Counting marmots…
The large objective of this project is to clarify the how environmental and community factors condition subalpine forest responses to climate extremes. Subalpine forests are outsize contributors to the hydrological budget of the Rocky Mountains, but they are exposed to increasing water and temperature stresses associated with climate change. Prior research in these systems has not adequately described the seasonally varying relationships between plant-available water, atmospheric demand, and tree growth. To address these knowledge gaps, I aim to (1) maintain an existing sensor network monitoring soil volumetric water content (?), temperature, conductivity, and atmospheric fluxes to evaluate spatial and temporal variability in soil water dynamics; and (2) to conclude an ongoing dendrochronology campaign seeking to quantify how tree growth rates vary over space and time, across species, and with the instrumented climate record of the watershed. My proposed research is motivated by three core expectations: (1) where water availability is the limiting factor in tree productivity, moisture deficit will be associated with low growth, but there may be other limiting factors present (radiation, pests, or pathogens) that override water limitation; (2) to sustain productivity, trees alternate uptake between shallow and deep water sources where possible and may also redistribute water to replenish dry pools; (3) water availability and plant water use vary across sites as a function of precipitation input, soil properties, and species traits. This effort will shed needed light on the coupling vegetation dynamics and hydrology in headwater forests.