Visualizzazione post con etichetta forest. Mostra tutti i post
Visualizzazione post con etichetta forest. Mostra tutti i post

domenica 27 luglio 2014

Trees save lives, reduce respiratory problems

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In the first broad-scale estimate of air pollution removal by trees nationwide, U.S. Forest Service scientists and collaborators calculated that trees are saving more than 850 human lives a year and preventing 670,000 incidents of acute respiratory symptoms.While trees’ pollution removal equated to an average air quality improvement of less than 1 percent, the impacts of that improvement are substantial. Researchers valued the human health effects of the reduced air pollution at nearly $7 billion every year in a study published recently in the journal Environmental Pollution.The study by Dave Nowak and Eric Greenfield of the U.S. Forest Service’s Northern Research Station and Satoshi Hirabayashi and Allison Bodine of the Davey Institute is unique in that it directly links the removal of air pollution with improved human health effects and associated health values. The scientists found that pollution removal is substantially higher in rural areas than urban areas, however the effects on human health are substantially greater in urban areas than rural areas.”With more than 80 percent of Americans living in urban area, this research underscores how truly essential urban forests are to people across the nation,” said Michael T. Rains, Director of the Forest Service’s Northern Research Station and the Forest Products Laboratory. “Information and tools developed by Forest Service research are contributing to communities valuing and managing the 138 million acres of trees and forests that grace the nation’s cities, towns and communities.”The study considered four pollutants for which the U.S. EPA has established air quality standards: nitrogen dioxide, ozone, sulfur dioxide, and particulate matter less than 2.5 microns (PM2.5) in aerodynamic diameter. Health effects related to air pollution include impacts on pulmonary, cardiac, vascular, and neurological systems. In the United States, approximately 130,000 PM2.5-related deaths and 4,700 ozone-related deaths in 2005 were attributed to air pollution.Trees’ benefits vary with tree cover across the nation. …


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#Alternative-Medicine, #Alzheimer, #Cancer, #Forest, #Forestservice, #Greater, #Health, #Institute, #Northernresearch, #Pollution, #Science, #Unitedstates

Fire ecology manipulation by California native cultures

http://feeds.feedburner.com/~r/sciencedaily/plants_animals/agriculture_and_food/~4/gx7F2x372s4

Before the colonial era, 100,000s of people lived on the land now called California, and many of their cultures manipulated fire to control the availability of plants they used for food, fuel, tools, and ritual. Contemporary tribes continue to use fire to maintain desired habitat and natural resources.Frank Lake, an ecologist with the U.S. Forest Service’s Pacific Southwest Station, will lead a field trip to the Stone Lake National Wildlife Refuge during the Ecological Society of America’s 99th Annual Meeting in Sacramento, Cal., this August. Visitors will learn about plant and animal species of cultural importance to local tribes. Don Hankins, a faculty associate at California State University at Chico and a member of the Miwok people, will co-lead the trip, which will end with a visit to California State Indian Museum.Lake will also host a special session on a “sense of place,” sponsored by the Traditional Ecological Knowledge section of the Ecological Society, that will bring representatives of local tribes into the Annual Meeting to share their cultural and professional experiences working on tribal natural resources issues.”The fascinating thing about the Sacramento Valley and the Miwok lands where we are taking the field trip is that it was a fire and flood system,” said Lake. “To maintain the blue and valley oak, you need an anthropogenic fire system.”Lake, raised among the Yurok and Karuk tribes in the Klamath River area of northernmost California, began his career with an interest in fisheries, but soon realized he would need to understand fire to restore salmon. Fire exerts a powerful effect on ecosystems, including the quality and quantity of water available in watersheds, in part by reducing the density of vegetation.”Those trees that have grown up since fire suppression are like straws sucking up the groundwater,” Lake said.The convergence of the Sacramento and San Joaquin rivers was historically one of the largest salmon bearing runs on the West Coast, Lake said, and the Miwok, Patwin and Yokut tribal peoples who lived in the area saw and understood how fire was involved.California native cultures burned patches of forest in deliberate sequence to diversify the resources available within their region. The first year after a fire brought sprouts for forage and basketry. In 3 to 5 years, shrubs produced a wealth of berries. Mature trees remained for the acorn harvest, but burning also made way for the next generation of trees, to ensure a consistent future crop. …


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#America, #Annual, #Coast, #Ecology, #Forest, #Health, #Indian, #Science, #State, #University, #Valley

venerdì 21 febbraio 2014

Forest model predicts canopy competition: Airborne lasers help researchers understand tree growth

http://feeds.feedburner.com/~r/sciencedaily/earth_climate/ecology/~4/slsmSqIImhs

Out of an effort to account for what seemed in airborne images to be unusually large tree growth in a Hawaiian forest, scientists at Brown University and the Carnegie Institution for Science have developed a new mathematical model that predicts how trees compete for space in the canopy.What their model revealed for this particular forest of hardy native Metrosideros polymorpha trees on the windward slope of Manua Kea, is that an incumbent tree limb greening up a given square meter would still dominate its position two years later a forbidding 97.9 percent of the time. The model described online in the journal Ecology Letters could help generate similar predictions for other forests, too.Why track forest growth using remote sensing, pixel by pixel? Some ecologists could use that information to learn how much one species is displacing another over a wide area or how quickly gaps in the canopy are filled in. Others could see how well a forest is growing overall. Tracking the height of a forest’s canopy reveals how tall the trees are and therefore how much carbon they are keeping out of the atmosphere — that is, as long as scientists know how to interpret the measurements of forest growth.James Kellner, assistant professor of ecology and evolutionary biology at Brown University, the paper’s lead and corresponding author, noticed what seemed like implausibly large canopy growth in LIDAR images collected by the Carnegie Airborne Observatory over 43 hectares on the windward flank of Manua Kea. In the vast majority of pixels (each representing about a square meter) the forest growth looked normal, but in some places the height change between 2007 and 2009 seemed impossible: sometimes 10 or 15 meters.The data were correct, he soon confirmed, but the jumps in height signaled something other than vertical growth. They signaled places where one tree had managed to overtop another or where the canopy was filling in a bare spot. The forest wasn’t storing that much more carbon; taller trees were growing a few meters to the side and creating exaggerated appearances of vertical growth in the overhead images.Turning that realization into a predictive mathematical model is not a simple matter. Working with co-author Gregory P. Asner at the Carnegie Institution for Science in Stanford, Calif., Kellner created the model, which provides a probabilistic accounting of whether the height change in a pixel is likely to be the normal growth of the incumbent tree, a takeover by a neighboring tree, or another branch of the incumbent tree.Tracking treetopsThe model doesn’t just work for this forest but potentially for different kinds of forests, Kellner said, because its interpretation of the data is guided by the data itself. …


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#Accounting, #Agriculture, #Cancer, #Carnegie, #Carnegieinstitution, #Forest, #Health, #King, #Pregnancy, #Professor, #Science, #University