Satellite images highlighted by NASA this week reveal a massive forest die-off in Colorado due to severe pine park beetle infestations.
NASA posted two images — one from September 11, 2005 and the other from September 28, 2011 — to show the impacts of the beetles. NASA describes the changes:
“Over six years, beetle activity turned entire ridges and valleys brown,” writes NASA’s Adam Voiland. “Forest die-off is most visible in the center of the image and along both sides of the Kawuneeche Valley. The brownest areas in the 2011 image are generally stands of lodgepole pine, a slender tree that grows at 6,000 to 11,000 feet (1,800 to 3,300 meters) in elevation. Either spruce or aspen dominates the green areas that escaped infestation, such as the forests near Gravel Mountain and areas west of the Kawuneeche Valley.”
Acquired September 11, 2005. NASA Earth Observatory image created by Robert Simmon, using Landsat data provided by the United States Geological Survey.
NASA noted that logging contribute to some of the observed change.
NASA added that while beetle infestations are often blamed for creating conditions that exacerbate forest fires, it cited Colorado State University professor Bill Romme in arguing that the link may not be as strong as some believe.
“Most research indicates that there is little or no such relationship between beetle-caused tree mortality and subsequent fire occurrence and severity in lodgepole pine forests,” Romme was quoted as saying. “Fire occurrence and severity in these forests are controlled primarily by weather conditions. Variation in fuel conditions, such as that introduced by the beetles, is a secondary and generally minor influence on fire behavior.”
Acquired September 11, 2005. NASA Earth Observatory image created by Robert Simmon, using Landsat data provided by the United States Geological Survey.
NASA said the most intense fires tend to jump between tree crowns, rather than burning dry pine needles dropped on the forest floor after beetle infestations.
“For the first few years after an infestation, beetle-impacted forests may have an increased risk of crown fires due to the dry needles that remain clinging to the tops of dying trees,” writes Voiland. “But as these needles—and other debris—drop to the ground, the risk of crown fires drops as well. According to one study, forest die-off from pine beetles infestations can reduce the risk of crown fires for decades by thinning forests.”
Thomas Veblen, another University of Colorado professor, told NASA the underlying factor behind an increase in forest fires in the Western United States is warming climate conditions.
“While dead trees from pine beetles provide a teachable moment for discussing fire hazard, the underlying factor explaining the increase in area burned across the western U.S.—which is well documented—since the 1980s is warming,” he said.
Related articles
