Eagle River Watershed Council: Healthy forests make for healthy watersheds
Walking through a forest is by far one of my favorites things to do. Honestly, just standing or being in a forest is enough for me. Looking up to a blue or starry sky through trees is comforting — slowing you down and creating a smaller world where reflection and stillness are possible. Forests provide me with a space to bask in the shade and hide from our more than 250 days of sun like a fern on the forest floor.
There is a whole lot of data to back up my views of a forest as it relates to forest bathing (the mental health practice of just being in nature), but there’s a whole lot more a forest provides for the health of a watershed.
The general definition of a forest is a large area of land dominated by trees, but depending on the geographic region, they can look very different. Our home in the High Rockies region has forests that are predominantly made up of aspens and a variety of evergreens. In the Southeast, however, forests contain evergreens and a mix of hardwoods like oak and hickory along with dense undergrowth. As they relate to water, forest processes throughout the world play important roles in ensuring high water quality, lower water temperatures and regulation of stream flows.
The saying goes that when it rains it pours, and though we don’t often see the rain here beyond afternoon downpours during our late summer monsoon season, trees play an important role when it does rain (and pour). Their leaves and branches slow the water down and regulate the amount of flow rushing over the ground, preventing floods and a rapid increase of water flowing through streams. Trees, specifically their roots, provide structure and stabilize banks. The combination of slowing the rain and adding a structure helps to keeps soil on the banks and sediment out of the rivers. High turbidity, or high levels of sediment, can negatively affect native fish and other aquatic life.
It’s worth noting that trees don’t necessarily keep rainwater from reaching streams. Rather, they play a key role in the water cycle, releasing moisture and oxygen into the atmosphere though transpiration and in turn influencing precipitation. Sure, they require water to grow, but trees and the forests they thrive in are a system that slowly releases water back into the ground during rain events. The rate of infiltration, or water moving through the soil, increases in forests. A study completed in 1980 showed that a forest had an infiltration rate of 12.4 inches per hour, while turf grass had a rate of only 4.4 inches per hour.
Quality of water is just as important as quantity, and forests are imperative in ensuring high-quality water within a watershed. The impact of forests on river health has been quantified as well in the context of reduced drinking water treatment cost.
Conserved forests and natural landscapes can help reduce the need for water filtration. New York City invested $1.5 billion in forest conservation within its treatment watershed, which saved the city from building a new, $6-8 billion water treatment plant in the 1990s. A study conducted in 2006 by the Trust for Public Land surveyed 60 water treatment facilities and found a significant and direct relationship between the percentage of forest cover in a collection area, source water quality, and drinking water treatment costs.
Remember my need for shade and reprieve from the hot, smoldering sun of Colorado? It is also critical for many aquatic species. Brook trout, for example, are quite sensitive to changes in water temperatures and require cool waters to lay their eggs. The forest canopy helps to keep river and creek temperatures in check throughout the hot summer months.
Natural infrastructure, like a forest, is critical and complementary alongside our man-made systems. Gifford Pinchot, a renowned conservationist and founder of the United States Forest Service, said “the relationship between forests and rivers is like father and son. No father, no son.” ‘This week is National Forest Week, a time to share our National Forest stories and celebrate their importance. As you are out enjoying the National Forests surrounding our home, take some time to appreciate all they do for us and for our rivers. Join the Watershed Council to learn more about our forests as we share fun facts, activity ideas and resources on social media.
James Dilzell is the education and outreach coordinator for Eagle River Watershed Council. The Watershed Council has a mission to advocate for the health and conservation of the Upper Colorado and Eagle River basins through research, education, and projects. Contact the Watershed Council at (970) 827-5406 or visit erwc.org.