Controlling Reed Canarygrass (Phalaris Arundinacea) And Restoring Floodplain Forest In The Upper Mississippi River Valley

Abstract

Floodplain forest loss in the Upper Mississippi Valley is concerning because of the habitat these forests provide, especially for birds. Native floodplain forest systems are increasingly susceptible to reed canarygrass (Phalaris arundinaceae; RCG) establishment and spread. Once invaded by RCG, ecological restoration of floodplain requires integrated treatments that reduce the existing RCG population, along with additional long-term control measures. A common secondary measure is tree or shrub plantings to provide shade and reduce the competitive ability of this shade-intolerant invader. Chapter one builds on prior research that combines RCG control and reforestation, uniquely combining two herbicide treatments, two tree stock types (root production method “RPM,” and bare root), and four tree species. Species and stock type emerged as important factors in models of survival, growth, and deer browse. RPMs had greater survival, growth, and browse than bare roots under most conditions. Cottonwoods had the greatest height growth but the lowest survival. The top performing species was silver maple, which had both high survival and moderate growth. Our results suggest that land managers have flexibility for implementing RCG treatments but should consider their choice of stock type and species as it will affect tree survival and height outcomes. Chapter two explores sharing management recommendations from the restoration experiment with land managers. Our team is developing a decision support tool (DST) that will connect land managers with practical recommendations supported by research. To inform the creation of an effective DST, I conducted interviews with floodplain land managers in the Upper Mississippi River Valley. Despite diverse goals, all interviewees are interested in increasing native plant community coverage, particularly floodplain forests. Land managers are knowledgeable of and use many restoration techniques but they are still seeking more effective and efficient methods. They confirmed they do not get information from scientific journals, instead they are interested in materials that provide guidance on site assessment and management recommendations in an easy to understand format.