Researchers find tree-bark thickness is affected by fire occurrence

The researchers found that the bark thickness of closely related species is linked to whether the species lived in a fire-prone or non-fire-prone region, which provided further evidence that bark thickness is an evolutionary adaptation to fire.

Above: firefighters mop up hot spots near a residence on the Eiler Fire in northern California, August 6, 2014. Photo by Bill Gabbert.

Researchers have determined that the thickness of bark on a tree can be affected by the frequency of fires within the region. Findings released in a paper today suggest that bark thickness could help predict which forests and savannas will survive a warmer climate in which wildfires are expected to increase in frequency.

Trees in regions where fire is common, such as savannas and the forests of western North America, tend to have thicker bark, while trees in tropical rainforests have thinner bark, researchers at Princeton University and collaborating institutions reported Jan. 11 in the journal Ecology Letters. Bark protects the inside of the trunk from overheating and is one of a handful of adaptations that trees use to survive fire.

“We found large-scale evidence that bark thickness is a fire-tolerance trait, and we showed this is the case not just in a particular biome such as a savanna, but across different types of forests, across regions and across continents,” said first author Adam Pellegrini, a NOAA Climate and Global Change Postdoctoral Fellow at Stanford University who led the study while a graduate student in Princeton’s Department of Ecology and Evolutionary Biology.

The research suggests that the link between bark thickness and fire resistance should be included in global climate models, Pellegrini said. “Trees from regions that burn frequently could still become vulnerable if the risk of fire increases,” he said. “The open question is whether the bark is thick enough to help trees survive.”

Pellegrini and his colleagues looked at 572 tree species in regions across the globe. They compared bark thickness from trees in areas that experience frequent wildfires — and where rain falls only seasonally — to trees in regions where fires are rare, such as tropical rainforests. They found that in areas where fires are frequent, most trees, no matter the species, have thicker bark than closely related tree species growing in low-fire areas.

The study suggests that tropical rainforests — which are mostly composed of thin-barked trees — may have a more difficult time recovering from fire, whereas savannas and seasonal forests with thickly barked trees should be able to better withstand fire. A savanna was defined as land with continuous grass cover that is 20 to 80 percent trees, while a forest was defined as having complete tree coverage and little to no grass.

Periodic fires are necessary for the health of some types of savannas and forests. Fires burn off excess plant matter such as dead wood and grass — as well as competing fire-sensitive species — and rejuvenate the soil so that the dominant, fire-resistant plant species can flourish. However, fires also can be detrimental to the environment by releasing stored carbon back into the atmosphere, and causing the decades-long loss of a valuable carbon-storage system.

North Pole Fire
North Pole Fire, west of Custer, South Dakota March 10, 2015. Photo by Bill Gabbert.

The researchers also addressed the question of where thick-barked trees come from: Did they evolve to have thick bark in response to living in a fire-prone region, or do thick-barked trees come from plant families with species that all tended to develop thick bark irrespective of fire activity? Continue reading “Researchers find tree-bark thickness is affected by fire occurrence”

747 SuperTanker receives federal approval

Above: The 747 Supertanker conducts a test drop at Colorado Springs May 4, 2016. Photo by Bill Gabbert.

(This article first appeared on Fire Aviation.)

The 747 SuperTanker has received interim approval from the Interagency Airtanker Board (IAB) according to Jennifer Jones, a spokesperson for the U.S. Forest Service. Jim Wheeler, President and CEO of Global SuperTanker, the operator of the air tanker, said he first heard from the IAB on January 6 that the approval had been granted.

Interim approval is the last step before full approval. It means the company can compete for and receive contracts to serve as an air tanker for federal agencies in the United States. If it receives a contract, the performance and effectiveness of the aircraft will be evaluated while under this status. Then if satisfactory, it can be elevated to full approval. The interim approval is valid through June 15, 2017, Mrs. Jones said.

When the Neptune Aviation BAe-146s were first converted to air tankers they were given “interim” status while bugs in the new system were found and eventually mitigated. For example, the company added additional drop doors farther forward on the fuselage in order to improve the dispersal of retardant while making a downhill drop.

However the retardant delivery system on this 747 has been used on previous 747s and was fully certified by the IAB years ago. Over the last year it has been installed in a 747-400 which has more powerful engines than the 747-100 and 747-200 used by Evergreen, the company that first built a 747 air tanker. Global Supertanker bought the hardware and intellectual property for the retardant system when Evergreen declared bankruptcy.

The 747 can hold 19,200 gallons, much more than any other air tanker. For comparison, the DC-10 very large air tanker carries 11,600 gallons, while the BAe-146, RJ85, and C-130 hold up to 3,000 to 3,500 gallons. The P2V Korean War vintage aircraft that has been the workhorse air tanker for decades usually carries less than 2,000 gallons. The S-2T used by CAL FIRE holds up to 1,200 gallons.

Last summer the 747 Supertanker received a Supplemental Type Certificate from the FAA and the agency’s Federal Aviation Regulations Part 137 certificate.

T-944 mountain flying
Global Supertanker.

In November it made a non-stop flight to Israel and after arriving dropped on two wildfires at the request of the country’s government.

“IAB approval is an essential requirement in airtanker contracts for some wildfire agencies, including the U.S. Forest Service (USFS),” Mr. Wheeler said. “With this approval, we look forward to bidding on – and winning – upcoming domestic and international contracts. We are grateful and excited to join the team of airtankers currently serving a critical mission for the United States and globally, and look forward to continuing to work with the USFS, CAL FIRE, and the IAB during the final approval process.”

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Atmospheric river brings extreme wind and precipitation to northern California

Atmospheric river
Atmospheric river funnels moist tropical air into northern California.

The atmospheric river of moist tropical air being funneled into northern California continues to dump very large amounts of precipitation in areas suffering from five years of drought.

The rain began Wednesday, January 4 and is predicted to continue at least into Wednesday of this week. Some areas have received between 5 and 9 inches of precipitation since Friday.

Atmospheric river extreme precipitation
Storm total precipitation in selected northern California locations, 5 p.m. Friday 1/6 through 5 p.m. Sunday 1/8.

The National Weather Service office in Reno, Nevada reported that multiple wind sensors recorded gusts Sunday morning that exceeded 170 mph.

Atmospheric river extreme wind
Extreme winds gusting above 170 mph were reported by the National Weather Service office in Reno, Nevada, Sunday January 8, between 6:45 a.m. PST and noon. Posted by the NWS at about noon local time on Sunday.

Some areas in the Sierra Nevada mountains could see another 3 to 7 inches of precipitation between Monday and Wednesday. Flooding is being reported in many areas.

Atmospheric river extreme precipitation
Precipitation forecast for northern California Monday 1/9 through Wednesday 1/11.

National Park Service officials evacuated the valley in Yosemite National Park Friday except for essential personnel.

Continue reading “Atmospheric river brings extreme wind and precipitation to northern California”

Wildfires burn millions of acres in Argentina

Most of the fires are in the provinces of La Pampas, Rio-Negro, and Buenos Aires.

Wildfires in Argentina have burned approximately 2.47 million acres (1 million hectares) over the last several weeks. On December 22 NASA satellites started detecting heat from fires that grew to become some of the larger blazes on the east side of the country 90 miles (145 kilometers) west of the coastal city of Bahia Blanca.

Fires Argentina
Fires detected by NASA satellites in Argentina December 22, 2016.

Below is an excerpt from an article by NASA, and following that is a series of five more satellite photos showing the progression of the fires up through January 6:

Severe drought during the winter and spring of 2016 in northeastern Patagonia played a large role in the current fires, said Guillermo Defossé, a professor of ecology at the National University of Patagonia San Juan Bosco and researcher for the Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), an organization that monitors Patagonian forests.

“While historically these ecosystems were fire prone, during the last century the number of wildfires severely declined as a consequence of a great grazing pressure—grazers consumed all fine fuels that otherwise will carry the fires—and a successful policy of fire exclusion,” Defossé wrote in an email. “This masked, in part, the fact that these ecosystems are naturally highly flammable, with a fire recurrence time of about 20–25 years. During the last 10 years, however, a very sharp decline in wool prices and continuous drought—probably due to climate change—made several ranchers to reduce the number of sheep or directly abandon the ranching activity. This abandonment increased the availability and amount of fine fuels.”

Fires Argentina
Fires detected by NASA satellites in Argentina December 27, 2016.

Continue reading “Wildfires burn millions of acres in Argentina”

Wildfire potential, January through April

With huge amounts of rain and snow hammering California and Oregon, few people in those areas are thinking about wildfires this week.

But in spite of the rain delivered to the west coast on what meteorologists are calling an “atmospheric river”, on January 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for January through April. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.  If their predictions are correct, in February wildfire activity could begin to pick up in parts of Texas, Oklahoma, Kansas, and New Mexico, with Florida and Georgia getting busier in March and April.

Below are the highlights of their report. Following that are outlooks for February through April, temperature and precipitation forecasts, and the Drought Monitor.

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“To begin 2017 significant wildland fire potential will be normal throughout entirety of the United States, except for below normal in Puerto Rico. For the majority of the U.S. this normal condition means that significant wildland fires are unlikely and normal indicates an out of fire season condition.

Beginning in February the seasonal increase in wildland fire activity will begin in the southern plains where the combination of abundant fine fuels and the potential for dry and windy conditions will occasional come together to produce periods of significant fire activity impacting the Southwest, Rocky Mountain and Southern Areas.

After February predictions for significant fire activity become increasingly difficult. It is likely that the same fire potential will continue across the southern plains, but pregreen up fires will also become increasingly likely in a large portion of the U.S. These fires are difficult to predict and rely on short term localized significant weather events.

Also during this period it is likely that we will see the onset of fire activity in south central Alaska, where warmer and drier than typical winter conditions are occurring.

Significant fire potential will also increase to above normal in Florida and portions of Georgia. Long term drought remains the primary concern in this area and moisture deficits in this area are likely to lead to occasional fires that burn deep into the soil layer and are more difficult to suppress.”

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Continue reading “Wildfire potential, January through April”

Beginning the 9th year of Wildfire Today

9th year Wildfire Today

Sunday the world marked the end of 2016, seen as a tough 12 months by some. But at Wildfire Today we are looking back with fond memories at the last 8 years as we begin our 9th. Our site was born January 6, 2008 with a rather modest post.

The success of the site would not have been possible without the loyal readers who come back on a regular basis, read the articles, leave insightful comments, and occasionally send us a message informing us of breaking news in the world of wildland fire.

So, a big Thank You to those who have visited or contributed in various ways over the last 8 years! We couldn’t have done it without you!