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QUANTIFYING CLIMATE CHANGE IMPACTS ON FOREST
AND RANGELAND VEGETATION, SPECIES SHIFTS, ECOSYSTEM PRODUCTIVITY
Research Description – The increasing concentration
of carbon dioxide in the earth’s atmosphere has raised concerns
about the potential changes in climate and climate variability resulting
from these changes in the earth’s atmosphere and the vulnerability
of ecosystems to these changes in climate. Forest and rangeland
vegetation, the geographic distribution of plant and animal species,
and the productivity of these ecosystems is strongly influenced
by the amount of rainfall and snow, the temperatures, the length
of the growing season and many other factors of the local climate.
Identifying the vulnerabilities of ecosystems and economies to climate
variability and change depends on an understanding of the sensitivity
of those systems to climate. This research uses computer models
to explore the impact of changes in climate on forest and rangeland
ecosystems.
Team Lead Scientist – Linda Joyce; ljoyce@fs.fed.us,
970-498-2560
Research Accomplishments and On-going –
Does spatial scale influence the estimation of climate change
impacts on forest productivity? The influence of spatial aggregation
on modeled forest responses to climate change was investigated by
applying the process-based Terrestrial Ecosystem Model (TEM) to
a fine resolution spatial grid (100 km2) and to a coarse resolution
spatial grid (2500 km2). Baseline (present) climate with ambient
CO2 and 2 future climates derived from the general circulation models
OSU and GFDL-Q with elevated atmospheric CO2. The aggregation error
of the national (U.S.) study area was very small, -0.4% (current
climate). The aggregation error for the OSU climate scenarios was
similar to the GFDL-Q climate scenario results and both results
were similar to the aggregation error of the baseline climate in
magnitude, sign, and spatial pattern. Forest-level aggregation error
ranged from -1.6 to 11.8%, with the largest aggregation error occurring
in boreal forest types. Aggregation errors were especially large
in transition regions between temperate and boreal forest types.
While aggregation error was similar across the baseline, GFDL-Q
and OSU scenarios, net primary productivity (NPP) response to the
climate changes in GFDL-Q and the OSU climates was an increase of
13 to 30% above the baseline NPP. Within each climate scenario,
the estimated NPP response to climate change differed by less than
1% between the coarse and fine resolutions. Except for transition
regions and regions with substantial variability in air temperature,
these simulations indicate that the use of 0.5° resolution provides
an acceptable level of aggregation error at the scale of a grid
cell, a forest biome, or the national level. Improvements could
be made by focusing computational intensity in heterogeneous regions
and avoid computational intensity in regions that are relatively
homogeneous with respect to vegetation and air temperature.
Publication: Nungesser, M.K.; Joyce, L.A.; McGuire, A.D. 1999. Effects
of spatial aggregation on predictions of forest climate change response.
Climate Research. 11: 109-124
POTENTIAL IMPACTS OF CLIMATE CHANGE ON THE SUPPLY AND DEMAND OF
TIMBER IN THE UNITED STATES AND GLOBALLY
Research Description – Effective public
policy and stewardship of natural resources includes consideration
of the projected costs and effects of different potential response
strategies to manage the risks of long-term climate change. The
ability to project potential future variation and changes in climate
and environmental conditions, subject to assumptions about natural
and human forcing, could enable resource managers to reduce damages
and seize opportunities to benefit from changing conditions by adapting
policy and management practices and activities. The Forest Service
Assessment process utilizes computer models to analyze the potential
effects of global climate change on the condition of renewable resources
on the forest and rangelands of the United States. This assessment
framework includes models that analyze the impact of climate change
and elevated carbon dioxide on ecosystem response, and the impact
on the supply and demand for timber in the forest sector. This framework
offers the opportunity to assess the effects of potential response
strategies on forest ecosystems and commodities, prices, incomes
and welfare in the forest sector. In addition, the costs of these
strategies both under potential climate change and without climate
change can be evaluated. This research will explore the potential
for management to address and when to address the risk and uncertainty
under long-term climate change.
Team Lead Scientist – Linda Joyce; ljoyce@fs.fed.us,
970-498-2560
Research Accomplishments and On-going –
Will climate change affect the forest sector in the United
States? The Forest Service conducts periodic assessments of
the condition of forest and rangeland resources under the authority
of the Renewable Resources Planning Act (RPA). These periodic assessments
synthesize and integrate the current state of scientific knowledge
for policy discussions. Increasing concentration of atmospheric
carbon dioxide has raised concerns about the vulnerability of forest
to the elevated carbon dioxide and potential changes in climate
and climate variability. The 1990 Food Protection Act, in amending
the 1974 RPA, requires the Forest Service to: 1) assess the impact
of climate change on the condition of renewable resources on forests
and rangelands, and 2) identify the rural and urban forestry opportunities
to mitigate the buildup of atmospheric carbon dioxide. Since the
Amendment, RPA assessments have included an analysis of the vulnerability
of U.S. forests to changes in climate. Joyce led these RPA climate
change assessments in 1989, 1995, and 2000. The 2000 RPA climate
change assessment (Joyce and Birdsey 2000) reviews our ability to
quantify the impacts of a changing climate on vegetation communities
and forest productivity, on the forest economy and land area changes,
on carbon stored and its associated uncertainties in forests, in
wood products, and in landfills and dumps. Current information on
opportunities for increasing carbon storage in forests is also synthesized.
Publications:
Joyce, L.A. 1997. Productivity of America's forests and climate
change. In: U.S. Department of Agriculture, Forest Service global
change research program highlights: 1991-1995. Gen. Tech. Rep. NE-237.
Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern
Forest Experiment Station: 97-102.
Joyce, L.A.; Birdsey, R.; Mills, J.; Heath, L. 1997. Progress toward
an integrated model of the effects of global change on United States
forests. In: U.S. Department of Agriculture, Forest Service Global
Change Research Program Highlights: 1991-1995. Gen. Tech. Rep. NE-237.
Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern
Forest Experiment Station: 93-96.
Joyce, L.A.; Birdsey, R., tech. eds. 2000. The impact of climate
change on America’s forests: a technical document supporting
the 2000 USDA Forest Service RPA Assessment. Gen. Tech. Rep. RMRS-GTR-59.
Fort Collins, CO: U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station. 133 p.
National Assessment Synthesis Team. 2000. Climate change impacts
on the United States. the potential consequences of climate variability
and change verview. Cambridge, U.K.: Cambridge University Press.
154 p.
Joyce, L.A.; Aber, J.; McNulty, S.; Dale, V.; Hansen, A.; Irland,
L.; Neilson, R.; and Skog, K. 2001b. Potential consequences of climate
variability and change for the forests of the United States. In:
National Assessment Synthesis Team. Climate change impacts on the
United States: the potential consequences of climate variability
and change. Cambridge, U.K.: Cambridge University Press: 489-522.
Parson, E.A.; Corell, R.W.; Barron, E.J.; Burkett, V.; Janetos,
A.; Joyce, L.A.; Karl, T.R.; MacCracken, M.C.; Melillo, J.; Granger,
M. Morgan; Schimel, D.S.; Wilbanks, T. 2003. Understanding climatic
impacts, vulnerabilities, and resilience in the United States: building
a capacity for assessment. Climatic Change. 57: 9-42.
Will climate change affect the global forest sector? Joyce
and others (1997) examined the impact of different future climate
scenarios on the global forest product trade. The four climate scenarios
produce consistent economic results, with expanding net primary
productivity of the world's forests generally hurting timber producers
and benefiting consumers. While regional changes in forest productivity
strongly influence the regional economic impact, the economic results
are also dependent upon whether the region is a producer or consumer
of timber. Projecting out 50 years implies some knowledge about
the forest sector infrastructure, particularly for countries such
as Russia and China that do not currently have a fully developed
forest sector. The uncertainty in the economic model appears to
be at least as great as the uncertainty as in the climate scenarios.
This study demonstrates the importance of examining the ecological
and the economic impacts of climate change on natural resources.
How do assumptions about the path and magnitude of future changes
in climate impact assessing the climate change impact on the global
forest sector? The productivity and trade responses in the
global forest sector may have implications for international efforts
to stabilize the atmospheric concentration of carbon dioxide. Joyce
in cooperation with Perez Garcia and McGuire, completed a study
that takes a step toward including the role of global forest sector
in integrated assessments of the global carbon cycle by linking
global models of climate dynamics, ecosystem processes and forest
economics to assess the potential responses of the global forest
sector to different levels of greenhouse gas emissions. The results
of this study indicate that assumptions within alternative climate
scenarios and about trade in forest products are important factors
that strongly influence the effects of climate change on the global
forest sector.
Publications:
Perez-Garcia, J.; Joyce, L.A.; Binkley, C.S.; McGuire, A.D. 1997.
Economic impacts of climatic change on the global forest sector:
an integrated ecological/economic assessment. Critical Reviews in
Environmental Science and Technology. 27(Special): S123-S138.
Perez-Garcia, J.; Joyce, L.A.; McGuire, A.D. 2002. Temporal uncertainties
of integrated ecological/economic assessments at the global and
regional scales. Forest Ecology and Management. 162: 105-115.
Perez-Garcia, J.; Joyce, L.A.; McGuire, A.D.; Xiao, X. 2002. Impacts
of climate change on the global forest sector. Climatic Change.
53: 439-461.
Will climate change influence natural disturbances such as
drought, insects, disease, or fire? Early studies on the effects
of climate change on forests focused on the ability of tree species
to tolerate temperature and moisture changes. Many scientists are
now recognizing – through modeling studies – the importance
of climate changes on disturbance regimes that determine the character
of forests. Trees can live for centuries, and have slowly evolved
to co-exist with natural disturbances such as fire, drought, insects,
diseases, and severe storm, but how will they be affected by a relatively
rapid change in climate? In their article Climate Change and Forest
Disturbances in the journal BioScience, a group of scientists with
wide-ranging backgrounds discuss how climate change may affect forests
by altering the frequency, intensity, duration, and timing of these
natural disturbances, plus the relatively new phenomenon of introduced
species. Some effects will be positive, some negative, and some
may cancel each other out. And effects will likely vary geographically.
A major problem, however, is uncertainty: we are entering uncharted
waters. Thus the authors suggest a variety of strategies for coping
with the possible effects of climate change:
Managing the system before the disturbance to reduce vulnerability
and enhance recovery.
Managing the disturbance itself to reduce impacts.
Managing recovery to speed processes and reduce future vulnerability.
Managing to determine the impacts of disturbances and effectiveness
of recovery efforts – the concept of adaptive management.
Publication:
Dale, V.H.; Joyce, L.A.; McNulty, S.; Neilson, R.P; Ayres, M.P.;
Flannigan, M.D.; Hanson, P.J.; Irland, L.C.; Lugo, A.E.; Peterson,
C.J.; Simberloff, D.; Swanson, F.J.; Stocks, B.J.; Wotton, B.M.
2001. Forest disturbances and climate change. Bioscience. 51: 723-734.
Quantifying the impact of climate change on US forests.
The objectives of this on-going research are to quantify the resource
management outcomes under no climate change and climate change in
the forest sector under a business as usual scenario and a scenario
with a future policy instrument focused on increasing carbon sequestration
above the baseline for US forests and forest products. Additionally
we hope to analyze the impacts and their timing at local and regional
scales in forest ecosystems and the forest sector, to identify potential
research issues involved in developing a more comprehensive approach
to risk assessment and management in the forest sector relative
to climatic change.
Participants –
Dr. Richard Haynes, John Mills, Pacific Northwest Research Station,
Portland, Oregon. This lab has maintained and developed the models
used to analyze the supply and demand of timber in the United States.
A recent publication on the use of the timber inventory model ATLAS
is available at http://www.fs.fed.us/pnw/pubs/gtr568.pdf. The recently
completed assessment of the timber sector is also available at http://www.fs.fed.us/pnw/pubs/gtr560/
Dr. John Perez-Garcia, Center for International Trade in Forest
Products, University of Washington. This lab maintains models used
to analyze the forest trade globally. http://www.cfr.washington.edu/People/Faculty/Perez-Garcia/index.html
Dr. Virginia Dale, Oak Ridge National Lab, Tennessee. Dr. Dale
lead the effort to look at the potential impacts of climate change
on natural disturbances. http://www.esd.ornl.gov/people/dale/dale.html
Dr. Ron Neilson, Pacific Northwest Research Station, Corvallis,
Oregon. This lab maintains and enhances ecological models that describe
the impact of climate on biogeography and ecosystem dynamics. http://www.fs.fed.us/pnw/corvallis/mdr/mapss/
CLIMATE CHANGE IMPACTS ON CARBON SEQUESTRATION
Research Description – Carbon sequestration
in forests is strongly influenced by land use changes and management
practices; yet until recently, ecological models examining the impact
of climate change have focused on potential vegetation without land
use. This omission is related to a lack of quantitative information
on historical land use, such as timber harvests. The objective of
this research was to develop a data set describing the area of forestland
harvested and remaining in forestland (not converted to other uses)
annually from 1700 at as fine a spatial resolution as possible and
yet have a nationally consistent data set of timber removed from
forestland on carbon sequestration patterns for U.S. forests.
Team Lead Scientist – Linda Joyce; ljoyce@fs.fed.us,
970-498-2560
Research Accomplishments and On-going – The research
has developed initial estimates of the harvest rates through time.
For the period from 1952 to 1997, Forest Service forest inventory
data on area and volume was intermittently available. Information
on acres harvested is limited and biased toward recent years--1970
to present. For the 1952 to 1997 period, we developed two approaches
(statistical and analytical) to estimate acres harvested from removal
and inventory volume data at the state level. To estimate harvest
information further back in time, we related the harvest disturbance
ratios to historical population levels and the initial recorded
settlement. These estimates will be compared to recently reconstructed
forestland use information at the national level. These data will
also be used to describe land use change impacts on carbon sequestration
from 1700 to 1997. Estimated harvest of wood will be compared to
a data set we developed of historical wood product production, including
fuel wood, from 1700 to 1999. Using conversion factors, this data
set allows us to estimate wood removals from forests over time.
Incorporating the trends in wood products through time is critical
as prior to 1930 over half of the wood removed was used as fire
or fuel wood. The methods we have developed provide a means of assessing
uncertainty contributed by historical patterns of land use and of
volume.
Participants – Dr. Dave McGuire, University
of Alaska/US Geological Survey. Dr. McGuire’s lab has developed
a new version of the Terrestrial Ecosystem Model that is capable
of considering the role of forest disturbance on carbon and nitrogen
fluxes of ecosystems, based on transient carbon dioxide concentrations
and transient climate variables. Additional information can be found
at Dr. Dave McGuire’s web site - http://picea.sel.uaf.edu/projects/usfspropres.html
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