Preliminary temperature and soil moisture data-logger network for studying park vegetation

Fridley, Jason

"PI is developing high-resolution maps of temperature for the park, using a network of almost 200 dataloggers, most of which are in the Noland Creek and West Prong of the Little River watersheds. Besides elevation, cold air draining down streams is also important in the distribution of temperature throughout a watershed. 30-m resolution predictive maps of park-wide daily min and max temperature for this period are complete. Local topography (such as aspect stream proximity) and canopy cover, as they affect sun exposure, soil moisture, and cold air flow from higher elevations, have pronounced effects on min and max temperatures 1m above ground level, and uncouple certain components of annual temperature regimes from standard estimates based on elevation, a change of as much as 4 degrees C. Soil moisture is particularly important. Early indications are that high elevations may warm less than expected over the coming decades if high precipitation continues, with the greatest changes being expected at low elevations. From 2012 to 2013, PI and postdoc Mark Lesser worked to determine the interaction between ground level temperature, plant available nutrients, and plant available soil moisture across the park. Sensors were added to their six main transects, along the Old Sugarlands, Husky Gap, Road Prong, Beech Flats, Hyatt Ridge, and Beech Gap Trails. Pre-dawn leaf water potential along each transect on three occasions throughout the growing season. Soil water content data were also collected at the same time as the pre-dawn water potential measurements were made. Tree cores were collected from red spruce and red maple at each sensor site to analyze for growth and nutrient content of rings. Preliminary suggests that nutrient and moisture levels are strong constraints on tree growth, regardless of climate fluctuations. Ultimately, they hope to predict the fate of tree growth in different climate scenarios."