Mapping and Monitoring Mountain Pine Beetle Outbreaks in Whitebark Pine Ecosystems with Satellite Imagery

Whitebark pine ecosystems are currently subjected to multiple threats, including extensive outbreaks of mountain pine beetle in recent years. These infestations have killed substantial numbers of trees in the Central and Northern Rocky Mountains, including in the Greater Yellowstone Ecosystem and in Idaho. Monitoring outbreaks in these rugged, mountainous regions for ecological studies is facilitated by spatially extensive remotely sensed imagery. Here we report on studies using a variety of satellite imagery to map pine mortality resulting from infestations of mountain pine beetle, with a focus on whitebark pine forests. We will discuss methods for classifying tree mortality using fine spatial resolution QuickBird imagery at Railroad Ridge, Idaho. Masking and maximum likelihood classification methods were developed to partition the landscape into non-vegetated, green herbaceous, brown herbaceous, live tree, and dead tree classes. We assessed the accuracy of this classification using an independent set of image pixels as well as field measurements of live and dead trees; high accuracies were achieved. We will also report on methods to utilize moderate-resolution (Landsat) and coarse-resolution (MODIS) satellite imagery to map tree mortality with single- and multi-date methods. We will illustrate the ecological use of classified imagery by assessing spatial and temporal dynamics of the imagery as well as the distribution of mortality with respect to topographic variables