Floodplain Forest Enhancement - Mississippi River, Phase 2
Reed canary grass is preventing natural regeneration of trees and threatening floodplain forests and wildlife along the Mississippi. This effort builds on previous LSOHC funding to control reed canary grass and plant trees as part of a long-term effort.
Audubon’s floodplain forest enhancement program was designed to help sustain and enhance floodplain forest
along the Mississippi River and the lower ends of major tributaries. The existing forest is dominated by mature
silver maple (Acer saccharinum) trees which are starting to die back and there are not enough young trees in the
forest to replace them. The forest lacks young trees largely because of the regular flooding and the presence of reed
canary grass (Phalaris arundinacea), an invasive grass that grows in thick mats and inhibits the germination and
growth of tree seedlings. In addition to the loss of mature trees and the lack of young trees, forest diversity is also
declining because of dutch elm disease and the emerald ash borer (Agrilus planipennis) which kill the older elm
and ash that were once more common in these stands. These forests provide critical habitat for forest dependent
birds but without active management they will continue to decline in quality and quantity over time.
Our program is focused on managing invasive species and regenerating a variety of tree and shrub species to
improve bottomland forest habitat for birds. We prepared sites for planting or natural regeneration using
herbicide, disking, or mowing. We planted bare root tree seedlings, cottonwood cuttings, or direct seeded trees
including oaks and walnuts. We used tree tubes to protect trees from deer and voles; improved tree vigor and
growth through selective thinning; and controlled weeds through herbicide treatments and mowing after planting.
Our geographic scope included the Mississippi River from Hastings, MN to the Iowa border and the lower ends of
major tributaries. Much of this land in SE Minnesota includes state forests, Wildlife Management Areas, or National
Wildlife and Fish Refuge lands.
Our priorities were determined in cooperation with MN Department of Natural Resources, 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 manage
invasive species long enough to establish young trees that will be the future 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 the results, and apply that information to designing new projects.
A description of each project is provided below. For some sites additional work may be continued with Phase 3 and
Phase 4 of our floodplain forest enhancement program.
Cannon River Bottoms / Collischan South (30 acres)
This project was postponed in 2016 due to high water. A contractor treated 30 acres with herbicide during late
summer 2017, and then planted 5000 bare root (BR) silver maple seedlings and 2400 Root Production Method
(RPM) seedlings of silver maple, Ohio buckeye, river birch, Kentucky coffee tree, tulip tree, black gum, and
sycamore during fall 2017. The contractor planted an additional 4600 BR seedlings during spring 2018.
Reno Bottoms (60 acres)
At the north end of Reno Bottoms, a contractor girdled 162 trees and treated the cuts with herbicide. Patches of
reed canary grass were treated with herbicide and re-seeded with Virginia and Canada wild rye. Hardwood treesP a g e 3 | 11
were planted to maintain existing quality forest. In November 2018 a contractor planted RPM 50 Swamp White
Oak, 50 Kentucky Coffee Trees, and hand seeded 5 lbs. of button bush.
Richmond Island (10 acres)
At Richmond Island we reduced black locust density, and treated buckthorn and honeysuckle with herbicide in late
2017 and early 2018.
Root River (150 acres)
This project has multiple phases including herbicide treatments, site preparation, direct seeding, planting bare root
seedlings, planting RPM trees, planting cottonwood cuttings, timber stand improvement and post treatment weed
In fall of 2018 we planted 200 swamp white oak bare root seedlings into mounds 1 ft. high and 2 ft. wide. We also
planted 700 cottonwood cuttings, 550 swamp white oak RPM, an additional 1300 swamp white oak BR, 100
southern pin oak BR, and 50 bur oak BR. We also direct seeded 120 lbs. of swamp white oak acorns. In 2019 we
planted 500 swamp white oak RPM trees. We also direct seeded silky dogwood, red dogwood, grey dogwood,
nannyberry, and button bush. The Root River site will receive continued management in phase 3 and 4.
Wabasha Bottoms (100 acres)
We conducted a timber sale to enlarge gaps for tree planting. The harvest technique was used intentionally to
create openings for tree planting and natural regeneration. In the fall of 2018, the openings were treated with
herbicide. The gaps were planted with 2000 swamp white oak BR, 50 swamp white oak RPM, and 50 Kentucky
coffee tree RPM. Unfortunately, spring flooding in 2019 killed the bare root seedlings and the Kentucky coffee
trees. Within the southernmost harvested gaps, great silver maple regeneration was present, but did not persist.
Whalen (8 acres)
We completed multiple herbicide applications around trees planted in 2014 and 2015 to reduce competition with
reed canary grass. We conducted site preparation for future plantings including mowing and disking. We collected
cottonwood cuttings and planted 100 cottonwood spears. Unfortunately only 20% of the cottonwood planting
survived, but the trees that did survive are 20 feet tall healthy Cottonwood. We speculated that our source
population might not have been vigorous. By taking cuttings off the surviving cottonwood we hope to build a good
source of strong trees thatwe can continue harvesting from in the future.
Whitewater DNR (16 acres)
We applied an herbicide treatment during the summer of 2016 but the fall of 2016 was too wet to do second
herbicide treatment or to complete direct seeding. Herbicide was applied again during the summer/fall 2017. The
area was direct seeded in spring 2018 with 6 bushels of Swamp white oak, 6 bushels bur oak, 3 bushel red oak, 3
bushel white oak, 3 bushels bitternut hickory, and 3 bushels of shagbark hickory.
$412,000 the second year is to the commissioner of natural resources for an agreement with the National Audubon Society to restore and 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.
460 acres Forest enhancement .
USFWS, private donors, foundation grants, private donors, foundation grants