Complex dynamics underlie bark beetle eruptionsJune 02, 2008Climate change and biological processes at large and small scales drive outbreaks now killing forests in the American West Forest management that favors single tree species and climate change are just two of the critical factors making forests throughout western North America more susceptible to infestation by bark beetles, according to an article published in the June 2008 BioScience. Bark beetle epidemics have become more extensive and frequent in recent years as winter temperatures have risen, and an eruption of mountain pine beetles is currently devastating lodgepole pines throughout the mountainous West. The article, by Kenneth F. Raffa of the University of Wisconsin at Madison and colleagues at Colorado State University, the University of Idaho, and the US and Canadian Forest Services, stresses the complexity of the biological processes that determine when a bark beetle eruption will occur. When beetles bore through a tree's bark, they release pheromones that summon other beetles to join the offensive. Trees counter attacks by exuding resin that can kill the invaders, but if too many beetles attack a weak tree, its defenses fail. The beetles then reproduce within its living tissues, with the help of colonizing fungi, and the tree is doomed. The condition and spacing of nearby trees and the local climate affect whether the beetle progeny released after a successful attack sustain an epidemic--which can kill a high proportion of the trees in an area and so alter the landscape for decades. Because many of the processes in an epidemic operate at different scales and turn on critical thresholds, prediction is a challenge. It is nonetheless clear that human activities can exacerbate bark beetle eruptions, which cause major economic losses and reduce forests' ability to absorb carbon from the atmosphere. American Institute of Biological Sciences |
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| Related Bark Beetle Current Events and Bark Beetle News Articles Biosphere 2 experiment shows how fast heat could kill drought-stressed trees Widespread die-off of piñon pine across the southwestern United States during future droughts will occur at least five times faster if climate warms by 4 degrees Celsius, even if future droughts are no worse than droughts of the past century, scientists have discovered in experiments conducted at the University of Arizona's Biosphere 2. Research ties tree mortality trends to climate warming Global warming is speeding up the mortality of trees, and NAU research is providing some of the data to prove it. New study links western tree mortality to warming temperatures, water stress A new study led by the U.S. Geological Survey and involving the University of Colorado at Boulder indicates tree deaths in the West's old-growth forests have more than doubled in recent decades, likely from regional warming and related drought conditions. Lichens function as indicators of nitrogen pollution in forests Scientists have found lichens can give insight into nitrogen air pollution effects on Sierra Nevada and San Bernardino mountain ecosystems, and protecting them provides safeguards for less sensitive species. UBC discovery unlocks tree genetics, gives new hope for pine beetle defense UBC researchers have discovered some of the genetic secrets that enable pine and spruce trees to fight off pests and disease, uncovering critical new information about forests' natural defense systems. Researchers discover key gene involved in bark beetle pheromone production University of Nevada, Reno scientists have ended a decade-long controversy over the process by which bark beetles make pheromones: they manufacture their own monoterpenes - the fragrant substances plants produce and which are often used in perfumes. Saving Trees by Stemming Beetles International efforts to protect forests have been given a boost by a unique information initiative headed by a University of Ulster scientist. Leading a four-year project compiling research by 100 European scientists, Coleraine-based researcher Dr Keith Day has co-edited a landmark publication providing essential information aimed at saving trees from bark-devouring insects, some of which transmit virulent fungi such as Dutch elm disease. More Bark Beetle Current Events and Bark Beetle News Articles |
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