As summer approaches, many of you may be clearing your properties to create space along your shoreline for summer’s recreational activities. Though it might be tempting, the Lake Leelanau Lake Association (LLLA) encourages you not to remove any trees, branches, or logs from your shoreline. This “woody debris” is an integral part of keeping Lake Leelanau and that which lives in it healthy and thriving. Read on to learn more about the importance of woody debris on lakeshores!
Why is Woody Debris on Lakeshores Good?
Woody debris is a blanket term for any partially or fully submerged trees and branches in the nearshore areas of a lake. You might also hear it called fish sticks, turtle logs, coarse woody structures, bundled wood debris, drop trees, or shoreline woody habitat.
Woody debris has many advantages that help enhance the lake’s water quality. Woody debris:
- Controls erosion by stabilizing the shoreline,
- Improves water clarity by preventing the suspension of sediment,
- Attracts more fish by providing habitat for juveniles,
- Provides cover, feeding, nesting, and basking habitat for birds, turtles, and other wildlife.
As the rhyme goes: Wood is Good!
Restoring the Shoreline
Woody debris is missing near our shorelines—a result of the removal of woody debris on lakeshores conducted over time and primarily by lakefront property owners. Many people do so to:
- Update for aesthetic reasons,
- Enlarge and widen water views,
- Create swimming and play areas near docks and shores,
- Maintain clearance for boating activities or navigation, and
- Deter lost hooks, lines, and related floating fishing gear.
Many field studies at northern inland lakes (Christensen, 1996; Sass, 2006) have documented that parcel-by-parcel shoreline development has significantly removed live trees and vegetation. Typically, removal extends to near-shore submerged trees, limbs, branches, roots, and wood fragments. Aerial drone data collected in LLLA's shoreline survey confirm this situation for much of Lake Leelanau.
Negative impacts arise with wood removal, such as:
- shoreline erosion,
- suspension of sediments,
- loss of shade,
- loss of fish colonization (shelter, feeding, nesting, and spawning habitat),
- loss of substrates for insects and algae, and
- loss of usage by turtles, birds, and other wildlife.
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) cite that forty percent of Michigan’s inland lakes have poor lakeshore habitat, leading to poor biological health.
What Can We Do With Woody Debris?
If woody debris has recently fallen onto your shoreline, the best thing to do is leave it be! Often there is plenty of room to re-wood within, say, a 100-foot shoreline to accomplish homeowner recreational wants and lake health objectives.
If you do not have any existing debris, however, intentional restoration of aquatic habitats on our shorelines is recognized by EGLE as a best management practice. Re-wooding the waters means installing, placing, and securing partially or fully submerged trees and branches in nearshore areas where little to none exist today.
Trees and branches that naturally fall into the lake can be retained as part of an “aquatic garden” of native plants and features within your riparian area. However, the planned installation of shoreline or near shore woody structures requires a permit from EGLE, typically under Minor Permit or General Permit categories.
Planning Your Woody Structure Project
Such woody structures will vary, project to project. Tree diameters of 6 to 10 inches are common—singly or grouped. Recently live trees are preferred, 20 to 40 feet long. The tree shape and branches can be left “as is” or trimmed to improve placement objectives. Please consider the water depth (approximately 2 to 5 feet for the diversity of fish species) for much of the structure’s length.
EGLE requires the woody structures to be secured. Project site characteristics for wind and wave energy, as well as ice heave occurrences, may call for a more robust design to keep the structure in the long term. Published design suggestions (Fish Sticks, 2014) indicate that 3/8-inch galvanized steel works well when looped around the butt end of the tree and secured with cable clamps. The shoreline end goes around a live tree trunk (protected with a garden hose to prevent girdling) or a sturdy anchor on shore. Some projects secure the cable to deep-set steel or wooden fence posts. Where the lateral movement of grouped fish sticks is a concern, ¼ inch in the cable is connected at selected intersections of the logs.
While homeowners can accomplish these projects, landscape/shoreline restoration firms have the experience and heavy machinery necessary. Len Allgaier, CEO of Peninsula Pavers, Inc., notes:
“If steel cable is not practical to secure the fish sticks and turtle logs, I like to trench about one-third of the trunk length (landward) in the soil, using wood stakes within the trimmed branches, particularly where a shoreline vegetative buffer project is envisioned.”
Installing natural features such as turtle logs and related woody structures is desirable and healthy for shorelines. If you have a question about woody debris on lakeshores and how to re-wood the waters on Lake Leelanau, please contact LLLA’s Lake Steward Ambassador, Nancy Popa, at 231-944-9509 or [email protected].