Billy Beck | Extension Forestry Specialist, Iowa State University Extension and Outreach | Assistant Professor, Department of Natural Resource Ecology and Management
Did you know that nearly three million acres of forest stand tall within Iowa’s border? That around one hundred and fifty thousand Iowans own forestland and sell 10-35 million dollars of standing timber annually? In 2016, forestry and forest products produced 4.3 billion dollars in economic output and supported nearly 30,000 jobs in Iowa.
Iowa State University is home to one of the oldest forestry programs in the United States. As an Extension Forestry Specialist, I work daily to remind Iowans that trees, forests, and forestry hold great significance in Iowa’s past, present, and future. They are part of Iowa and help define who we are, just like corn, hogs, and prairie. Why is it that trees, forests, and forestry are generally absent from Iowa’s water quality conversation? From on-farm practices to our statewide vision (i.e., Iowa Nutrient Reduction Strategy), trees are rarely, if ever, mentioned as a part of our water quality improvement strategies.
We’ve done an impressive job in the Midwest to alter our landscape (e.g., landcover conversion, stream channelization) for the purpose of getting water out of fields, into streams, and out of watersheds as fast as possible. The result is what hydrologists refer to as “flashy flow”, where streams exhibit rapid rises in stage immediately following storm events. This altered (flashy) hydrology subjects our streams to increased erosive power, which contributes greatly to Iowa’s current water quality and quantity (i.e., flooding) issues.
Trees and forests help address flashiness, mitigate the effects, and work to restore a more natural hydrology which will lead to better water quality and more stable quantity. Upland forest canopies intercept a portion of rainfall and prevent it from rushing into streams. Roots increase the infiltration capacity of the soil, reducing overland flow and associated erosion. Transpiration pulls moisture from soil, further increasing its ability to absorb rainfall, reduce overland flow, and deliver water to streams slowly through shallow groundwater. Floodplain forests provide resistance against out-of-bank flows, reducing floodplain scour and lessening downstream flood damage. By slowing flood velocities, their upright stems also encourage deposition of sediment and phosphorus on floodplains (a potentially huge nutrient sink). Trees along streams armor streambanks against erosive flows, and roots increase the tensile strength of streambank soils. The shade they create regulates stream temperature, mitigating massive diurnal dissolved oxygen swings.
Many landowners praise streambank trees for keeping flood debris from entering their fields. Trees that fall in streams and other in-channel large woody material may be unsightly to many folks, however, even these provide significant benefit through increase in flow resistance, trapping and storage of sediment and phosphorus, and creation of prime habitat for aquatic biota. In-channel wood also redirects flow towards streambanks, working to reestablish the natural meander pattern of streams, thus lessening slopes and further “slowing the flow”.
So, why would such a powerful tool be overlooked so often? Why are efforts to establish, manage, and protect streamside (riparian) forests minimized in the Midwest? I believe part of the answer comes down to landowner unfamiliarity with trees. This is no knock against Midwestern landowners (they are the best people on the planet in my book), it’s just that trees are challenging, especially if you lack experience. Trees are different from grass – you can’t simply plant trees in the ground, walk away, and expect success. Trees take advanced planning and site preparation, and at least three years of dedicated maintenance (e.g., weed control) to establish. When these don’t occur, plantings fail, neighbors notice, and word gets around the county that “trees don’t work”.
Management of existing forests is no less challenging. It takes a “100-year mentality,” and willingness to part with annual returns. In addition, landowners struggle to understand the true value of their timber. This spells danger when someone knocks on their door and offers them “ten thousand bucks” for the walnuts on the back 40. What seems like an instant windfall is often a severe undercut. Before you take that offer, reach out to the many forestry resources, technical assistance, and expertise available to Iowa landowners. Unfortunately, many are unaware these resources exist.
The first, and most critical step to a successful forestry project is to connect with a professional forester. Be they a public (e.g., Iowa DNR), or a private consulting forester, these experts are your guide to a successful forestry project. From planning and planting, to forest stand improvement (thinning) and timber harvest, a forester will guarantee you maximize the benefits (both ecological and financial) of your forest resource. For further details on maximizing your forest resources, join my April 22 Iowa Learning Farms webinar.
On February 27, I brought together nineteen forestry and water quality experts from across Iowa to explore the question as to why trees are often disregarded as a water quality enhancement tool. The participants in this Forestry and Water Quality Summit agreed that trees and forests are a tough sell to policy makers because they are not a “practice” or an engineered structure you can simply install and expect instant results. Trees take time. There is a multi-year lag between implementation of trees and water quality enhancement. For the foresters in the room, this was to be expected. Everyone agreed that everyone needed more of that “100-year mentality” and to plant more trees.
More importantly, we all agreed that we need Iowa-specific data that quantify tree and forest water quality benefits (e.g., flood peak reduction and nutrient reduction). While such data exist nationally and globally, it is difficult to apply that information to Iowa’s unique stream corridors and watersheds that are often highly-altered and highly-unstable.
Are trees the “silver bullet” for Iowa water quality? No. Do they need to be recognized as a critical component in our water quality efforts? Absolutely. To succeed in reducing nutrient levels in our water bodies, we will need a suite of practices. Like wetlands and prairie strips, trees offer additional environmental benefits. I am so thrilled be a part of the Conservation Learning Group and to partner with the Iowa Learning Farms and forestry professionals state-wide to firmly establish trees in Iowa’s water quality conversation!
For information on forestry resources available to Iowa landowners, visit the Forestry section of the Iowa State University Extension and Outreach Natural Resource Stewardship website.
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