American Forests helped leverage National Park Service (NPS) funding in the Greater Yellowstone Area (GYA) to estimate the Available Water Supply (AWS) for the 176 long-term whitebark pine monitoring sites. NPS personnel had previously started gathering data in 2013, but limited funding paused the project.

Many people — including project lead David Thoma, an hydrologist with the National Park Service — were enlisted by American Forests to coordinate the new AWS estimate project. The team also included Dr. Henry Shovic has proven local experience and expertise in soils, soil interpretations, soil survey, scientific analysis and documentation, remote sensing, and geo-spatial analysis. He has recently completed preliminary work on AWHC and AWS for Yellowstone National Park and the GYA, and has already compiled large amounts of necessary soils data, as well as having completed this work for 60 whitebark pine long-term monitoring sites.

We asked Thoma some questions about the project:

Q: What were some of the major goals for soil testing in the Greater Yellowstone Ecosystem?
A: We use information about soil properties to help understand how much water is available to trees and for how long. This property of soil, called water holding capacity, is especially important in dry years. The goal of this project was to obtain estimates of water holding capacity at the stand level in remote areas. This in turn helps us understand how trees respond to forest disease agents like mountain pine beetle, which are more lethal to trees when trees are drought stressed.

Q: Were there any startling or hopeful discoveries?
A: Our preliminary results suggest that the water supply for trees, which is affected by soil properties, is important for determining the probability of tree mortality if the tree was attacked by mountain pine beetle.

Q: How do you see this information being used? How is it most beneficial?
A: This information can be used by managers to select planting sites in the Greater Yellowstone Area according to soil properties that will increase the probability of tree survival, even when trees are attacked by mountain pine beetle.

Thoma, D., K. Irvine, H. Shovic, E. Shanahan, K. Legg 2014. Climatic controls on mountain pine beetle mediated mortality in whitebark pine in the GYE. Oral presentation at the Yellowstone Biennial Science Conference, Oct 6-8 Mammoth, WY.