The forests of the Mississippi River have been shaped throughout time by different geologic processes. Throughout the history of the Mississippi River Valley, indigenous peoples had a minimal impact on the forested resource of the river. Most use was in the way of food, primarily acorn, and firewood collection. The first major impact on the River's forest resources was westward expansion of the USA in the early 1800's. As settlers flocked to the riverbank settlements, they utilized the timber along the River to build these booming river towns. Millions of logs were floated down the River from the great pine forests of the northern woods to the mills in the River towns. Steamboats increased the flux of people to the River valley. These steamboats used tremendous amounts of wood as fuel to power their steam engines. A traveler through the region commented on this in the mid-1800's: "...steamboats on the Mississippi all burn wood, and such are the immense quantities destroyed in this manner that had not nature provided an inexhaustible supply, some other fuel would have had long since to take its place." - Henry Lewis, a traveler, 1848.
Forest and prairie clearing also took place in the River bottom for agricultural purposes to take advantage of the rich alluvial soils. A significant amount of land was cleared for crop ground in the Mississippi River Valley. As early as the 1830's, the Federal Government, aware of the upper river's important role in the settlement of the Mississippi Valley, began improvements in the interest of navigation., The first such works consisted of the removal of the most menacing snags, shoals, and sand bars; the dynamiting and excavation of rock in several reaches of rapids to clear a passage; and the closing off of meandering sloughs and backwaters to confine flows to the main channel and thus assure more adequate depths for navigation in times of low water.
In 1878 Congress authorized The Four and a Half-Foot Navigation Project to circumvent the many shallow places and rapids in the River. This included construction of short lateral canals with navigation locks around the most serious rapids. The Six Foot Navigation Project followed in 1907, which included the construction of hundreds of rock and brush wing dams. The Nine-Foot Navigation Project was authorized in 1930. This involved the building of 28 Locks and Dams. It also involved the acquisition of 193,311 acres in the St. Paul, Rock Island and St. Louis Districts for project operations, most of which would be flooded on a regular basis. Approximately 1/3rd to ½ of those acres are permanently flooded. The rest is managed by the Corps for different objectives.
At the time of acquisition, significant floodplain acreages were farm fields and pasture. Most of this was abandoned, which then naturally seeded to forests. The trees that took over these sites were pioneer and opportunistic species such as silver maple and cottonwood. The wind dispersed seed from these species allowed them to quickly capture and vegetate these sites. A large portion of the remaining land that was forested was high-graded, cutting out all valuable timber, prior to condemnation by the Government.
The Corps forestry program was started in 1941. An early goal was to support the World War II effort. The Corps of Engineers was then given the authority by the Secretary of War to meet the demand for various forest products which were used for making war goods such as shipping boxes, crates, pallets and building materials. Millions of board feet of cottonwood and silver maple were sold by competitive bid to local timber buyers. Plans called for all trees above a certain diameter to be cut. Hard mast producing trees such as oaks and hickories were considered important for their wildlife food value. These hard mast trees were only cut when there was adequate regeneration under the existing canopy. This selective cutting program continued until the late 1960's.
In 1963 the Corps entered into a cooperative agreement with the US Fish and Wildlife Service. The Corps made available to the FWS 163,324 acres of land and water areas of the Navigation Channel Project for the conservation, maintenance, and management of wildlife resources thereof, and its habitat thereon, in connection with the national migratory bird management program. These areas became part of the Upper Mississippi River National Wildlife and Fish Refuge, Port Louisa National Wildlife Refuge, Great River National Wildlife Refuge, and Two Rivers National Wildlife Refuge. In addition, the Fish and Wildlife Service has outgranted some of this land to the respective state resource agencies. Some lands were made available directly to state natural resource agencies as well. The early forest management plan led to high-grading of much of the forests in the Mississippi River Floodplain, a condition that takes the best trees for timber and leaves the poorer trees. With greater environmental awakening in the 1970's a new forestry plan was developed, and implemented starting in 1981 by the Corps and its' cooperating agencies. This new plan is the current method of partnership and cooperation that focuses on maintaining the integrity of the whole ecosystem.