Rings and Rasters: Groundwater access impacts on tree productivity in the Central Sands of Wisconsin

Keywords: Wisconsin, Central Sands, groundwater, LIDAR, dendrochronology, trees, agriculture, ecosystems, Red Pine, Pinus resinosa, forests, depth-to-groundwater, aquifer, plantations
Session Type: Virtual Poster Abstract
Day: Sunday
Session Start / End Time: 2/27/2022 02:00 PM (Eastern Time (US & Canada)) - 2/27/2022 03:20 PM (Eastern Time (US & Canada))
Room: Virtual 38

Abstract

Groundwater influences numerous ecosystems across the Central Sands Region of Wisconsin, with competing water-use interests being central to policy debates over its regulation. This is exemplified by the growing tensions between advocates for agricultural irrigation and groundwater-fed trout streams. However, a third stakeholder, natural forests and pine plantations, may also be affected by water-use decisions, with broad implications for the region’s forests. Here, we investigated the impacts of groundwater access on forest productivity in red pine (Pinus resinosa) plantations at two sites in the Central Sands that spanned depth-to-groundwater gradients. We documented tree diameter, height, and annual growth rates and combined these data with LIDAR-derived canopy height and a regional depth-to-groundwater model to quantify how access to groundwater affects forest productivity. We found identified significant correlations between each variable and depth-to-groundwater, linking access to groundwater to forest and potentially ecosystem-scale productivity. Furthermore, we found variations in the depth-to-groundwater over time modulated climate-growth relationships. These findings suggest that future discussions about groundwater utilization in the Central Sands of Wisconsin should include potential impacts on forest ecosystems and carbon sequestration as well as aquatic and agricultural systems when considering the potential impact of groundwater withdrawals and regional depth-to-ground conditions. Based on documented declines in Central Sands aquifers, extraction of groundwater for agricultural purposes may impact forest productivity at a regional scale.