NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/695082
JULY 2016 • NEBRASKAland 41 By Carissa Wonkka, Dirac Twidwell and Dave Wedin, University of Nebraska W e are part of a team of University of Nebraska researchers pondering the impacts of the eight large wildfires that have burned in the Pine Ridge since 1989. Among the questions we are seeking answers to: 1) what is the present status and future of the ponderosa pine in the Pine Ridge? 2) how have the fires influenced the region's rare plants? 3) are the fires promoting non-native plants? And most importantly, can we limit the damage of future wildfires? Here are some of our early findings. Satellite photos after a wildfire can be used to measure the severity of its impacts to soils and vegetation. Previously, researchers from the Wildland Fire Leadership Council used such photos to determine the relative damage the eight wildfires caused to ponderosa pine forests in the Pine Ridge. Areas within a wildfire's perimeter where most large pines were killed were classified as high-severity fires, areas where roughly half the large pines were killed were labeled moderate-severity fires, and areas that did not burn or where only few large pines were killed were minimal-severity fires. This past year, we analyzed the Pine Ridge fire severity maps and found some interesting results. Though it is often assumed that wildfires severely burn and destroy the entire pine forest, we found the severity of the Pine Ridge fires ranged widely. More than 15 percent of ponderosa forest was severely burned in only four of the eight wildfires. The highest proportion was during the 2006 Sioux Fire where 35 percent of the forest was severely burned, followed by 28 percent during the 1989 Fort Robinson Fire, 20 percent during the 2007 Soldier Creek Fire and 17 percent during the 2012 Wellnitz Fire. Within a wildfire's perimeter, it was far more likely for pine stands to escape the fire or be exposed to minimal damage than to be severely burned. Interestingly, though the 2012 wildfires burned more area, they were less severe than the previous fires. A major concern for ranchers and conservationists is the establishment and spread of non-native invasive plants on their land after wildfires. Last summer, we conducted extensive inventories for cheatgrass, smooth brome and non-native thistles in the Pine Ridge to determine the wildfires' impact on these unwanted species. We found that fire severity did not influence the chance of their invasion. Time since a wildfire, however, influenced their distribution and abundance with older fires generally having fewer of these invasive plants, meaning native vegetation recovers well after a fire given time. Cheatgrass is the most prevalent invasive plant across the Pine Ridge, occurring in 67 percent of sampled plots. ■ Pine Ridge Wildfire Research This stand of ponderosa pine survived the 2012 wildfire with little damage. PHOTO BY GERRY STEINAUER PHOTO BY GERRY STEINAUER