Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Old Logging Practices Linked to High Erosion Rates

21.10.2010
Clear-cut logging and related road-building in the 1950s and 1960s in southern Oregon's Siskiyou Mountains disrupted soil stability and led to unprecedented soil erosion made worse during heavy rainstorms, report University of Oregon researchers.

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
The University of Oregon is a world-class teaching and research institution and Oregon's flagship public university. The UO is a member of the Association of American Universities (AAU), an organization made up of the 63 leading public and private research institutions in the United States and Canada. The UO is one of only two AAU members in the Pacific Northwest.

Contact: Jim Barlow, director of science and research communications, 541-346-3481, jebarlow@uoregon.edu

Sources: Daniel Gavin, assistant professor of geography, 541-346-5787, dgavin@uoregon.edu; Daniele Colombaroli, postdoctoral researcher, Oeschger Centre for Climate Change Research and Institute of Plant Sciences, University of Bern, +41 31 631 49 85; daniele.colombaroli@ips.unibe.ch

Links:
Daniel Gavin homepage: http://geography.uoregon.edu/gavin/gavin.html
UO Department of Geography: http://geography.uoregon.edu/
University of Bern Institute of Plant Sciences – Section Paleoecology : http://www.ips.unibe.ch/paleo/index.php

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
Further information:
http://www.uoregon.edu

More articles from Earth Sciences:

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>