Determining reference conditions for ecosystem management of southwestern ponderosa pine forests

The fire disturbance regime and forest structure prior to Euro-American settlement (AD 1883) of a southwestern ponderosa pine (Pinus ponderosa) landscape were quantified in order to establish reference conditions as a baseline for ecosystem management. The mean presettlement fire interval between 1637 and 1883 was 3.7 yr for all fires and 6.5 yr for widespread fires, but fire has been excluded from the study area since 1883. Forest density increased under fire exclusion from an average of 148 trees/ha in 1883 (65 pines, 80 oaks, three other species), an open forest dominated by relatively large ponderosa pines, to 1265 trees/ha in 1994/1995 (720 pines, 471 oaks, 74 others), a dense forest characterized by relatively small and young trees. Species composition has shifted toward greater dominance by Gambel oak (Quercus gambelii) and conifers less adapted to frequent fires: white fir (Abies concolor) and Douglas-fir (Pseudotsuga menziesii). The reference presettlement conditions can be applied to management of this ecosystem in two ways. First, reference conditions are a benchmark against which to evaluate contemporary conditions and future alternatives. The comparison shows that the contemporary forest is well above the range of presettlement variability in forest density, and both live and dead fuel structures have developed that can support high-intensity wildfire. Second, reference conditions can serve as a goal for ecological restoration treatments

Landscape Assessment and Monitoring of Mountain Pine Beetle Mortality in Greater Yellowstone Ecosystem Whitebark Pine

Since 2000, USDA Forest Service Aerial Detection Surveys (ADS) and ground-based surveys indicate mountain pine beetle (MPB) outbreaks have caused catastrophic loss of whitebark pine (WBP) in the Greater Yellowstone Ecosystem (GYE). However, the full extent of the damage is unknown because of limitations to the traditional survey methods. We describe a new method aimed at quickly and cost-effectively documenting landscape conditions. The method utilizes low-flying airplane overflights, Global Positioning System (GPS), and Geographic Information System (GIS) technologies along with digital photography to categorize MPB outbreaks based on a new landscape classification scheme. We conducted a pilot study consisting of four overflights covering large portions of the Teton Wilderness, Wind River, Absaroka, Gallatin, and Beartooth mountain ranges. Results indicate our approach is a reliable and repeatable method to assess the extent and severity of MPB related WBP mortality. Significant MPB activity was documented throughout the area surveyed - only the center core of the Wind River Range, the Beartooth Plateau and Northern Gallatin Range remain in a healthy condition. A vast area of approximately 450,000 acre covering the northern Wind River Range, Southwestern Absoroka Range and the Teton Wilderness, was found to be the most heavily impacted. Here the overflights document an ecological collapse of the WBP ecosystem due to unprecedented MPB outbreaks. This pilot study provided an independent validation of previous computer simulations and corroborates the general trend indicated by US Forest Service ADS. Additionally, results extend previous information in several ways: (1) The outbreaks are outpacing computer simulations that were based on climate warming predictions. (2) Our approach identified greater mortality when compared to the ADS results. (3) Overflights were conducted in several regions of the GYE not recently or never surveyed by ADS, and therefore provide a more comprehensive documentation of MPB impact in WBP than previously available