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Tag Archive: forests

  1. Researchers find post-fire logging harms spotted owls

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    • Post-fire logging damages important spotted owl foraging areas in “snag forest habitat” that is created by patches of intense fire. This habitat is rich in the small mammal prey species that the owls feed upon, but post-fire logging largely removes this habitat, thereby causing higher rates of territory abandonment
    January 17, 2018 by John Muir Project read full article at phys.org

    Wildlife ecologists studying the rare spotted owl in the forests of California have discovered that large, intense wildfires are not responsible for abandonment of breeding territories. Instead, the researchers found that post-fire logging operations, which are common on both private and National Forest lands, most likely caused declines in territory occupancy of this imperiled wildlife species.

    In the absence of post-fire logging, they found no significant effect of large forest fires on spotted owl territory occupancy. Post-fire logging damages important spotted owl foraging areas in “snag forest habitat” that is created by patches of intense fire. This habitat is rich in the small mammal prey species that the owls feed upon, but post-fire logging largely removes this habitat, thereby causing higher rates of territory abandonment.

    “This is good news for declining California because this is something that we can control—we can make policy decisions to stop post-fire logging operations in spotted owl habitat….

    …The scientists’ findings also expand upon previous research that found very high spotted owl occupancy after the 257,000-acre Rim fire of 2013 in the Sierra Nevada prior to post-fire logging. The current study found a decline in owl territory occupancy in the same area after post-fire logging occurred. A co-author on both studies, Dr. Derek Lee, also of Wild Nature Institute, said, “It is time to stop thinking logging will help the forest; we need to take a much more hands-off approach to forest management so natural processes can re-establish.”

  2. Managing forests for cooler microclimates

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    • Forest density has a large impact on the microclimatic landscape near the ground.
    • Forest management has the potential to slow down biodiversity loss by reducing forest fragmentation and creating buffer zones around cold places so they remain cold, when close-by forest is cut down.

    January 11, 2018 Stockholm University Read full ScienceDaily article here

    When studying the effect of climate change on biodiversity, it is important to consider the climate near the ground (microclimate) which a plant or an animal actually experiences. Deep shady depressions, dense old forests or places close to water for example are always considerably cooler than their surroundings.

    “Knowing where cold climate refugia are in the landscape means we can protect these cold spots and help cold-adapted species to survive a warmer climate. Knowing how colder microclimates are generated means we could even create colder spots by wisely managing our forests,” says Caroline Greiser, PhD student at Department of Ecology, Environment and Plant Sciences.

    The scientists found out that summer maximum temperatures at the forest floor can differ more than 10°C over only 100 meters.

    “We also found out that the forest plays a dominant role in controlling warm near-ground temperatures in the summer, more than local topography. In other words, the temperature differences between open and dense forest stands are larger than the differences between the sunny and the shady side of a hill” says Caroline Greiser….

    …Microclimate is the climate near the ground which can be colder or warmer than in the free atmosphere, depending on local topography (e.g. north vs. south side of a hill, higher vs. lower elevation) and vegetation (e.g. young sparse vs. old dense forest).

    Caroline Greiser, Eric Meineri, Miska Luoto, Johan Ehrlén, Kristoffer Hylander. Monthly microclimate models in a managed boreal forest landscape. Agricultural and Forest Meteorology, 2018; 250-251: 147 DOI: 10.1016/j.agrformet.2017.12.252

  3. In California’s wildfires, a looming threat to climate goals

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    • CA’s environmental regulations apply only to human-caused emissions. Carbon and other pollution generated by wildfires is outside state law.
    • Forests are part of the state’s strategy for cutting greenhouse-gas emissions significantly by 2020 and beyond…. The air board will direct state agencies to determine more precisely how much carbon can be absorbed by California’s variety of landscapes….
    • The U.S. Forest Service this week updated its estimate of dead trees across California to 129 million. That loss alone could be a blow to the state’s vision of a low-carbon future.

    by Julie Cart December 14 2017 Read full CalMatters article here

    Beyond the devastation and personal tragedy of the fires that have ravaged California in recent months,  another disaster looms: an alarming uptick in unhealthy air and the sudden release of the carbon dioxide that drives climate change.

    …..The state’s environmental regulations are known to be stringent, but they have limits: They apply only to human-caused emissions. Carbon and other pollution generated by wildfires is outside the grasp of state law.

    ….In less than one week, for example, October’s wine-country fires discharged harmful emissions equal to that of every car, truck and big rig on the state’s roads in a year. The calculations from the subsequent fires in Southern California are not yet available, but given the duration and scope of the multiple blazes, the more recent complex of fires could well exceed that level.

    The greenhouse gases released when forests burn not only do immediate harm, discharging carbon dioxide and other planet-warming gases, but also continue to inflict damage long after the fires are put out. In a state where emissions from nearly every industry are tightly regulated, if wildfires were treated like other carbon emitters, Mother Nature would be castigated, fined and shut down.

    The air board estimates that between 2001 and 2010, wildfires generated approximately 120 million tons of carbon. But Clegern said a direct comparison with regulated emissions is difficult, in part because of limited monitoring data….

    ….Scientists estimate that in severely burned areas, only a fraction of a scorched tree’s emissions are released during the fire, perhaps as little as 15 percent. The bulk of greenhouse gases are released over months and years as the plant dies and decomposes.  And if a burned-out forest is replaced by chaparral or brush, that landscape loses more than 90 percent of its capacity to take in and retain carbon, according to the [Sierra Nevada] Conservancy….

    ….The role of wildfire as a major source of pollution was identified a decade ago, when a study conducted by the National Center for Atmospheric Research concluded that “a severe fire season lasting only one or two months can release as much carbon as the annual emissions from the entire transportation or energy sector of an individual state.”

    ….The entire equation has been made worse by the state’s epidemic of tree death, caused by drought, disease and insect infestation. The U.S. Forest Service this week updated its estimate of dead trees across California to 129 million. That loss alone could be a blow to the state’s vision of a low-carbon future.

    ….Forests as carbon-chewers are part of the state’s strategy for cutting greenhouse-gas emissions significantly by 2020 and beyond—a goal that could be undermined by nature’s caprice. The air board will direct state agencies to determine more precisely how much carbon can be absorbed by California’s variety of landscapes….

    ….Sean Raffuse, an analyst at the Air Quality Research Center at the University of California, Davis, came up with the “back of the envelope” calculations for October’s Sonoma County fires.

    Raffuse said he used federal emissions inventories from fires and calculated that five days of ashy spew from the northern California blazes equated to the annual air pollution from every vehicle in California….

     

  4. Forest resilience declines in face of wildfires in a warmer climate

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    • They found significant decreases in tree regeneration following wildfires in the early 21st century, a period markedly hotter and drier than the late 20th century. The research team said that with a warming climate, forests are less resilient after wildfires.
    • While trees similar to the ones that burned have typically been planted on a fire-ravaged site, that may no longer be the smartest approach. Managers may want to plant species that are adapted to the current and future climate, not the climate of the past.

    December 12, 2017 Colorado State University read full ScienceDaily article here

    The forests you see today are not what you will see in the future. That’s the overarching finding from a new study on the resilience of Rocky Mountain forests.

    ….They wanted to understand if and how changing climate over the last several decades affected post-fire tree regeneration, a key indicator of forest resilience.

    They found sobering results, including significant decreases in tree regeneration following wildfires in the early 21st century, a period markedly hotter and drier than the late 20th century. The research team said that with a warming climate, forests are less resilient after wildfires.

    ….Stevens-Rumann said that while trees similar to the ones that burned have typically been planted on a fire-ravaged site, that may no longer be the smartest approach….

    Managers may want to plant species that are adapted to the current and future climate, not the climate of the past,” she said. “There also are areas that could support certain tree species but there isn’t any regeneration currently; these are the ideal places to plant after a fire.”

    The problem could also be addressed when a fire happens.

    Another strategy is to foster fires burning under less extreme conditions, so that more trees survive to provide seed for future forests,” said Penny Morgan, professor at the University of Idaho and co-author of the study. “When fires are patchy, more areas are within reach of a surviving tree.”…

    Camille S. Stevens-Rumann, Kerry B. Kemp, Philip E. Higuera, Brian J. Harvey, Monica T. Rother, Daniel C. Donato, Penelope Morgan, Thomas T. Veblen. Evidence for declining forest resilience to wildfires under climate change. Ecology Letters, 2017; DOI: 10.1111/ele.12889

  5. Mapping biodiversity of forests with remote sensing; the more diverse, the more resilient

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    Posted: 13 Nov 2017 06:55 AM PST  read full ScienceDaily article here

    Productivity and stability of forest ecosystems strongly depend on the functional diversity of plant communities. Researchers have developed a new method to measure and map functional diversity of forests at different scales — from individual trees to whole communities — using remote sensing by aircraft [paving] the way for future airborne and satellite missions to monitor global plant functional diversity.

    Ecological studies have demonstrated positive relationships between plant diversity and ecosystem functioning. Forests with higher functional diversity are generally more productive and stable over long timescales than less diverse forests. Diverse plant communities ….can better cope with changing environmental conditions — an insurance effect of biodiversity. They are also less vulnerable to diseases, insect attacks, fire and storms.

    Researchers from the UZH and the California Institute of Technology / NASA Jet Propulsion Laboratory have now developed a new remote-sensing method to map functional diversity of forests from small to large scales, independent of any predefined vegetation units or species information and without the need for ground-based calibration….

    With airborne laser scanning, the scientists measured morphological characteristics of the forest canopy such as canopy height, foliage and branch densities. These measurements indicate how the sunlight is taken up by the canopy to assimilate carbon dioxide from the air and use the carbon to grow. In a canopy with a more diverse structure, light can better spread between different vertical canopy layers and among individual tree crowns, allowing for a more efficient capture of light. The researchers also characterized the forest with regards to its biochemical properties using airborne imaging spectroscopy. By measuring how leaves reflect the light in many spectral bands, they were able to derive physiological traits such as the content of leaf pigments (chlorophylls, carotenoids) and leaf water content

    We can see, for example, if a tree is suffering water stress, and what resource allocation strategy a tree is following or how it adapts to the environment,”

    Fabian D. Schneider et al. Mapping functional diversity from remotely sensed morphological and physiological forest traits. Nature Communications, 2017; 8 (1) DOI: 10.1038/s41467-017-01530-3


  6. Carbon feedback from forest soils accelerates global warming

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    • Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores
    • Humans release about 10 billion metric tons (Gt) of carbon into the atmosphere each year and Earth’s soils contain about 3500 billion metric tons (Gt) of carbon which if added to atmosphere could accelerate global warming
    • Over the course of the 26-year experiment (which still continues), the warmed plots lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters of soil
    • Study demonstrates value of long term data sets

    October 5, 2017  Marine Biological Laboratory  read full ScienceDaily article here

    After 26 years, the world’s longest-running experiment to discover how warming temperatures affect forest soils has revealed a surprising, cyclical response: Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores. The study indicates that in a warming world, a self-reinforcing and perhaps uncontrollable carbon feedback will occur between forest soils and the climate system, accelerating global warming.

    ….each year, mostly from fossil fuel burning, we are releasing about 10 billion metric tons of carbon into the atmosphere. That’s what’s causing the increase in atmospheric carbon dioxide concentration and global warming. The world’s soils contain about 3,500 billion metric tons of carbon. If a significant amount of that soil carbon is added to the atmosphere, due to microbial activity in warmer soils, that will accelerate the global warming process. And once this self-reinforcing feedback begins, there is no easy way to turn it off. There is no switch to flip.”…

    ….”if the microbes in all landscapes respond to warming in the same way as we’ve observed in mid-latitude forest soils, this self-reinforcing feedback phenomenon will go on for a while and we are not going to be able to turn those microbes off. Of special concern is the big pool of easily decomposed carbon that is frozen in Arctic soils. As those [Arctic] soils thaw out, this feedback phenomenon would be an important component of the climate system, with climate change feeding itself in a warming world….”

    Heated and control plots in a long-term soil warming study at Harvard Forest, Petersham, Mass. Jerry Melillo of the Marine Biological Laboratory, Woods Hole, Mass., and colleagues began the study in 1991.
    Credit: Audrey Barker-Plotkin
    …Melillo and colleagues began this pioneering experiment in 1991 in a deciduous forest stand at the Harvard Forest in Massachusetts. They buried electrical cables in a set of plots and heated the soil 5° C above the ambient temperature of control plots. Over the course of the 26-year experiment (which still continues), the warmed plots lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters of soil….
    J. M. Melillo, S. D. Frey, K. M. DeAngelis, W. J. Werner, M. J. Bernard, F. P. Bowles, G. Pold, M. A. Knorr, A. S. Grandy. Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world. Science, 2017; 358 (6359): 101 DOI: 10.1126/science.aan2874
  7. Finally, a focus on saving the great forests of the Sierra. But is it too late? SacBee Editorial

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    • “There is an urgent need to reform policy and management to ensure that Californians continue to benefit from these forests for generations to come,” a new Public Policy Institute of California report says
    • Reducing forest density could have the side benefit of increasing run-off by as much as 9 percent, filling streams and rivers for the good of fisheries and for residential, agriculture and industrial use, the PPIC report says.

    Sacramento Bee Editorial  September 21, 2017 read full SacBee editorial here

    We Californians take for granted the great forests of the Sierra Nevada. It is where we ski and hike, and breathe fresh air, and it’s the primary source of our water.

    It’s all at risk. Drought and bark beetle infestation are the proximate cause of death of more than 100 million trees in California since 2010. But the forests were weakened by climate change, combined with mismanagement that includes well-intentioned wildfire prevention efforts and logging in past decades of old-growth trees, which are most resistant to fire and disease.

    [Governor] Brown and the Legislature approved another $225 million in cap-and-trade revenue, reserved for the fight against climate change, for forests. That underscored one of California’s inconvenient truths. Like refineries, diesel engines and cars powered by internal combustion, burning and decaying forests spew greenhouse gases.

    In April, the Governor’s Tree Mortality Task Force reported that the 2013 Rim Fire at Yosemite emitted 12.06 million tons of carbon dioxide, three times more than all the greenhouse gas reductions achieved that year in all other sectors in California. Worse, the detritus decomposing in the burn area will unleash four times that amount of greenhouse gas in coming decades.

    In much of the 15 million acres of mountains from Kern to Siskiyou counties, forests are choking with 400 sickly trees per acre, four times the number in healthy forests. Tools to heal the forests are at hand, but forest management is fraught.

    …Some environmentalists oppose logging, while some conservative politicians advocate unraveling environmental restrictions to allow for far more logging. Neither extreme is helpful. Flexibility is needed. The Clean Air Act could, for example, allow for the use of prescribed fires.

    …Reducing forest density could have the side benefit of increasing run-off by as much as 9 percent, filling streams and rivers for the good of fisheries and for residential, agriculture and industrial use, the PPIC report says.

    The report says the cost of wise forest management might not be astronomical. In time, it might pay for itself, assuming mills are retooled or built to accommodate smaller and mid-size timber. Such mills could provide jobs in parts of the state where unemployment is chronically high.

    …Our re-engineered state of 40 million people faces many problems. The water delivery system is oversubscribed and antiquated. Billions of dollars should be spent to reinforce California against floods.

    But there is cause for optimism. Laird last month announced the Tahoe-Central Sierra Initiative with other top officials, and some significant environmental groups are joining longtime advocates to focus on Sierra restoration. There is some support in Congress for wiser forest management.

    And now comes an infusion of state money, not to be taken for granted, and none too soon.

  8. Maximizing successful forest restoration in tropical dry forests

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    • tests maximizing success of tree replanting efforts in degraded soils in tropics
    • tree species that were drought tolerant did better
    • soil amendments only helped to get seedlings off to good start

    September 21, 2017 University of Minnesota read full ScienceDaily article here

    A new study has uncovered some valuable information on ways to maximize the success of replanting efforts [in tropical dry forests], bringing new hope for restoring these threatened ecosystems.

    …Over the past century most of these forests, which help keep water clean and provide valuable habitat for wildlife, were replaced by farms and cattle pastures. Now, as conservationists work to replant deforested areas, they’re finding that the already challenging, high-clay soils underlying them have been degraded to an extent that makes it hard for tree seedlings to sink their roots.

    …To find out what works best for reestablishing tropical dry forests, the researchers planted seedlings of 32 native tree species in degraded soil or degraded soil amended with sand, rice hulls, rice hull ash or hydrogel (an artificial water-holding material). After two years, they found that tree species known for traits that make them drought tolerant, such as enhanced ability to use water and capture sunlight, survived better than other species. Some of the soil amendments helped get seedlings off to a good start, but by the end of the experiment there was no difference in survival with respect to soil condition

    Leland K. Werden, Pedro Alvarado J., Sebastian Zarges, Erick Calderón M., Erik M. Schilling, Milena Gutiérrez L., Jennifer S. Powers. Using soil amendments and plant functional traits to select native tropical dry forest species for the restoration of degraded Vertisols. Journal of Applied Ecology, 2017; DOI: 10.1111/1365-2664.12998

  9. ‘Keep it local’ approach more effective than government schemes at protecting rainforest

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    September 12, 2017 University of Cambridge  read full ScienceDaily article here

    Conservation initiatives led by local and indigenous groups can be just as effective as schemes led by government, according to new research. In some cases in the Amazon rainforest, grassroots initiatives can be even more effective at protecting this vital ecosystem

    …”Policy makers must focus on a more diverse set of mechanisms for protecting the rapidly disappearing tropical forests,” said Schleicher. “Our analysis shows that local stewardship of the forest can be very effective at curtailing forest degradation and conversion in the Peruvian Amazon. Local conservation initiatives deserve more political, financial and legal support than they currently receive.”

    “Our analysis shows that there is no single way of protecting tropical forests, and multiple approaches are required to stem the relentless tide of forest conversion and degradation,” said co-author Professor Carlos Peres from UEA’s School of Environmental Sciences.

    Judith Schleicher, Carlos A. Peres, Tatsuya Amano, William Llactayo, Nigel Leader-Williams. Conservation performance of different conservation governance regimes in the Peruvian Amazon. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-10736-w

  10. Warming may quickly drive forest-eating beetles north, says study

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    • Pines in Canada and much of US at risk

    August 28, 2017 Lamont-Doherty Earth Observatory, Columbia University  read full ScienceDaily article here

    Over the next few decades, global warming-related rises in winter temperatures could significantly extend the range of the southern pine beetle — one of the world’s most aggressive tree-killing insects — through much of the northern United States and southern Canada, says a new study. The beetle’s range is sharply limited by annual extreme temperature lows, but these lows are rising much faster than average temperatures — a trend that will probably drive the beetles’ spread, say the authors. The study was published today in the journal Nature Climate Change.

    …Until recently, southern pine beetles lived from Central America up into the southeastern United States, but in the past decade or so they have also begun appearing in parts of the Northeast and New England…

    …”We could see loss of biodiversity and iconic regional forests. There would be damage to tourism and forestry industries in already struggling rural areas.” Coauthor Radley Horton, a researcher at Columbia University’s Lamont-Doherty Earth Observatory, said infested forests could also dry out and burn, endangering property and emitting large amounts of carbon into the atmosphere

    Corey Lesk, Ethan Coffel, Anthony W. D’Amato, Kevin Dodds, Radley Horton. Threats to North American forests from southern pine beetle with warming winters. Nature Climate Change, 2017; DOI: 10.1038/nclimate3375