Post-fire environments are favourable for plant functioning of seeder and resprouter Mediterranean shrubs, even under drought
Authors: Antonio Parra, José M. Moreno
Understanding how drought affects seeder and resprouter plants during post-fire regeneration is important for the anticipation of Mediterranean vegetation vulnerability in a context of increasing drought and fire caused by climate change.
A Mediterranean shrubland was subjected to various drought treatments (including 45% rainfall reduction, 7 months drought yr−1), before and after experimental burning, by means of a rainout–shelter system with an irrigation facility. Predawn shoot water potential (Ψpd), relative growth rate (RGR), specific leaf area (SLA) and bulk leaf carbon isotopic composition (δ13C) were monitored in the main woody species during the first 3 yr after fire.
Cistus ladanifer seedlings showed higher Ψpd, RGR and SLA, and lower δ13C, than unburned plants during the first two post-fire years. Seedlings under drought maintained relatively high Ψpd, but suffered a decrease in Ψpd and RGR, and an increase in δ13C, relative to control treatments. Erica arborea, E. scoparia and Phillyrea angustifolia resprouts had higher Ψpd and RGR than unburned plants during the first post-fire year. Resprouters were largely unaffected by drought.
Overall, despite marked differences between the two functional groups, post-fire environments were favourable for plant functioning of both seeder and resprouter shrubs, even under the most severe drought conditions implemented.
Numerous fires create a smoky pall over the skies of western Africa. The image above was acquired on Dec. 10, 2015.
Credit: NASA Earth Observatory image by Joshua Stevens, using VIIRS data from Suomi NPP
NASA study finds a connection between wildfires, drought
January 10, 2017
NASA/Goddard Space Flight Center
For centuries drought has come and gone across northern sub-Saharan Africa. In recent years, water shortages have been most severe in the Sahel — a band of semi-arid land situated just south of the Sahara Desert and stretching coast-to-coast across the continent, from Senegal and Mauritania in the west to Sudan and Eritrea in the east.
Various factors influence these African droughts, both natural and human-caused. A periodic temperature shift in the Atlantic Ocean, known as the Atlantic Multi-decadal Oscillation, plays a role, as does overgrazing, which reduces vegetative cover, and therefore the ability of the soil to retain moisture. By replacing vegetative cover’s moist soil, which contributes water vapor to the atmosphere to help generate rainfall, with bare, shiny desert soil that merely reflects sunlight directly back into space, the capacity for rainfall is diminished.
Another human-caused culprit is biomass burning, as herders burn land to stimulate grass growth, and farmers burn the landscape to convert terrain into farming land and to get rid of unwanted biomass after the harvest season. As with overgrazing, fires dry out the soil and stymie the convection that brings rainfall. Small particles called aerosols that are released into the air by smoke may also reduce the likelihood of rainfall. This can happen because water vapor in the atmosphere condenses on certain types and sizes of aerosols called cloud condensation nuclei to form clouds; when enough water vapor accumulates, rain droplets are formed. But have too many aerosols and the water vapor is spread out more diffusely to the point where rain droplets don’t materialize.
Tree-bark thickness indicates fire-resistance in a hotter future
January 11, 2017
A new study has found that trees worldwide develop thicker bark when they live in fire-prone areas. The findings 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. 9 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.
A severe fire, left to burn instead of suppressed, cleared an area of forest in the Illilouette Creek Basin in Yosemite National Park, allowing it to become a wetland. Wetlands and meadows provide natural firebreaks that make the area less prone to catastrophic fires.
Credit: Scott Stephens, UC Berkeley
Wildfire management vs. fire suppression benefits forest and watershed
Long-term experiment in Yosemite shows managing fires can help make forest more resilient to fire
October 24, 2016
University of California – Berkeley
An unprecedented 40-year experiment in a 40,000-acre valley of Yosemite National Park strongly supports the idea that managing fire, rather than suppressing it, makes wilderness areas more resilient to fire, with the added benefit of increased water availability and resistance to drought.
Wildfires did not emerge until 80 million years after plants first evolved. Researchers say there was simply not enough oxygen in the Earth’s ancient atmosphere to support burning at this time. (Photo : Flickr: NPS Climate Change Response)
Ancient Wildfires: Researchers Examine Evolution Of Forest Fires
Even though plants first emerged on Earth 400 million years ago, it was not until approximately 80 million years later that wildfires began ripping through forests and grasslands like they do today in California, a new study revealed.
So, if there was plenty of foliage, what prevented raging wildfires during this time? Researchers from University of Royal Holloway London discovered that there simply was not enough oxygen in the atmosphere, according to a news release. It turns out that widespread forest fires were not present until around 360 million years ago, in the latest Devonian Period, when oxygen levels rose to above 17 percent. Today, the atmospheric oxygen is approximately 21 percent, the release noted.
My name is Todd Smith and I am the Managing Director at Jarrimber, a timber furniture manufacturer based in Australia. Working with timber every-day, I take a keen interest in developments in the forestry industry.
With the recent outbreak of forest fires in Canada, and the series of bushfires that took place in Australia earlier this year, I thought it might be interesting to create some content on the topic. Below is a link to a story-map that I have created, detailing some of the worst forest fires in recent times.
I have also pasted the embed code below for the story-map.
Reducing catastrophic wildfires through managed burns
Source: Northern Arizona University
A new article suggests catastrophic wildfire danger could be reduced by increasing use of planning burning in land management plans.
This year’s wildfire season in the United States is one of the worst on record in terms of damage and costs. Reducing the risk of future destructive wildfires could be achieved by more prescribed burns and managed lightning-caused fires, according to a paper released this week in the journalScience.
Authors of the paper, Reform Forest Fire Management, including Northern Arizona University School of Forestry Professor Pete Fulé, intended to raise awareness among stakeholders of the critical role of fire in forest management and to promote the use of fire on a larger scale.
“This paper’s theme is about management and is essentially encouraging the use of fire at times and places when it can be used to reduce fuels, to thin forests and restore the ecological role of fire and to help reduce the occurrence of very severe fires in forests where those fires were not characteristic in the past,” Fulé said.
Prescribed burns are planned fires to reduce the accumulation of fuels on the forest floor. Managed fires are usually caused by lightning and are allowed to burn, similar to the way fires burned naturally before fire suppression.
In areas of ongoing fire suppression, fuels have accumulated to dangerous levels, enhancing the likelihood of dangerous and devastating fires. While the paper, an opinion piece, advocates for the increased use of fire in forest management, Fulé said agencies in Arizona are already successfully using fire to reduce wildfire risk.
But the paper’s authors think a lot more should be done to protect forests and ecosystems, especially as development continues to expand into formerly undisturbed settings. Fulé said another concern is funding for proactive restoration efforts is regularly transferred to wildfire suppression efforts.
The southwest is moving northward, pushed there by California wildfires, as researchers from University of California, Davis recently reported in the Journal of Ecology.
That is, as fires burn forest understories, the plants that grow in their place are increasingly those normally found in more southern parts of the West. “The plants we’re finding underneath our forests are becoming more like those seen in Mexico and Southern California,” said lead author Jens Stevens, a postdoctoral scholar with UC Davis, in a release. “Under climate change, we’re seeing species from drier, warmer areas increasingly taking over. It’s a long process, but forest disturbance, be it thinning or wildfire, has the potential to hasten those shifts.”
This can be a startling change: A forest floor normally strewn with lupine and violets, typical of Northern California and Canada–may now be manzanita and monkey flower, or other foliage normally found to the south, a release noted.
Scattered Jeffrey pine tree mortality, foreground, on Laguna Mountain in the Cleveland National Forest, with a recent fire scar in the background. Gray trees are dormant black oak or possibly dead oak.
Drought kills 12 million trees in California’s national forests
At least 12 million trees have died in California’s forest due to drought
Four years of drought have had a severe effect on California’s forests
Millions of trees continue to die in California due to drought and bark beetle invasion
Rangers in the San Bernardino National Forest call them “red trees.”
Instead of the typical deep green color, large swaths of pine trees now don hues of death, their dehydrated needles turning brown and burnt-red because of the state’s worsening drought.
“Unlike back East, where you have fall colors, here it’s because the trees are dying,” said John Miller, a spokesman for the San Bernardino National Forest.
Years of extremely dry conditions are taking a heavy toll on forest lands across California and heightening the fire risk as summer approaches.
“The situation is incendiary,” William Patzert, a climatologist for the Jet Propulsion Laboratory, told The Times recently. “The national forest is stressed out.”
A new study by the U.S. Forest Service tried to assess the scope of the problem. Researchers estimated that the drought has killed off at least 12.5 million trees in California’s national forests during the drought.
The scientists expect the die-off to continue. “It is almost certain that millions more trees will die over the course of the upcoming summer as the drought situation continues and becomes ever more long term,” said biologist Jeffrey Moore, acting regional aerial survey program manager for the U.S. Forest Service.
ULUGURU Mountain ranges provide perhaps one of the best sceneries that Tanzania is endowed with and the beauty of the near Morogoro Municipality proves the splendor the nation can be proud of.
Apart from historical caves found in the mountain ranges that the natives used as hiding locations during war, the settings also cater for water sources for consumers in Morogoro Town and beyond.
However, destructive human activities undertaken in close proximity to the water sources on the slopes of the Uluguru Mountains threaten sustainability of the supply at the same time undermining efforts by the government to meet its objectives on improvement of water services.
During interview with ‘the Daily News’ in Morogoro recently, the Managing Director of Morogoro Urban Water Supply and Sanitation Authority (MORUWASA) Eng Nicholaus Angumbwike named wild-fires, agricultural activities, house construction and animal husbandry as major activities posing serious threat to the ‘survival’ of water sources.
Drought, fire management and land use changes have led to denser forests in California
by Bob Yirka
In analyzing the data, the researchers found that large tree density is lower in the more recent years than early last century, for all parts of the state, with some declines as high as 50 percent. In their place are small tree and brush growth, which they found has a much higher density than a hundred years ago. They also noted that over the same period, California has grown drier, as many studies have confirmed. It is the increased water stress, the team suggests, that is at least partly responsible for the change in tree densities. Another factor is fire management. In the past, before people arrived, fires, generally due to lightening strikes would start, and burn thousands of acres before dying natural deaths. That would allow for new growth, which would eventually lead to tall tree growth. Now, whenever a fire starts, it is put out as quickly as possible to protect homes and businesses in the area. The result is highly dense forests with dry small trees—the perfect conditions for fires to start and spread very quickly. The researchers also found that oak trees have grown more numerous while pine populations have declined—another result of the drier climate.
The study suggests that California forest managers are likely to be facing some tough decisions in the years ahead as the planet heats up and the state becomes drier.
Wildfires May Contribute More to Global Warming Than Previously Predicted
Wildfires produce a witch’s brew of carbon-containing particles, as anyone downwind of a forest fire can attest. A range of fine carbonaceous particles rising high into the air significantly degrade air quality, damaging human and wildlife health, and interacting with sunlight to affect climate. But measurements taken during the 2011 Las Conchas fire near Los Alamos National Laboratory show that the actual carbon-containing particles emitted by fires are very different than those used in current computer models, providing the potential for inaccuracy in current climate-modeling results.
“We’ve found that substances resembling tar balls dominate, and even the soot is coated by organics that focus sunlight,” said senior laboratory scientist Manvendra Dubey, “Both components can potentially increase climate warming by increased light absorption.”