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62 records – page 1 of 7.

20th century climate warming and tree-limit rise in the southern Scandes of Sweden.

https://arctichealth.org/en/permalink/ahliterature95958
Source
Ambio. 2001 Mar;30(2):72-80
Publication Type
Article
Date
Mar-2001
Author
Kullman L.
Author Affiliation
Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden. leif.kullman@eg.umu.se
Source
Ambio. 2001 Mar;30(2):72-80
Date
Mar-2001
Language
English
Publication Type
Article
Keywords
Climate
Geography
Greenhouse Effect
Humans
Sweden
Trees - growth & development
Abstract
Climate warming by ca. 0.8 degree C between the late-19th and late-20th century, although with some fluctuations, has forced multispecies elevational tree-limit advance by > 100 m for the principal tree species in the Swedish part of the Scandinavian mountain range. Predominantly, these processes imply growth in height of old-established individuals and less frequently upslope migration of new individuals. After a slight retardation during some cooler decades after 1940, a new active phase of tree-limit advance has occurred with a series of exceptionally mild winters and some warm summers during the 1990s. The magnitude of total 20th century tree-limit rise varies with topoclimate and is mainly confined to wind-sheltered and snow-rich segments of the landscape. Thickening of birch tree stands in the "advance belt" has profoundly altered the general character of the subalpine/low alpine landscape and provides a positive feedback loop for further progressive change and resilience to short-term cooling episodes. All upslope tree-limit shifts and associated landscape transformations during the 20th century have occurred without appreciable time lags, which constitutes knowledge fundamental to the generation of realistic models concerning vegetation responses to potential future warming. The new and elevated pine tree-limit may be the highest during the past 4000 14C years. Thus, it is tentatively inferred that the 20th century climate is unusually warm in a late-Holocene perspective.
PubMed ID
11374309 View in PubMed
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Air quality in natural areas: interface between the public, science and regulation.

https://arctichealth.org/en/permalink/ahliterature162471
Source
Environ Pollut. 2007 Oct;149(3):256-67
Publication Type
Article
Date
Oct-2007
Author
K E Percy
D F Karnosky
Author Affiliation
Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, 1350 Regent Street, Fredericton, New Brunswick E3B 5P7, Canada. kpercy@nrcan.gc.ca
Source
Environ Pollut. 2007 Oct;149(3):256-67
Date
Oct-2007
Language
English
Publication Type
Article
Keywords
Air Pollutants - adverse effects - analysis
Air Pollution - adverse effects - analysis
Canada
Climate
Conservation of Natural Resources - legislation & jurisprudence - methods
Ecosystem
Environmental Monitoring - methods
Humans
Ozone - adverse effects - analysis
Recreation
Trees - growth & development
United States
United States Environmental Protection Agency
Abstract
Natural areas are important interfaces between air quality, the public, science and regulation. In the United States and Canada, national parks received over 315million visits during 2004. Many natural areas have been experiencing decreased visibility, increased ozone (O(3)) levels and elevated nitrogen deposition. Ozone is the most pervasive air pollutant in North American natural areas. There is an extensive scientific literature on O(3) exposure-tree response in chambered environments and, lately, free-air exposure systems. Yet, less is known about O(3) impacts on natural terrestrial ecosystems. To advance scientifically defensible O(3) risk assessment for natural forest areas, species-level measurement endpoints must be socially, economically and ecologically relevant. Exposure-based indices, based on appropriate final endpoints, present an underused opportunity to meet this need. Exposure-plant indices should have a high degree of statistical significance, have high goodness of fit, be biologically plausible and include confidence intervals to define uncertainty. They must be supported by exposure-response functions and be easy to use within an air quality regulation context. Ozone exposure-response indices developed within an ambient air context have great potential for improving risk assessment in natural forest areas and enhancing scientific literacy.
PubMed ID
17628236 View in PubMed
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An assessment of cumulative external doses from Chernobyl fallout for a forested area in Russia using the optically stimulated luminescence from quartz inclusions in bricks.

https://arctichealth.org/en/permalink/ahliterature158263
Source
J Environ Radioact. 2008 Jul;99(7):1154-64
Publication Type
Article
Date
Jul-2008
Author
V. Ramzaev
L. Bøtter-Jensen
K J Thomsen
K G Andersson
A S Murray
Author Affiliation
St Petersburg Institute of Radiation Hygiene, Mira Street 8, 197101 St Petersburg, Russia. v.ramzaev@mail.ru
Source
J Environ Radioact. 2008 Jul;99(7):1154-64
Date
Jul-2008
Language
English
Publication Type
Article
Keywords
Air pollution, radioactive - analysis
Chernobyl Nuclear Accident
Construction Materials
Ecosystem
Environmental Exposure - analysis
Humans
Quartz - analysis
Radiation Monitoring - methods
Russia
Trees - growth & development
Abstract
Optically stimulated luminescence (OSL) has been used for estimation of the accumulated doses in quartz inclusions obtained from two fired bricks, extracted in July 2004 from a building located in the forested surroundings of the recreational area Novie Bobovichi, the Bryansk Region, Russia. The area was significantly contaminated by Chernobyl fallout with initial (137)Cs ground deposition level of approximately 1.1 MBq m(-2). The accumulated OSL doses in sections of the bricks varied from 141 to 207 mGy, of which between 76 and 146 mGy are attributable to Chernobyl fallout. Using the OSL depth-dose profiles obtained from the exposed bricks and the results from a gamma-ray-survey of the area, the Chernobyl-related cumulative gamma-ray dose for a point detector located in free air at a height of 1m above the ground in the study area was estimated to be ca. 240 mGy for the time period starting on 27 April 1986 and ending on 31 July 2004. This result is in good agreement with the result of deterministic modelling of the cumulative gamma-ray dose in free air above undisturbed ground from the Chernobyl source in the Bryansk Region. Over the same time period, the external Chernobyl-related dose via forest pathway for the most exposed individuals (e.g., forest workers) is estimated to be approximately 39 mSv. Prognosis for the external exposure from 1986 to 2056 is presented and compared with the predictions given by other investigators of the region.
PubMed ID
18342414 View in PubMed
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The Arctic in an earth system context: from brake to accelerator of change.

https://arctichealth.org/en/permalink/ahliterature95707
Source
Ambio. 2006 Jun;35(4):153-9
Publication Type
Article
Date
Jun-2006
Author
Steffen Will
Author Affiliation
Centre for Resource and Environmental Studies, Australian National University, Canberra. steffen@cres.10.anu.edu.au
Source
Ambio. 2006 Jun;35(4):153-9
Date
Jun-2006
Language
English
Publication Type
Article
Keywords
Animals
Arctic Regions
Biodiversity
Carbon - metabolism
Cold Climate
Ecosystem
Environmental monitoring
Feedback, Biochemical
Greenhouse Effect
Humans
Ice
Plants - growth & development - metabolism
Transition Temperature
Trees - growth & development - metabolism
Abstract
Human activities over the past few centuries have profoundly changed the functioning of the earth system as a whole. These changes are particularly evident in the high latitudes of the Northern Hemisphere, where environmental change has been pronounced and rapid. Such changes have implications beyond the region, as they can lead to two important feedback processes: the ice-albedo feedback and the terrestrial carbon cycle-climate feedback. These processes play an exceptionally important role in earth system functioning, particularly because they may switch this century from damping the effects of anthropogenic climate change to accelerating them. Rapid environmental change in the high latitudes also has consequences for issues of direct importance to humans, particularly water resources.
PubMed ID
16944639 View in PubMed
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Source
Sci Am. 2010 May;302(5):66-73
Publication Type
Article
Date
May-2010
Author
Matthew Sturm
Author Affiliation
U.S. Army Corps of Engineers, USA.
Source
Sci Am. 2010 May;302(5):66-73
Date
May-2010
Language
English
Publication Type
Article
Keywords
Alaska
Arctic Regions
Fires
Global warming
Ice Cover
Photography
Plants - growth & development
Spacecraft
Trees - growth & development
World War II
PubMed ID
20443380 View in PubMed
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Arctic tree rings as recorders of variations in light availability.

https://arctichealth.org/en/permalink/ahliterature265262
Source
Nat Commun. 2014;5:3836
Publication Type
Article
Date
2014
Author
A R Stine
P. Huybers
Source
Nat Commun. 2014;5:3836
Date
2014
Language
English
Publication Type
Article
Keywords
Arctic Regions
Sunlight
Trees - growth & development
Volcanic Eruptions - adverse effects
Abstract
Annual growth ring variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the growth of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-ring characteristics. Here we show that Arctic tree-ring density is sensitive to changes in light availability across two distinct phenomena: explosive volcanic eruptions (P
Notes
Cites: Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):572-612518044
Cites: Nature. 2013 Apr 11;496(7444):201-523579678
Cites: Science. 2003 Jun 6;300(5625):1560-312791990
Cites: Science. 2003 Mar 28;299(5615):2035-812663919
PubMed ID
24805143 View in PubMed
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Bacterial and fungal community structure in Arctic tundra tussock and shrub soils.

https://arctichealth.org/en/permalink/ahliterature95659
Source
FEMS Microbiol Ecol. 2007 Feb;59(2):428-35
Publication Type
Article
Date
Feb-2007
Author
Wallenstein Matthew David
McMahon Shawna
Schimel Joshua
Author Affiliation
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA. wallenstein@lifesci.ucsb.edu
Source
FEMS Microbiol Ecol. 2007 Feb;59(2):428-35
Date
Feb-2007
Language
English
Publication Type
Article
Keywords
Arctic Regions
Bacteria - classification - growth & development
Cyperaceae - growth & development
DNA, Bacterial - analysis
DNA, Fungal - analysis
Ecosystem
Freezing
Fungi - classification - growth & development
Molecular Sequence Data
Proteobacteria - classification - growth & development
RNA, Ribosomal, 18S - genetics
Seasons
Sequence Analysis, DNA
Soil - analysis
Soil Microbiology
Trees - growth & development
Abstract
Fungal and bacterial community structure in tussock, intertussock and shrub organic and mineral soils at Toolik Lake, Alaska were evaluated. Community structure was examined by constructing clone libraries of partial 16S and 18S rRNA genes. The soil communities were sampled at the end of the growing season in August 2004 and just after the soils thawed in June 2005. The communities differed greatly between vegetation types, although tussock and intertussock soil communities were very similar at the phyla level. The communities were relatively stable between sample dates at the phyla and subphyla levels, but differed significantly at finer phylogenetic scales. Tussock and intertussock bacterial communities were dominated by Acidobacteria, while shrub soils were dominated by Proteobacteria. These results appear consistent with previous work demonstrating that shrub soils contain an active, bioavailable C fraction, while tussock soils are dominated by more recalcitrant substrates. Tussock fungi communities had higher proportions of Ascomycota than shrub soils, while Zygomycota were more abundant in shrub soils. Recent documentation of increasing shrub abundance in the Arctic suggests that soil microbial communities and their functioning are likely to be altered by climate change.
PubMed ID
17313585 View in PubMed
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Changes in forest productivity across Alaska consistent with biome shift.

https://arctichealth.org/en/permalink/ahliterature101844
Source
Ecol Lett. 2011 Apr;14(4):373-9
Publication Type
Article
Date
Apr-2011
Author
Pieter S A Beck
Glenn P Juday
Claire Alix
Valerie A Barber
Stephen E Winslow
Emily E Sousa
Patricia Heiser
James D Herriges
Scott J Goetz
Author Affiliation
Woods Hole Research Center, Falmouth, MA 02540, USA. pbeck@whrc.org
Source
Ecol Lett. 2011 Apr;14(4):373-9
Date
Apr-2011
Language
English
Publication Type
Article
Keywords
Alaska
Climate change
Droughts
Ecosystem
History, 20th Century
Picea - growth & development
Trees - growth & development
Abstract
Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline.
PubMed ID
21332901 View in PubMed
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Changes in vegetation cover and composition in the Swedish mountain region.

https://arctichealth.org/en/permalink/ahliterature278079
Source
Environ Monit Assess. 2016 Aug;188(8):452
Publication Type
Article
Date
Aug-2016
Author
Henrik Hedenås
Pernilla Christensen
Johan Svensson
Source
Environ Monit Assess. 2016 Aug;188(8):452
Date
Aug-2016
Language
English
Publication Type
Article
Keywords
Altitude
Betula - growth & development
Biodiversity
Climate change
Environmental Monitoring - methods
Forests
Sweden
Trees - growth & development
Abstract
Climate change, higher levels of natural resource demands, and changing land use will likely lead to changes in vegetation configuration in the mountain regions. The aim of this study was to determine if the vegetation cover and composition have changed in the Swedish region of the Scandinavian Mountain Range, based on data from the long-term landscape biodiversity monitoring program NILS (National Inventory of Landscapes in Sweden). Habitat type and vegetation cover were assessed in 1740 systematically distributed permanent field plots grouped into 145 sample units across the mountain range. Horvitz-Thompson estimations were used to estimate the present areal extension of the alpine and the mountain birch forest areas of the mountain range, the cover of trees, shrubs, and plants, and the composition of the bottom layer vegetation. We employed the data from two subsequent 5-year monitoring periods, 2003-2007 and 2008-2012, to determine if there have been any changes in these characteristics. We found that the extension of the alpine and the mountain birch forest areas has not changed between the inventory phases. However, the total tree canopy cover increased in the alpine area, the cover of graminoids and dwarf shrubs and the total cover of field vegetation increased in both the alpine area and the mountain birch forest, the bryophytes decreased in the alpine area, and the foliose lichens decreased in the mountain birch forest. The observed changes in vegetation cover and composition, as assessed by systematic data in a national and regional monitoring scheme, can validate the results of local studies, experimental studies, and models. Through benchmark assessments, monitoring data also contributes to governmental policies and land-management strategies as well as to directed cause and effect analyses.
PubMed ID
27387190 View in PubMed
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Climate change and the northern Russian treeline zone.

https://arctichealth.org/en/permalink/ahliterature95586
Source
Philos Trans R Soc Lond B Biol Sci. 2008 Jul 12;363(1501):2285-99
Publication Type
Article
Date
Jul-12-2008
Author
MacDonald G M
Kremenetski K V
Beilman D W
Author Affiliation
Department of Geography, University of California-Los Angeles, Los Angeles, CA 90095-1524, USA. macdonal@geog.ucla.edu
Source
Philos Trans R Soc Lond B Biol Sci. 2008 Jul 12;363(1501):2285-99
Date
Jul-12-2008
Language
English
Publication Type
Article
Keywords
Ecosystem
Geography
Greenhouse Effect
Population Dynamics
Russia
Species Specificity
Trees - growth & development
Abstract
The Russian treeline is a dynamic ecotone typified by steep gradients in summer temperature and regionally variable gradients in albedo and heat flux. The location of the treeline is largely controlled by summer temperatures and growing season length. Temperatures have responded strongly to twentieth-century global warming and will display a magnified response to future warming. Dendroecological studies indicate enhanced conifer recruitment during the twentieth century. However, conifers have not yet recolonized many areas where trees were present during the Medieval Warm period (ca AD 800-1,300) or the Holocene Thermal Maximum (HTM; ca 10,000-3,000 years ago). Reconstruction of tree distributions during the HTM suggests that the future position of the treeline due to global warming may approximate its former Holocene maximum position. An increased dominance of evergreen tree species in the northern Siberian forests may be an important difference between past and future conditions. Based on the slow rates of treeline expansion observed during the twentieth century, the presence of steep climatic gradients associated with the current Arctic coastline and the prevalence of organic soils, it is possible that rates of treeline expansion will be regionally variable and transient forest communities with species abundances different from today's may develop.
PubMed ID
18006415 View in PubMed
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62 records – page 1 of 7.