While logging practices have improved dramatically since then, the damaged landscape -- the removal of low vegetation that helps to protect hillsides during fires and rain -- continues to pose a threat into the foreseeable future, said Daniel G. Gavin, professor of geography, and postdoctoral doctoral researcher Daniele Colombaroli.
Their research -- funded by the Swiss National Science Foundation and the UO -- involved the analyses of charcoal, pollen and sediment taken from 30-foot-deep cores drilled below Upper Squaw Lake in the Rogue River-Siskiyou National Forest. Their findings, which provide a look at the impacts of fires over the last 2,000 years, appeared online Oct. 18 in the Early Edition of the Proceedings of the National Academy of Sciences. The data, which provided for greater scrutiny than that of tree-ring records, allowed the researchers to analyze conditions at different time periods and compare soil conditions during fire and flooding events over time.
"There is a legacy of poor logging practices conducted decades ago," Gavin said. "Road building during that period was done with little concern for subsequent erosion. The soils were much more heavily impacted by that development compared to the prehistoric fires of the past. Our study shows that at least four times more erosion occurred on the landscape after the logging and floods of the 1960s compared to the most severe prehistoric fire. So we are dealing with a more delicate, less-resistant ecosystem in the majority of areas that has seen this logging."
Over much of the last 2,000 years, according to pollen records, soils in the forests of the region were naturally resilient, maintaining their abundance, through periods of drought, severe fire and moderate erosion events, the researchers noted. "This resiliency was reduced by road building, logging and major floods," they wrote.
That legacy of mid-century logging, said Colombaroli, a native of northern Italy who now is at the University of Bern in Switzerland, may be more of a concern than the occurrence of severe fires, which are strongly affected by climate. "Fire is known now to be a natural component of the ecosystem, but it is not clear whether forests are able to quickly recover after intense fire if logging practices altered the natural dynamics of the forest, and if the hazard of severe fire can be reduced by, for example, controlled burnings," Colombaroli said.
Gavin and Colombaroli had sought to understand whether forests in this region have been subject to severe fire events before the 1800s, or whether light, low-intensity burns were typical. This information would place some severe fires in recent years, such as the 196,000-hectacre Biscuit Fire in 2002, into a longer-term context. The results pointed to a highly episodic pattern of fire, with periods of frequent fire during widespread and severe periods of drought (A.D. 900-1300) alternating with long periods with little fire (A.D. 1500-1800).
The 2000-year record shows how fire and erosion were linked in the past, and how some fires hundreds of years ago were severe enough to cause distinct erosion on hillsides.
“With data obtained on both the pattern of fire and erosion," Gavin said, "it's clear that severe fire is not a new threat to these forests, but what is a new to these forests is the logging-related erosion levels and the current species composition. How the current forest responds to severe fire, therefore, may differ from that in the past.
The findings, the authors noted, suggest that management strategies might well include approaches aimed at returning public forests to their natural resiliency to help reduce damage levels from fire and erosion. However, Gavin said, these particular findings should be considered place-specific.
"They don't apply widely throughout Oregon's forests," he noted. "The site is on the Oregon-California border, and is representative of what's called mixed conifer -- pines mixed with trees with shorter needles, especially Douglas-fir. This mix is common in southwest Oregon and northwest California, from I-5 west to near the coast."About the University of Oregon
Contact: Jim Barlow, director of science and research communications, 541-346-3481, firstname.lastname@example.org
Sources: Daniel Gavin, assistant professor of geography, 541-346-5787, email@example.com; Daniele Colombaroli, postdoctoral researcher, Oeschger Centre for Climate Change Research and Institute of Plant Sciences, University of Bern, +41 31 631 49 85; firstname.lastname@example.orgLinks:
Oeschger Centre for Climate Change Research: http://www.oeschger.unibe.ch/
Follow UO Science News via Facebook: http://www.facebook.com/UniversityOfOregonScience
Jim Barlow | Newswise Science News
Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation
Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences