Jake Hendee, Consulting Forester
Each day, Corps of Engineers foresters
commute to the worksite by boat.
As part of a recent Illinois and Iowa Society of American Foresters field tour, I had the opportunity to see some unique forestry performed by the U.S. Army Corps of Engineers along the Mississippi River. With 50,000 acres to manage, they are able to demonstrate and test a number of practices that can be used to better manage the frequently flooded riparian areas of private woodlots as well.
After a short commute by boat, we found ourselves island hopping through the refuge from forest management project to forest management project.
The corps has a heavy emphasis upon wildlife habitat. As such, they focus upon maintaining plentiful hard mast provided by oaks in the Mississippi bottoms. Unfortunately, back-to-back-to-back 500-year floods have taken their toll upon the species composition of the forest, favoring only the most flood tolerant trees including silver maples and cottonwoods.
Underplanted bur oak reaching for sunlight amongst cottonwoods
In several projects, the foresters have thinned the overstory and midstory to provide sufficient light for oak survival, and then underplanted oaks. They've tried direct seeding, bare root seedlings, and containerized Forrest Keeling Nursery RPM planting stock. The latter have been, by far, the most successful trees.
In this cottonwood forest, the species composition is slowly changing from complete
canopy cover of cottonwood to include a few hard mast producing oaks in the midstory
On private lands, oak underplanting can be a necessary but expensive step to undertake in uplands and bottomlands. Fortunately, the NRCS Environmental Quality Incentives Program has recognized this need, and provides the appropriate cost share funding to undertake such a project, whether you use the more budget friendly bareroot seedlings or the very effective containerized planting stock.
Bottomland Forest Restoration
After acquiring thousands of acres to compensate for the impacts of water level changes caused by the lock and dam system, the Corps has been converting frequently flooded agricultural land to bottomland forests. While they have had limited success getting bare root seedlings and seeds established due to heavy browse and difficulty of controlling competing weeds at remote locations, they have had great success in this swamp white oak plantation planted in the mid 1990s.
In this planting, they also used Forrest Keeling Root Production Method planting stock. While it is certainly possible to produce a successful plantation without expensive planting stock, the lack of maintenance required by RPM stock and the high survival rate may mean it's not that much more expensive to go with the containerized trees.
Other Tree Planting Approaches
Where traditional tree planting methods have proven difficult because of competing vegetation, just creating a little bit of shade from canopy closure can go a long way toward establishing a restoration planting. In this one forest restoration planting, they've resorted to willow and cottonwood cuttings to create some canopy closure. Eventually, that canopy closure may suppress weeds and allow smaller seedlings to poke through the gaps in the canopy. In the pictures below, the sticks that look like fence posts (left photo) are actually massive cuttings having no difficulty taking root and leafing out (right photo). These new trees will produce seeds within the next couple years.
Invasive Species in the Mississippi River Bottoms
Invasive species are becoming more and more of a problem everywhere. Invasions of kudzu-like Japanese hops and heavy mats of reed canary grass mean that anytime forest management creates a gap in the forest canopy, invasives may sprout more vigorously than the preferred tree seedlings. In a relatively short lived forest such as the silver maple dominated forests of the bottoms, what will fill the gaps when the forest declines? Invasive plants are increasingly up to the task if they are not controlled.
A reed canary grass thicket may replace this wind-damaged silver maple stand
Reed canary grass, garlic mustard (pictured left below), and Japanese hops (pictured right below) are invasive plants that call the Mississippi bottoms home. On private lands, it is imperative to monitor and treat outbreaks of invasive species in order to promote tree regeneration and native understory plant diversity.
Patch Cuts to Restore Forests
In some situations, forests may be so degraded by mismanagement that patch cuts or clearcuts are an option. Fortunately, forest ecosystems are resilient systems that quickly recover. Here, members of the Illinois and Iowa chapters of the Society of American Foresters stand in the middle of a recovered 1983 patch cut.
On private lands, forest aesthetics is almost always a top goal of landowners. A patch cut would be recommended in only the most dire of situations. Usually we can accomplish forest restoration with more minimal visual impacts.
A Day's Wrap Up
Forestry is not a controlled science. It's an art that requires navigating hundreds of changing variables and site-specific situations. However, we are constantly innovating to make sure that we keep up with new management techniques, newest threats, and newest science. How can these bottomland management techniques benefit your woodland?
A big thanks to the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the Illinois Department of Natural Resources, and the Illinois and Iowa Chapters of the Society of American Foresters for making this tour possible!
A few more pictures from the tour...
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