CU News
News from the University of Colorado in Boulder.
CU researchers: Beetle killed trees are better than logging for watersheds
Jan 14th
CU-led study shows pine beetle outbreak
buffers watersheds from nitrate pollution
buffers watersheds from nitrate pollution
A research team involving several scientists from the University of Colorado Boulder has found an unexpected silver lining in the devastating pine beetle outbreaks ravaging the West: Such events do not harm water quality in adjacent streams as scientists had previously believed.
According to CU-Boulder team member Professor William Lewis, the new study shows that smaller trees and other vegetation that survive pine beetle invasions along waterways increase their uptake of nitrate, a common disturbance-related pollutant. While logging or damaging storms can drive stream nitrate concentrations up by 400 percent for multiple years, the team found no significant increase in the nitrate concentrations following extensive pine beetle tree mortality in a number of Colorado study areas.
Beetle-killed forests do not release nitrogen into the water, according to CU researchers
“We found that the beetles do not disturb watersheds in the same way as logging and severe storms,” said Lewis, interim director of CU’s Cooperative Institute for Research in Environmental Sciences. “They leave behind smaller trees and other understory vegetation, which compensate for the loss of larger pine trees by taking up additional nitrate from the system. Beetle-kill conditions are a good benchmark for the protection of sub-canopy vegetation to preserve water quality during forest management activities.”
A paper on the subject was published in the Jan. 14 issue of the Proceedings of the National Academy of Sciences.
“The U.S. Forest Service and other agencies have established harvesting practices that greatly mitigate damage to forests caused by logging, and they deserve credit for that,” said Lewis. “But this study shows just how important the survival of smaller trees and understory vegetation can be to stream water quality.”
In waterways adjacent to healthy pine forests, concentrations of nitrate is generally far lower than in rivers on the plains in the West like the South Platte, said Lewis. Nitrate pollution is caused by agricultural runoff from populated areas and by permitted discharges of treated effluent from water treatment facilities.
“In Colorado, many watersheds have lost 80 to 90 percent of their tree canopy as a result of the beetle epidemic,” said Lewis, also a faculty member in CU-Boulder’s ecology and evolutionary biology department. “We began to wonder whether the loss of the trees was reducing water quality in the streams. We knew that forestry and water managers were expecting big changes in water quality as a result of the pine beetle outbreak, so we decided to pool our university and federal agency resources in order to come up with an answer.”
Study co-author and CU-Boulder Research Associate James McCutchan of CIRES said the new results should help forest managers develop more effective ways to harvest timber while having the smallest effect possible on downstream ecosystems. “This study shows that at least in some areas, it is possible to remove a large part of the tree biomass from a watershed with a very minimal effect on the stream ecosystem,” he said.
Understory vegetation left intact after beetle outbreaks gains an ecological advantage in terms of survival and growth, since small trees no longer have to compete with large trees and have more access to light, water and nutrients, said McCutchan. Research by study co-author and former CU undergraduate Rachel Ertz showed concentrations of nitrate in the needles of small pines that survived beetle infestations were higher than those in healthy trees outside beetle-killed areas, another indication of how understory vegetation compensates for environmental conditions in beetle kill areas.
The researchers used computer modeling to show that in western forests, such a “compensatory response” provides potent water quality protection against the adverse effects of nitrates only if roughly half of the vegetation survives “overstory” mortality from beetle kill events, which is what occurs normally in such areas, said Lewis.
Other study co-authors included Leigh Cooper, Thomas Detmer and Thomas Veblen from CU-Boulder, John Stednick from Colorado State University, Charles Rhoades from the U.S. Forest Service, Jennifer Briggs and David Clow from the U.S. Geological Survey and Gene Likens of the Cary Institute of Ecosystem Studies in Millbrook, N.Y.
The severe pine beetle epidemic in Colorado and Wyoming forests is part of an unprecedented beetle outbreak that ranges from Mexico to Canada. A November 2012 study by CU-Boulder doctoral student Teresa Chapman showed the 2001-02 drought greatly accelerated the development of the mountain pine beetle epidemic.
The researchers measured stream nitrate concentrations at more than 100 sites in western Colorado containing lodgepole pines with a range of beetle-induced tree damage. The study area included measurements from the Fraser Experimental Forest near Granby, Colo., a 23,000-acre study area established by the USFS in 1937.
The new study was funded by the USFS, the USGS, the National Science Foundation, the National Oceanic and Atmospheric Administration and the National Park Service. CIRES is a joint research institute between CU-Boulder and NOAA.
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Colorado business confidence remains positive going into first quarter, says CU Leeds School index
Jan 2nd
Colorado business leaders’ optimism is modest going into the first quarter of 2013 with uncertainty surrounding the country’s political and economic environments, according to the most recent quarterly Leeds Business Confidence Index, or LBCI, released today by the University of Colorado Boulder’s Leeds School of Business.
For the first quarter of 2013 the LBCI, conducted by the Leeds School’s Business Research Division, posted an overall confidence reading of 51.3, down slightly from 51.6 in the fourth quarter of 2012. A reading greater than the neutral mark of 50 indicates positive expectations and one less than 50 indicates negative expectations going forward
Business leaders are optimistic about all of the metrics of the quarterly index except for the national economy and industry hiring plans. The other categories measured include the state economy, industry sales, industry profits and capital expenditures.
“For months, drags on the national economy have included the European debt crisis, the slow rate of employment growth and the resolution of the federal debt crisis,” said economist Richard Wobbekind, executive director of the Business Research Division. “While Colorado business leaders have stronger confidence in the local economy than the national economy, they’re proceeding very cautiously.”
Confidence in the state economy, which is at 55.5 points for the first quarter of 2013, outstrips that of the national economy, which posted a reading of 47. The outpacing of confidence in Colorado’s economy compared to the national economy is a 30-quarter trend, based on LBCI results.
Business leaders’ sales expectations for the first quarter rose to 54.4, up from 53.2 last quarter, and are buoyed by 44.1 percent of LBCI respondents who anticipate an increase in the first quarter versus only 25.2 percent who predict a decline. Meanwhile, leaders’ profit expectations fell to 51.6, down from 52.2 for the last quarter of 2012.
Hiring expectations have slipped into negative territory at 49.3, down from 51 in the last quarter of 2012, while capital expenditures remain close to neutral at 50.1.
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CU-Boulder team develops swarm of pingpong ball-sized robots
Dec 14th
University of Colorado Boulder Assistant Professor Nikolaus Correll likes to think in multiples. If one robot can accomplish a singular task, think how much more could be accomplished if you had hundreds of them.
Correll and his computer science research team, including research associate Dustin Reishus and professional research assistant Nick Farrow, have developed a basic robotic building block, which he hopes to reproduce in large quantities to develop increasingly complex systems.
Recently the team created a swarm of 20 robots, each the size of a pingpong ball, which they call “droplets.” When the droplets swarm together, Correll said, they form a “liquid that thinks.”
To accelerate the pace of innovation, he has created a lab where students can explore and develop new applications of robotics with basic, inexpensive tools.
Similar to the fictional “nanomorphs” depicted in the “Terminator” films, large swarms of intelligent robotic devices could be used for a range of tasks. Swarms of robots could be unleashed to contain an oil spill or to self-assemble into a piece of hardware after being launched separately into space, Correll said.
Correll plans to use the droplets to demonstrate self-assembly and swarm-intelligent behaviors such as pattern recognition, sensor-based motion and adaptive shape change. These behaviors could then be transferred to large swarms for water- or air-based tasks.
Correll hopes to create a design methodology for aggregating the droplets into more complex behaviors such as assembling parts of a large space telescope or an aircraft.
In the fall, Correll received the National Science Foundation’s Faculty Early Career Development award known as “CAREER.” In addition, he has received support from NSF’s Early Concept Grants for Exploratory Research program, as well as NASA and the U.S. Air Force.
He also is continuing work on robotic garden technology he developed at the Massachusetts Institute of Technology in 2009. Correll has been working with Joseph Tanner in CU-Boulder’s aerospace engineering sciences department to further develop the technology, involving autonomous sensors and robots that can tend gardens, in conjunction with a model of a long-term space habitat being built by students.
Correll says there is virtually no limit to what might be created through distributed intelligence systems.
“Every living organism is made from a swarm of collaborating cells,” he said. “Perhaps some day, our swarms will colonize space where they will assemble habitats and lush gardens for future space explorers.”
For a short video of Correll’s team developing swarm droplets visit http://www.colorado.edu/news/multimedia/researchers-creating-team-tiny-robots. For more information about CU-Boulder’s computer science department visit http://www.colorado.edu/engineering/academics/degree/computer-science.
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