Hyperspectral Data Analysis of Whitebark Pine (Pinus albicaulis) and White Pine Blister Rust (Cronartium ribicola) at Four Sites in the Greater Yellowstone Ecosystem

Halligan, Kerry; Crabtree, Robert; Jones, Matthew

Whitebark pine (Pinus albicaulis) is a species of high interest in the Greater Yellowstone Area (GYA) due to its ecological importance as well as the challenges it currently faces. Whitebark pine (WBP) grows in cold, snowy and moderately moist climates where it is commonly found on ridges and near timberline on rocky, well-drained sites. In Montana WBP is found from 5,900 to 9,300 ft and in Wyoming it occurs from 7,300 to 10,500 feet. It provides important habitat for many species and is a significant food source for birds, small mammals, and grizzly bears. Unfortunately, WBP is threatened by white pine blister rust (Cronartium ribicola) throughout its range including the GYA. The survival of the grizzly bear will be affected if the majority of WBP in the Yellowstone region is lost due to this introduced disease. At present, the only information readily available pertaining to WBP distribution and health are maps derived from air photo interpretation and ground surveys of blister rust incidence. The labor and logistical costs of these approaches limit their application over the large areas occupied by WBP in the GYA. Observer variability bias and the quality limitations of air photos and their subjective interpretation further complicate regional and ecosystem-wide efforts. There is a critical need for cost-effective assessment and monitoring tools that are accurate, efficient, and ready for deployment for managers at regional and ecosystem scales. The overriding purpose of this project is to develop and assess reliable remote sensing methods capable of mapping the condition and distribution of WBP. If successful, then GYA-wide surveys from fixed-wing aircraft or satellites might be conducted. However, before any such large-scale efforts are pursued it is important to conduct a feasibility study of a promising remote sensing approach—high resolution hyperspectral (HRHS) imaging and data analysis. HRHS has recently been used to conduct highly accurate surveys of ecological variables previously unattainable with traditional remote sensing approaches (see Crabtree et al., in press). Thus, this feasibility study proposed to provide the following specific objectives: (1) a detailed map of WBP condition, including the observed symptoms of healthy green, incipient flagging or chlorotic stress, red needle flagging, and dead (branches and snags), (2) a detailed map of WBP distribution including the percent composition of WBP versus other conifer species, and (3) general recommendations with regard to field methods and approaches, accuracy, spatial scale, costs, and detection limits for future ecosystem-wide efforts.