The Cannon River flows through the Lower Arb, and its floodplain supports a distinctive biological community. Some parts of the floodplain apparently were never cleared (such as the forest in D8; see inset map of 1931 land use), but large portions of the floodplain were cultivated for many decades. Agricultural areas were removed from cultivation in 1970, 1982, and 1990; there is currently no farming in the floodplain.
Once these fields were abandoned, the process of ecological succession proceeded relatively rapidly. For instance, a farm field (H13-14) was abandoned as part of the celebration of the first Earth Day in 1970. Though many trees were planted in this field by volunteers at that time, mortality of saplings was very high. Luckily, there is ample nearby seed source for the appropriate floodplain trees such as cottonwoods (Populus deltoides), silver maple (Acer saccharinum), and willows (Salix spp.); these species have recruited successfully and a forest of young trees is rapidly approaching maturity. Relatively little intervention will be needed to produce a floodplain forest in the 1982 and 1990 Fields, and succession can be allowed to proceed naturally. Once back in forest cover, the Arb’s floodplains will help in the management of Cannon River flooding by acting as a buffer to rapid changes in water level and by holding the soil during flood periods.
To learn more about the trees in this area, and how to identify them, visit the Common Floodplain Tree Guide.