Posts tagged trees
The Flower Bin is proud to have been serving local gardeners for 41 years. They grow most of their own plants! The ‘Bin has been helping gardeners of all ages and experience levels fill their gardens and homes with locally-grown options for any occasion.
Phone: (303) 772-3434
Weekdays: 8 a.m. to 7 p.m.
Saturday: 8 a.m. to 6 p.m.
Sunday: 9 a.m. to 6 p.m.
Temporary lane closures for tree removals along Arapahoe Avenue rescheduled for Monday, April 15
With a winter storm warning in effect for Boulder, the tree removal work that was planned for Tuesday, April 9, and Friday, April 12, has been rescheduled to April 15 due to the inclement weather forecast.
On Monday, April 15, there will be intermittent lane closures in both directions on Arapahoe Avenue between 18th and 19th streets from 9 a.m. to 3:30 p.m. Contractors working for the City of Boulder Urban Forestry Division will be removing three high-risk trees in preparation for the upcoming Arapahoe Avenue Reconstruction project. The two-lane section of Arapahoe Avenue, between Folsom and 17th streets, is in poor condition and in need of a reconstruction.
During the tree removals, traffic will be directed into the center lane. The work schedule is weather-dependent.
In the 1800 block of Arapahoe Avenue, two silver maple trees with significant trunk cavities and restricted root zones will be removed for safety reasons. In the 2100 block, a Siberian elm will be removed due to past storm damage. These are the only large trees planned for removal as part of the Arapahoe Avenue Reconstruction. The city has contacted adjacent property owners in advance and will explore opportunities to plant replacement trees.
The city’s Urban Forestry Division inspects street trees in neighborhoods and parks for structural integrity and safety using industry-set standards and techniques. For more information about the tree removals, contact Patrick Bohin with the Urban Forestry Division at 303-519-8750 or watch the video at vimeo.com/63247248.
The Arapahoe Avenue Reconstruction project includes reconstruction of the street into concrete, storm drainage improvements, and sidewalk, bus stop, and landscaping improvements, as space and funding allow.The reconstruction is planned to begin in late May 2013 and will be completed in fall 2013. The project is funded by the 2011 voter-approved Capital Improvement Bond, which allowed the city to leverage existing revenues to bond for approximately $49 million to fund projects that address significant deficiencies, such as this one, and high priority infrastructure improvements. A community stakeholder committee prioritized projects to be funded by the bond and Arapahoe improvements were given a high priority due to current deteriorating conditions.
For more information about the Arapahoe Avenue Reconstruction project, contact Noreen Walsh at 303-441-3266 or visit www.bouldertransportation.net > “Projects & Programs” > “Arapahoe Avenue.”
The City of Boulder Parks and Recreation Department’s Urban Forestry Division will require temporary lane closures around Boulder in the next few weeks to remove a number of large trees. Forestry staff has determined that these trees pose a public safety hazard due to internal decay, structural weakness and/or large dead branches overhanging streets, sidewalks and structures. This is routine work. Dates are tentative and weather-dependent.
On Monday, Feb. 25, there will be intermittent closures of Balsam Avenue between 14th and 15th streets from noon to 3:30 p.m.
On Wednesday, Feb. 27, there will be intermittent closures of Norwood Avenue between 21st Street and Norwood Court from 8:30 to 11:30 a.m. Also on Feb. 27, the outside lane of northbound Broadway, north of Norwood Avenue, will be closed from noon to 3:30 p.m.
On Thursday, Feb. 28 and Friday, March 1, the southbound lane of Airport Road will be closed from 8 a.m. to 4 p.m. Southbound traffic will be directed into a center lane.
On Monday, March 4, the southbound and right turn lane of Spine Road will be closed north of Lookout Road from 8:30 to 11 a.m. All southbound and turning traffic will be directed through the left turn lane. Also on March 4, there will be intermittent closures of Merritt Drive from Ingersoll Place to Holmes Place between noon and 3:30 p.m.
On Tuesday, March 5, there will be intermittent closures of 55th Street between Blackhawk Road and Tenino Avenue from 9 to 11:30 a.m. Also on March 5, the outside westbound lane of South Boulder Road will be closed from noon to 3 p.m. west of Manhattan Drive.
On Sunday, March 10, the westbound lane of Valmont Road between 28th Street and 30th Street will be closed from 9 a.m. to 3 p.m.
In addition to these tree removals requiring lane closures, contractors working for the Urban Forestry Division will remove two other large trees with significant cavities in their trunks and/or major branches. These include the following:
- A cottonwood tree at the Main Boulder Public Library, 1001 Arapahoe Ave., with a large trunk cavity.
- A silver maple tree at 1743 Mapleton Ave. with large cavities in its major branches
City park and neighborhood street trees are inspected annually for structural integrity and safety by the Urban Forestry Division using industry-set standards and techniques. For more information, contact the Urban Forestry office, 303-441-4406, Monday through Friday from 7 a.m. to 3:30 p.m.
CU-led study shows pine beetle outbreak
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.
“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.
Boulder Channel 1 visits the Flower Bin in Longmont to learn from owner Don Weakland about their huge holiday inventory and what makes them popular during the Christmas season, including wreaths, Christmas trees, and especially their wonderful selection of Poinsettias. We learn a little bit about the history of the Poinsettia plant and how they can be a great decoration for your holiday home setting along with the wide selection of other flowers and holiday ornaments and decorations in the shop.
Boulder County, Colo. – A forest thinning project at Heil Valley Ranch Open Space began on Friday and will continue until June. The Boulder County Parks and Open Space Department has hired a local contractor to mechanically treat approximately 150 acres of ponderosa pine forest.
Visitors to the open space property will likely hear the operations along the Wapiti Trail and Ponderosa Loop during the next eight months. Visitors must stay on-trail to protect their safety and that of the equipment operators.
Like so many ponderosa pine forests, the area is unnaturally dense due to years of fire suppression. This forestry project will create a mosaic of openings and uneven-aged groupings of trees. The goal is to have a healthier forest that is less susceptible to insects, disease or catastrophic wild fires. The treatment involves the use of two primary machines; a harvester that fells, delimbs, and bucks the tree into standard log lengths, and a forwarder to haul wood material off-site.
For additional information, contact Forest Specialist Nick Stremel at 303-678-6290 or firstname.lastname@example.org.
A new University of Colorado Boulder study shows for the first time that episodes of reduced precipitation in the southern Rocky Mountains, especially during the 2001-02 drought, greatly accelerated development of the mountain pine beetle epidemic.
The study, the first ever to chart the evolution of the current pine beetle epidemic in the southern Rocky Mountains, compared patterns of beetle outbreak in the two primary host species, the ponderosa pine and lodgepole pine, said CU-Boulder doctoral student Teresa Chapman. The current mountain pine beetle outbreak in the southern Rockies — which range from southern Wyoming through Colorado and into northern New Mexico –is estimated to have impacted nearly 3,000 square miles of forests, said Chapman, lead study author.
While the 2001-02 drought in the West played a key role in pushing the pine beetle outbreak into a true regional epidemic, the outbreak continued to gain ground even after temperature and precipitation levels returned to levels nearer the long-term averages, said Chapman of CU-Boulder’s geography department. The beetles continued to decimate lodgepole pine forests by moving into wetter and higher elevations and into less susceptible tree stands — those with smaller diameter lodgepoles sharing space with other tree species.
“In recent years some researchers have thought the pine beetle outbreak in the southern Rocky Mountains might have started in one place and spread from there,” said Chapman. “What we found was that the mountain pine beetle outbreak originated in many locations. The idea that the outbreak spread from multiple places, then coalesced and continued spreading, really highlights the importance of the broad-scale drivers of the pine beetle epidemic like climate and drought.”
A paper on the subject was recently published in the journal Ecology. Co-authors on the study include CU-Boulder geography Professor Thomas Veblen and Tania Schoennagel, an adjunct faculty member in the geography department and a research scientist at CU-Boulder’s Institute of Arctic and Alpine Research. The National Science Foundation funded the study.
Mountain pine beetles are native insects that have shaped the forests of North America for thousands of years. They range from Canada to Mexico and are found at elevations from sea level to 11,000 feet. The effects of pine beetles are especially evident in recent years on Colorado’s Western Slope, including Rocky Mountain National Park, with a particularly severe epidemic occurring in Grand and Routt counties.
Chapman said the most recent mountain pine beetle outbreak began in the 1990s, primarily in scattered groups of lodgepole pine trees living at low elevations in areas of lower annual precipitation. Following the 2001-02 drought, the outbreak was “uncoupled” from the initial weather and landscape conditions, triggering a rise in beetle populations on the Western Slope and propelling the insects over the Continental Divide into the northern Front Range to infect ponderosa pine, Chapman said.
The current pine beetle epidemic in the southern Rocky Mountains was influenced in part by extensive forest fires that ravaged Colorado’s Western Slope from roughly 1850 to 1890, said Chapman. Lodgepole pine stands completely burned off by the fires were succeeded by huge swaths of seedling lodgepoles that eventually grew side by side into dense mature stands, making them easier targets for the pine beetles.
“The widespread burning associated with dry years in the 19th century set the stage for the current outbreak by creating vast areas of trees in the size classes most susceptible to beetle attack,” said Chapman.
Veblen said a 1980s outbreak of the pine beetle centered in Colorado’s Grand County ended when extremely low minimum temperatures were reached in the winters of 1983 and 1984, killing the beetle larvae. But during the current outbreak, minimum temperatures during all seasons have been persistently high since 1996, well above the levels of extreme cold shown to kill beetle larvae in laboratory experiments.
“This implies that under continued warming trends, future outbreaks will not be terminated until they exhaust their food supply — the pine tree hosts,” said Veblen.
Chapman said there has been a massive and unprecedented beetle epidemic in British Columbia, which also began in the early 1990s and has now has affected nearly 70,000 square miles. “It is hard to tell if this current beetle epidemic in the Southern Rockies is unprecedented,” she said. “While warm periods in the 16th century may have triggered a large beetle epidemic, any evidence would have been wiped out by the massive fires in the latter part of the 19th century.”
Veblen said while the rate of spread of the mountain pine beetle in lodgepole pine forests has declined in the southern Rocky Mountains during the past two years because of a depletion of host pine population, U.S. Forest Service surveys indicate the rate of beetle spread in ponderosa pine forests on the Front Range has increased sharply over the past three years. “The current study suggests that under the continued warmer climate, the spread of the beetle in ponderosa pines is likely to grow until that food source also is depleted,” Veblen said.
“Our results emphasize the importance of considering different patterns in the population dynamics of mountain pine beetles for different host species, even under similar regional-scale weather variations,” said Chapman. “Given the current outbreak of mountain pine beetles on the Front Range, their impact on ponderosa pines is certainly something that needs further study.”
A 2012 study by CU-Boulder Professor Jeffry Mitton and graduate student Scott Ferrenberg showed some Colorado pine beetles, which had been known to produce only one generation of tree-killing offspring annually, are producing two generations per year due to rising temperatures and a longer annual warm season. Because of the extra annual generation of beetles, there could be up to 60 times as many beetles attacking trees in any given year, according to the study.
In addition, a 2011 study led by CU-Boulder graduate student Evan Pugh indicated the infestation of trees by mountain pine beetles in the high country across the West could potentially trigger earlier snowmelt and increase water yields from snowpack that accumulates beneath affected trees.
Residents encouraged to secure trash and food sources to protect bears
With bears foraging for food in preparation for their winter hibernation, it is important that residents take measures to deter bears by securing any potential food sources on their properties. See the Inside Boulder News segment about recent bear activity.
Bear-proofing food items and trash is the best way for residents to minimize the chance that bears will show interest in their property. Common bear attractants include garbage, compost, fruit from trees, bird feeders, food from outdoor grills and pet food left outside.
City regulations require that curbside garbage/compost bins not be placed out for pick up until 5 a.m. the day collection occurs. Alleyway bins are exempt from these regulations.
To be safe, the city recommends that residents west of Broadway store all garbage and compost bins in a garage or shed until the morning of collection, or keep their waste in a bear-resistant trash container. Residents within Boulder city limits can contact their trash hauler for specific information about bear-resistant trash containers.
Bears that learn that people are a source of food are sometimes killed to keep the public safe. During the past six years, Colorado Parks and Wildlife has killed five bears in Boulder because of nuisance behavior or a threat to public safety. Please do your part to ensure that bears are not unnecessarily attracted to your property.
If there is a bear in your backyard, the following tips are recommended:
- Keep your distance. Back away slowly from the bear, ensuring it has a clear escape path;
- Never run. Running may cause a bear to chase you;
- Never approach a bear, or get in between a cub and its mother;
- Never provide food to a bear. This teaches it to approach people for food;
- Do not let the bear become comfortable around your home; and
- Once you are safely inside, do your best to scare the bear away. Yell, clap your hands and make other loud noises to encourage the bear to leave.
If the bear is observed within the city limits, call the Boulder Police Department at 303-441-3333. To report past bear sightings and encounters, call 303-441-3004.
The city is currently conducting an Urban Black Bear Education and Enforcement Pilot Program in partnership with Colorado Parks and Wildlife. For more information about the pilot program, contact Urban Wildlife Conservation Coordinator Val Matheson at 303-441-3004 or visit www.boulderwildlifeplan.net.
For a detailed discussion about bears in the urban/foothill interface, watch the “Bears in Boulder” segment of A Boulder View.
City of Boulder Open Space and Mountain Parks officials today announced the re-opening of the Bear Canyon Trail following last week’s fire closure. Bear Canyon Trail above west of the Mesa Trail will be open, effective immediately, up to where hikers can connect to Green Mountain via the Green-Bear Trail. Travel is limited to on-trail only. Fern Canyon, Bear Peak West Ridge and Shadow Canyon trails remain closed.
Because much of the area that burned is on very steep slopes, contained very large trees, and was largely inaccessible to fire crews, some areas of active fire may continue to smolder for some time. Dangerous conditions continue to exist, especially along the eastern edge of the fire and in Fern and Shadow canyons.
“We had a spot fire in upper Shadow Canyon,” Stone said, “and smoldering trees can topple over and ignite at any time. Burning logs and debris can roll downhill on such steep slopes and start new fires. So we still have to be somewhat cautious about opening all of the area around the fire even though these areas may not actually have burned.”
Open Space and Fire Department staff will continue to assess the fire potential and risks to the public over the next few weeks. The city will strive to strike a reasonable balance between risk and access to these popular natural areas.
A map of the continued closures is attached to this release.
For information, visit www.osmp.org or call 303-441-3440.
Tree removals in early July to impact traffic along the Boulder Creek Path and West Pearl Street
There will be minor and temporary traffic impacts as the City of Boulder Parks and Recreation Department’s Urban Forestry Section will have a contractor pruning and removing trees for safety reasons from Monday, July 2, through Tuesday, July 10 (dates are tentative, as work is weather dependent).
On Monday, July 2, between 8 a.m. and 4 p.m. and Tuesday, July 3, between 8 a.m. and noon, a large cottonwood with advanced decay will be removed at 646 Pearl St.—the historic Arnett-Fullen house. The eastbound lane of Pearl Street will be closed in the 600 block and flaggers will be used to channel traffic into the westbound lane of Pearl Street on an alternating basis. The property owners are aware of, and in support of, the tree removal for safety reasons. There is a large beehive in the trunk, and as per normal operations, a beekeeper has been contracted to attempt to relocate the beehive during tree removal. A replacement tree has already been planted near this tree’s location.
Tree removals along the Boulder Creek Path include:
● Thursday, July 5, between 8 a.m. and 4 p.m.: Two large willow trees will be removed south of Boulder High School, 1604 Arapahoe Ave. One tree is mostly dead and the other tree fell over earlier this year.
● Friday, July 6, between 8 a.m. and 4 p.m.: One large cottonwood tree will be removed on the west side of 6th Street, south of the Boulder County Justice Center, 1777 6th St. The tree has advanced decay. A replacement tree will planted nearby in spring of 2013.
● Monday, July 9 between 8 a.m. and 2 p.m. and Tuesday, July 10, between 8 a.m. and noon: Two large willow trees will be removed west of Scott Carpenter Park, 1505 30th St. Both trees have advanced decay in their trunks.
There will be intermittent closures on the Boulder Creek Path, and flaggers will be used to direct bicycle and pedestrian traffic through work zones.
For more information, please contact the City of Boulder Park Operations and Urban Forestry: 303-441-4406.
The Tree Farm is known throughout the Rocky Mountain Region as a most extraordinary place. As Colorado natives, the Spahn Family has strove since 1980 to satisfy the demands of the most discriminating consumers with our unique nursery.
Phone: (303) 652-2961
Monday – Saturday: 8 a.m. to 6 p.m.
Sunday: 10 a.m. to 4 p.m.
Boulder County, Colo. – Boulder County residents ages 14-17 have until Friday, March 30 to apply for summer jobs with the Boulder County Youth Corps. Boulder County is especially in need of female corps members.
The Youth Corps will hire up to 160 teenagers to work 30 hours per week, Monday through Thursday, from June 18 to Aug. 8 on a variety of community service projects such as forest thinning, historic preservation, construction and repair of fencing, trail maintenance, removal of Russian olive trees and noxious weeds, landscaping and replacing light bulbs with compact fluorescents. Youth Corps teams will work in unincorporated Boulder County as well as in Lafayette, Longmont and Superior.
Applications are available online at www.bouldercounty.org/youthcorps. Applications can also be picked up at counseling offices in Boulder Valley and St. Vrain Valley schools; city and town personnel offices; most local recreation and youth centers and libraries; and the Boulder County Human Resources Department at 2025 14th St. in Boulder.
Corps members will earn a starting wage of $7.64 per hour, with the possibility of earning a $100 bonus at the end of the program based on merit and strong attendance. Teens who have worked for the corps in past years can earn up to $8.14 an hour. In addition, corps members are eligible for reimbursement for the purchase of work boots and gloves. RTD bus passes for the purpose of traveling to and from centralized work meeting places may be subsidized.
The Youth Corps offers one of the best first job opportunities available in Boulder County. Teams have completed projects such as building the new Fourmile Trail connector at Betasso Preserve Open Space and preserving the historically significant lower barn at Walker Ranch Open Space.
For more information, visit www.bouldercounty.org/youthcorps or call the Youth Corps office at 303-678-6104.
Discovery of pine beetles breeding twice in a year
helps explain increasing damage, CU researchers say
Long thought to produce only one generation of tree-killing offspring annually, some populations of mountain pine beetles now produce two generations per year, dramatically increasing the potential for the bugs to kill lodgepole and ponderosa pine trees, University of Colorado Boulder researchers have found.
Because of the extra annual generation of beetles, there could be up to 60 times as many beetles attacking trees in any given year, their study found. And in response to warmer temperatures at high elevations, pine beetles also are better able to survive and attack trees that haven’t previously developed defenses.
These are among the key findings of Jeffry Mitton, a CU-Boulder professor of ecology and evolutionary biology, and Scott Ferrenberg, a graduate student in that department. The study is being published this month in The American Naturalist.
This exponential increase in the beetle population might help to explain the scope of the current beetle epidemic, which is the largest in history and extends from the Sangre de Cristo Mountains in New Mexico to the Yukon Territory near Alaska.
“This thing is immense,” Mitton said. The duo’s research, conducted in 2009 and 2010 at CU’s Mountain Research Station, located about 25 miles west of Boulder, helps explain why.
“We followed them through the summer, and we saw something that had never been seen before,” Mitton said. “Adults that were newly laid eggs two months before were going out and attacking trees” — in the same year. Normally, mountain pine beetles spend a winter as larvae in trees before emerging as adults the following summer.
These effects may be particularly pronounced at higher elevations, where warmer temperatures have facilitated beetle attacks. In the last two decades at the Mountain Research Station, mean annual temperatures were 2.7 degrees Fahrenheit warmer than they were in the previous two decades.
Warmer temperatures gave the beetle larvae more spring days to grow to adulthood. The number of spring days above freezing temperatures increased by 15.1 in the last two decades, Mitton and Ferrenberg report. Also, the number of days that were warm enough for the beetles to grow increased by 44 percent since 1970.
The Mountain Research Station site is about 10,000 feet in elevation, 1,000 feet higher than the beetles have historically thrived. In their study, Mitton and Ferrenberg emphasize this anomaly.
“While our study is limited in area, it was completed in a site that was characterized as climatically unsuitable for (mountain pine beetle) development by the U.S. Forest Service only three decades ago,” they write.
But in 25 years, the beetles have expanded their range 2,000 feet higher in elevation and 240 miles north in latitude in Canada, Mitton said.
Ferrenberg had the idea to monitor the beetles at higher elevations partly because trees at lower elevations have been attacked by beetles for centuries and have developed some defenses.
Lodgepole pines at higher elevations tended to have a lower density of resin ducts, which transport resin, the sole defense against beetles. The number of resin ducts in a tree can be a “marker” for whether a tree has a higher or lower resistance to a beetle attack, Ferrenberg said.
The trees at higher elevations had not faced the same intensity of beetle attacks as those at lower elevations until temperatures warmed, and they have not faced pressures of natural selection exerted by attacking beetles. “The trees in that area are somewhat naïve in their response,” Ferrenberg said.
These data help explain why westbound motorists emerging from the Eisenhower Tunnel on I-70 can look up, from 11,000 feet in elevation, and see beetle-killed trees. “We think we see some of the reason for the fact that this epidemic is so widespread,” Mitton said.
The research was funded by the U.S. Department of Energy.
More on this story will appear in the next edition of Colorado Arts and Sciences Magazine at http://artsandsciences.colorado.edu/magazine/
Source: Colorado Arts and Sciences Magazine
Gasoline worse than diesel when it
comes to some types of air pollution
The exhaust fumes from gasoline vehicles contribute more to the production of a specific type of air pollution — secondary organic aerosols — than those from diesel vehicles, according to a new study by scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences, or CIRES, NOAA’s Earth System Research Laboratory and other colleagues.
“The surprising result we found was that it wasn’t diesel engines that were contributing the most to the organic aerosols in L.A.,” said CIRES research scientist Roya Bahreini who led the study and also works at the National Oceanic and Atmospheric Administration’s ESRL. “This was contrary to what the scientific community expected.”
SOAs are tiny particles that are formed in air and make up typically 40-60 percent of the aerosol mass in urban environments. This is important because fine-particle pollution can cause human health effects, such as heart or respiratory problems.
Due to the harmful nature of these particles and the fact that they can also impact the climate and can reduce visibility, scientists want to understand how they form, Bahreini said. Researchers had already established that SOAs could be formed from gases released by gasoline engines, diesel engines and natural sources — biogenic agents from plants and trees — but they had not determined which of these sources were the most important, she said.
“We needed to do the study in a location where we could separate the contribution from vehicles from that of natural emissions from vegetation,” Bahreini said.
Los Angeles proved to be an ideal location. Flanked by an ocean on one side and by mountains to the north and the east, it is, in terms of air circulation, relatively isolated, Bahreini said. At this location, the scientists made three weekday and three weekend flights with the NOAA P3 research aircraft, which hosted an arsenal of instruments designed to measure different aspects of air pollution.
“Each instrument tells a story about one piece of the puzzle,” Bahreini said. “Where do the particles come from? How are they different from weekday to weekend, and are the sources of vehicle emissions different from weekday to weekend?”
From their measurements, the scientists were able to confirm, as expected, that diesel trucks were used less during weekends, while the use of gasoline vehicles remained nearly constant throughout the week. The team then expected that the weekend levels of SOAs would take a dive from their weekday levels, Bahreini said.
But that was not what they found.
Instead, the levels of SOA particles remained relatively unchanged from their weekday levels. Because the scientists knew that the only two sources for SOA production in this location were gasoline and diesel fumes, the study’s result pointed directly to gasoline as the key source.
“The contribution of diesel to SOA is almost negligible,” Bahreini said. “Even being conservative, we could deduce from our results that the maximum upper limit of contribution to SOA would be 20 percent.”
That leaves gasoline contributing the other 80 percent or more of the SOA, Bahreini said. The finding was published online March 1 in Geophysical Research Letters. “While diesel engines emit other pollutants such as soot and nitrogen oxides, for organic aerosol pollution they are not the primary culprit,” Bahreini said.
If the scientists were to apply their findings from the L.A. study to the rest of the world, a decrease in the emission of organic species from gasoline engines may significantly reduce SOA concentrations on a global scale as well. This suggests future research aimed at understanding ways to reduce gasoline emissions would be valuable.
The study was funded by NOAA’s Climate Change and Air Quality Programs, the California Air Resources Board and the National Science Foundation.
CIRES coauthors on the team include Joost de Gouw, Carsten Warneke, Harald Stark, William Dube, Jessica Gilman, Katherine Hall, John Holloway, Anne Perring, Joshua Schwarz, Ryan Spackman and Nicholas Wagner.
Wednesday Jan 18 8:15pm Boulder police and fire report numerous traffic lights out over the city. Serveral transformers are being reported blown and on fire.
A tree fell on power line near 11 and Walnut starting a fire.
Nearby homes were evacuated.
In east boulder cattle fences blew down and cattle were on highway.
RTD is reporting some large signs down in city.
City 911 very busy. Dispatch reports
Power outages all over city.
Wind related roll over accidents 2 in last hour.
Some officers have been seen wearing helmets and googles. Good advice to anyone walking around. See weather report below. This does not account for the foothills of Boulder where winds are high
8:20 pm Power lines down on Pennsylvania on hill
8:25pm Tree down at 9th and college impeding traffic
Tiles flying off down town church at Broadway and Spruce
8:45pm Boulder County reports power line down in field at redwood court, sparking with fire and embers.
all fires out at this point, but police report signs, debris flying through air. Power lines are down and there are still power outages.
9:00pm Boulder Airport reports constant wind speed of 54mph Various sources in city report gusts of 71mph to 92mph
Diagonal and Look out road RR crossing sign blew into car causing tow car accident.
9:27pm Boulder Weather Station live reposts Power lines and trees continue to fall at this hour.
High Wind Warning
.HIGH WINDS IN THE MOUNTAINS AND FOOTHILLS THROUGH THURSDAY MORNING…
.VERY STRONG WEST WINDS WILL CONTINUE OVER THE NORTHERN COLORADO
MOUNTAINS…FOOTHILLS AND ADJACENT PLAINS THROUGH THURSDAY
MORNING. THE HIGH WIND WARNING IN THE MOUNTAINS HAS BEEN UPGRADED TO A
BLIZZARD WARNING FOR THE REST OF TONIGHT AS SNOW WILL DEVELOP ALONG
WITH THE CONTINUED WIND.
WIND GUSTS FROM 70 TO 90 MPH WILL BE COMMON IN WIND PRONE
MOUNTAIN AND FOOTHILL AREAS…AND ALSO IN FAVORED AREAS JUST EAST
OF THE MOUNTAINS SUCH AS ROCKY FLATS…BOULDER…AND CARTER LAKE.
THE STRONG WINDS WILL LIKELY CAUSE DOWNED TREES…POWER OUTAGES…
AND MAY BLOW OVER HIGH PROFILE AND LIGHT WEIGHT VEHICLES.
MONITOR THE LATEST WEATHER CONDITIONS AND AVOID TRAVEL IN AREAS
EXPERIENCING VIOLENT WINDS. MAIN AREAS LIKELY TO BE AFFECTED ARE
INTERSTATE 70 IN JEFFERSON AND CLEAR CREEK COUNTIES…THE PEAK TO
PEAK HIGHWAY BETWEEN BLACK HAWK AND ESTES PARK…AND HIGHWAYS AT
THE BASE OF THE FOOTHILLS.