Floodplain Forest Enhancement - Mississippi River
Floodplain forest enhancement projects were implemented at 10 sites covering 292 acres along the Mississippi River from Red Wing to the Iowa border. We completed site preparation; controlled invasive species; planted trees and shrubs using a combination of direct seeding, bare root seedlings and large, potted trees; protected trees from deer and voles; completed post tree planting weed control; and installed willow and cottonwood cuttings. Outcomes varied by site, ranging from poor to excellent tree seedling survival.
Audubon’s floodplain forest enhancement program was designed to sustain floodplain forest along the Mississippi River and the lower ends of major tributaries. These forests, which provide critical habitat for forest dependent birds, are under threat from invasive species like reed canary grass. Without active management these forests will continue to decline over time.
Our program focused on controlling invasive species and regenerating a variety of tree and shrub species. We prepared sites for planting or natural regeneration using herbicide, disking, or mowing; planted tree seedlings, cottonwood cuttings, or direct seeded; protected trees from deer and voles; improved tree vigor and growth through selective thinning; and controlled weeds (herbicide, mowing) after planting.
Our geographic scope included the Mississippi River from Hastings to the Iowa border, and the lower ends of major tributaries. Much of this area included state forest, Wildlife Management Areas, or National Wildlife and Fish Refuge lands.
Our priorities were determined in cooperation with MN DNR, US Fish and Wildlife Service, and US Army Corps of Engineers. All projects were on public lands owned and managed by these agencies. Priorities were based on forest condition and threats, habitat needs, logistics, and access. Our goal was to prevent or control invasive species long enough to establish forest canopy and maintain a diverse forest structure that benefits birds and other wildlife. Our objectives were designed to utilize a variety of enhancement tools, monitor results, and apply that information to designing new projects.
A description of each project is provided below. For several sites additional work will be completed with Phase 2 of our floodplain forest enhancement program.
At Gores WMA, a 20-acre site north of Red Wing, we completed site preparation, planted bare root seedlings on 10 acres, and completed post planting weed control following tree planting on 10 additional acres that had been previously planted by US Army Corps of Engineers.
At the Cannon River Collischan Road Willow Project, a 10-acre site near Red Wing, we treated reed canary grass and cut willow trees along strips to encourage aggressive expansion of willows to prevent reed canary grass encroachment into adjacent high quality floodplain forest.
At Dukes Pond, a 22-acre site near Red Wing, we completed site preparation on 15 acres along the edge of existing high quality floodplain forest. Our intention was to plant trees the next fall on the treated area, but unusually high water prevented this from occurring. Bare root seedlings and potted trees had been purchased, so instead of planting the treated areas we planted 7 adjacent acres where DNR Forestry was planning a timber harvest. The planted trees will regenerate when the canopy opens up following harvest, and before reed canary grass can become established.
At North Clear Lake, a 9-acre site north of Red Wing, bare root seedlings were planted in the understory of existing floodplain forest scheduled for harvest by DNR Forestry. The planted trees will give a head start to regeneration when the canopy opens up following harvest, and before reed canary grass can become established.
At East Indian Creek Delta, a 55-acre site north of Weaver, site preparation was completed and tree and shrub seedlings were planted in an area dominated by ash trees. Shade tolerant seedlings will grow when the canopy opens up due to the death and decline of older trees.
At Whitewater Delta, a 51-acre site near Weaver, buckthorn was removed and bare root seedlings and potted trees were planted in an area dominated by ash trees with pockets of reed canary grass. The seedlings will grow when the canopy opens up due to emerald ash borer impacts on the exiting trees.
At Whalen Tract, a 55-acre site just north of the Iowa border, a variety of activities were completed including site preparation, tree planting, cottonwood cuttings, and post planting weed control.
At Whitewater DNR, a 16-acre site approximately 5 miles upstream of the mouth of the Whitewater River, site preparation and direct seeding were completed.
At Cannon River Bottoms State Forest, a 30-acre site near Red Wing, site preparation was completed and tree seedlings and potted trees were planted in open pockets of reed canary grass within existing forest scheduled for harvest.
At Root River, a 93-acre site near La Crescent, a variety of activities were completed including site preparation, tree planting, cottonwood cuttings, direct seeding, and post planting weed control.
At four of the above sites (Cannon River Collischan Road Willow project, Whitewater DNR, Root River, Whalen Tract) up to 8 acres within or near each site was also treated for reed canary grass and planted with different tree species and stock types. This was part of a LCCMR study evaluating reed canary grass control, and tree survival and growth.
Evaluating success will take time. Because trees are slow growing, it can take a decade or longer for them to grow large enough to form a canopy, which will ultimately determine the success of these projects. Preliminary findings indicate initial survival of seedlings was variable. At some sites, post planting observations suggest low survival, however, small seedlings are difficult to locate in the forest understory. First year survival of bare root seedlings at the LCCMR study sites was 80-90%. Survival of potted trees at many sites was good, however there was some damage from deer.
Other findings resulting from this grant included: post tree planting weed control and maintenance is essential for tree seedling survival; tree guards and deer repellent are effective at protecting trees from deer and voles; cottonwood cuttings were relatively easy to install and effective at establishing trees; swamp white oak were resilient, relatively fast growing, and resistant to deer browse making them a good choice for these sites; plantings on drier sites, with proper maintenance, take less time to establish than wetter sites; good natural regeneration can occur on some sites after exposing mineral soils; and back-up sites are needed to adjust to flooding situations which may prevent scheduled tree plantings. These findings have been incorporated into project management prescriptions.
$300,000 is to the commissioner of natural resources for an agreement with National Audubon Society to enhance floodplain forest habitat for wildlife on public lands along the Mississippi River. A list of restorations and enhancements must be provided as part of the required accomplishment plan.
Healthier populations of endangered, threatened, and special concern species as well as more common species. Large corridors and complexes of biologically diverse wildlife habitat typical of the unglaciated region are restored and protected.