Adaptive Silviculture in an urban floodplain forest: exploring functional traits and soil responses for climate ready forests

Floodplain forests within the Mississippi National River and Recreation Area (MNRRA) are experiencing numerous ecological challenges related to altered hydrology, land use changes, introduced species, and climate change. One of the most pressing concerns is the loss of the predominant canopy species, green ash (Fraxinus pennsylvanica), due to predation by emerald ash borer (EAB) (Agrilus planipennis). This change in stand structure has resulted in canopy gaps increasingly being filled by forbs, shrubs, or other species considered weedy, competitive, and a hindrance to tree regeneration. Additionally, climate and habitat suitability models project that tree species currently found within MNNRA's floodplain forests will see a reduction in suitable habitat within the region, further underscoring the need to identify suitable replacements able to restore a mature closed canopy. To address these challenges, the Adaptive Silviculture for Climate Change (ASCC) network has established silvicultural trials in the floodplain forest at Crosby Farm Regional Park (CFRP) to explore adaptive management strategies that will provide insight into integrating climate change adaptation into silvicultural planning and on-the-ground actions. The treatments within CFRP ASCC were designed to test climate-adaptive communities composed of species and seed sources from local and more southern hardiness zones. Now in its fifth year, a core set of response variables, including growth and mortality, have provided a glimpse into how different tree species respond to assisted migration, community composition, and floodplain dynamics. However, the underlying mechanisms driving these trends remain unclear. In an attempt to identify these underlying mechanisms, we have measured the photosynthetic performance, water relations, and foliar nutrients of the individuals and communities in the experiment. In addition to exploring tree ecophysiology, we also measured soil moisture and temperature dynamics at multiple depths to assess whether the experimental treatments that vary in species composition influence below-ground conditions. We found that community composition had no effect on volumetric water content (VWC) or soil temperature. However, depth had a significant effect, with VWC increasing and temperature decreasing with depth. Community-weighted trait means revealed treatment differences in gas exchange, nutrient content, and leaf water status, with the resilience treatment showing higher photosynthetic activity and the transition treatment favoring traits typically associated with resource acquisition. Together, these results contribute mechanistic insight into tree performance and provide land managers with information to guide restoration efforts within MNRRA's floodplain forests successfully.

Author dc:creator

• Glenn-Stone, Catherine

• Adaptive Management
• Ecophysiology
• Forest Ecology
• Forestry
• Silviculture

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/11299/277963

OAI identifier oai:identifier

oai:conservancy.umn.edu:11299/277963