It all depends on the type of vegetation in the area.
A new study on the cover of the May issue of Ecological Monographs shows that, in some cases, the types of plants growing in an area could override the effects of climate change on wildfire occurrence.
Lawrence Livermore National Laboratory scientist Tom Brown along with Philip Higuera of Montana State University and colleagues looked at the direct and indirect impacts of millennial scale climate change on fire occurrence in the south-central Brooks Range in Alaska.
The team looked at historical fire occurrence by analyzing sediments found in the bottom of lakes.
Using the Lab’s Center for Accelerator Mass Spectrometry, they carbon dated the deposits in the sediment and reconstructed fire occurrences from 15,000 B.C. to the present. They then measured the amount of plant parts, such as fossil pollen, to figure out what type of vegetation dominated the area during the different time periods. Like rings in a tree, different layers of sediment represent different times in the past.
The conclusion: historical changes fire frequencies coincided with changes in the type of vegetation in the area, more so than to rising temperatures alone.
“If all we did was look at rising temperatures and ignore the vegetation in the area, that wouldn’t be a good predictor of the likelihood of wildfires in a particular region,” Brown said. “You have to look at the whole picture.”
Although changing temperatures and moisture content set the stage for changes in wildfire frequency, they can often be trumped by changes in the distribution and abundance of plants.
Earlier studies have shown that the area burned across arctic and boreal regions will increase over the next century as climate change lengthens the fire season, decreases moisture and increases ignition rates. However, vegetation can alter the direct link between climate and fire by influencing the abundance, structure and moisture content of fuels across space and time, Brown said.
“There’s a complex relationship between fuels and climate,” he said. “Vegetation can have a profound impact on fire occurrences that are opposite or independent of climate’s direct influence on fire.”
In the recent study, the researchers found that changes in climate were less important than changes in vegetation. Despite a transition from a cool, dry climate to a warm, dry climate about 10,500 years ago, the researchers found a sharp decline in the frequency of fires. Their sediment cores from that time period revealed a vegetation change from flammable shrubs to fire-resistant deciduous trees.
“In this case, a warmer climate was likely more favorable for fire occurrence, but the development of deciduous trees on the landscape offset this direct climatic effect,” Higuera said.
The research implies that the impacts of climate change on modern-day fire frequencies could be strongly mediated by changes in vegetation. Thus, in some cases, the impacts of climate change on fire may be less intuitive than initially perceived.
“This could give fire managers a good indication that vegetation can substantially alter the direct effects of climate change on fire occurrence,” Brown said.
Other contributors include the University of Washington and the University of Illinois-Urbana.
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
Anne Stark | EurekAlert!
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy