by-products that wash from parking lots, lawn chemicals and animal wastes from our pets and large agricultural operations. In short, today’s polluters are all of us!

Fortunately, more and more people are becoming aware of how we all contribute to poor water quality and are taking actions to make a difference. Many communities are relearning the story of trees and the ecosystem services they provide. Forest ecosystem services include cleaning carbon dioxide from the air and replacing it with oxygen, absorbing stormwater and reducing the potential for flash flooding, shading us from the sun’s heat & UV rays in the summer while evergreens can help reduce heat loss in the winter. Each tree is also a mini “carbon bank”, storing carbon that would otherwise contribute to global warming.

The trees that are streamside form a riparian buffer. Riparian buffers are critical to stream health, not only adjacent to the forested area but also to all locations downstream. The trees and undergrowth of riparian buffers serve as a natural filter that keeps pollutants out of streams and reduces the proliferation and downstream transport of water borne pathogens. Trees and other native plants also help stabilize stream banks to prevent erosion, they provide food and habitat for fish and other aquatic life; they protect streams from high temperatures and UV light and reduce the oxygen depletion that results from excessive algae growth.

Riparian buffers provide community benefits as well. They act as natural flood regulators by slowing and absorbing storm water; they provide natural habitat for birds and other wildlife that would otherwise be looking for a home in neighborhoods; they create natural visual breaks and absorb noise.

The Perkiomen Creek watershed is fortunate to still be largely forested. Many of the smaller creeks and headwaters areas retain their natural vegetation. In fact, the Upper Perkiomen Creek, including all reaches upstream of the Green Lane Reservoir are awaiting the final determination from the PA DEP to upgrade the creek classifications to Exceptional Value, the highest designation for waterways in Pennsylvania. To a large extent, this exceptional water quality is provided, and protected, by the native trees, shrubs and herbaceous plants of our forests and riparian buffers.

Whether you have a creek on your property or not, planting trees can be an easy way to improve your local and global environments. Each new native tree helps bring us back to enjoying the ecosystem services once taken for granted in the early days of Penn’s Woods. So if you are concerned with local water quality or stormwater issues, the advice from the Perkiomen Watershed Conservancy will be the same – plant more trees and go native!

(Excerpts from materials provided by the Stroud Water Research Center, http://www.stroudcenter.org and the Montgomery County Natural Areas Inventory)

Post a comment

Log In or Register to comment on this entry.