Aspen/FACE - CO2 & Ozone Interaction
The Aspen FACE (Free-Air Carbon Dioxide Enrichment) Experiment is a multidisciplinary
study to assess the effects of increasing tropospheric ozone and carbon dioxide levels on
aspen forest ecosystems.
Research Partners
FACE Investigators
Funding Partners
George Host and Judd Isebrands are the major contributing modellers to the Aspen/FACE
project and details of the Ecophys model can be found at its home page.
http://www.nrri.umn.edu/nrri/ecophys.html
George Host and Judd Isebrands are the major
contributing modellers to the Aspen/FACE project and details of the Ecophys model can be
found at its home page.
http://www.nrri.umn.edu/nrri/ecophys.html
Global Change (IGBP)
The International Geosphere-Biosphere Programme (IGBP) is an
interdisciplinary scientific activity established and sponsored by the International
Council of Scientific Unions (ICSU). The Programme was instituted by ICSU in 1986,
and the IGBP Secretariat was established at the Royal Swedish Academy of Sciences in 1987.
http://www.igbp.kva.se/index.html
Free-Air Carbon Dioxide Enrichment (FACE) Experiment
Wheat crop on 11 May 1993 showing phenological differentiation. The different water
treatments are separated by a small partly hidden walkway (leadiong from the middle of the
left edge to the right upper corner of the figure). The DRY half plot (with 50% of the
full water supply) is located in the left upper portion of the figure. The half plot
visible in the foreground got fully water supply to meet evapotranspiration [WET]. The
accelerating effects on phenology and senescence due to the drought (between the top and
the bottom) and the CO2 enrichment (AMBIENT outside the ring, enriched CO2 [FACE] inside
the ring) including their combined effects are clearly visible.
http://www.pik-potsdam.de/act/face/e/fig2b.htm
FIRST FINDING FROM FOREST GROWING IN 21st-CENTURY ATMOSPHERE
Trees Increase Their Rate of Photosynthesis Upton, NY - Scientists at the U.S.
Department of Energy's Brookhaven National Laboratory and at Duke University report that
loblolly pine trees grown in a 21st century atmosphere of increased carbon dioxide (CO2)
show a marked increase in their rate of photosynthesis.
In a season-long experiment, the researchers found that the rate of photosynthesis in
pines growing in elevated CO2 was 65 percent higher than in pines growing in the present
CO2 environment. They also found that the trees' water consumption did not change in
response to the elevated CO2, unlike the decrease typically seen in crops and herbaceous
plants.
David Ellsworth, tree physiologist with Brookhaven Lab, said, "Ours is the only
study of this sort that has ever been conducted in a forest, yet one-third of Earth's land
mass is covered by forests. Up to now, we have not been able to study how an entire forest
would respond to increased CO2."
Principal researchers in the study also include tree physiologist Ram Oren, of Duke
University, and ecologist George Hendrey, also of Brookhaven. Their work is reported in a
paper soon to be published in the journal Oecologia. Ellsworth is scheduled to present the
findings on August 1, at the annual meeting of the Ecological Society of America in
Snowbird, Utah.
About FACE The forest experiment was the first use of FACE technology in a forest
environment. FACE, which stands for free-air carbon-dioxide enrichment, was developed by
Dr. Hendrey and colleagues at Brookhaven to study effects of enhanced CO2 on plants in
their natural environment. Only such experiments, conducted in open air rather than in
greenhouses or any other types of enclosures, can mimic "real world" conditions
in order to simulate how entire ecosystems will cope with the predicted higher-CO2
atmosphere of the next century.
Levels of CO2 in the atmosphere have risen from 280 parts per million (ppm) at the
beginning of the Industrial Revolution in the late 18th century to 355 ppm today, an
increase of over 25 percent, primarily because of increased fossil-fuel combustion.
Scientists expect that the current level will double some time in the next century.
Dr. Hendrey and colleagues have previously used FACE to evaluate effects of increased
CO2 on agricultural crops in Mississippi and Arizona, and on grassland in Switzerland.
In the FACE system, an array of vertical pipes encircling the test area releases CO2 in
a computer-controlled mixture with ambient air. The computer measures wind direction, wind
speed and the CO2 concentration in the center of the array, and uses this information to
adjust the rate of gas to be released on a second-to-second basis. The resulting
environment is as close as practical to the atmosphere expected to prevail in the middle
of the 21st century.
In the Duke Forest The forest experiment was carried out on mature loblolly pine trees
in North Carolina, in a forest owned by Duke. Used for timber, loblolly pines are the
mainstay of the lumber industry in the Southeast. While increased photosynthesis may
result in faster-growing trees and, hence, more wood, the researchers caution against
viewing their results as entirely good news. It is not yet clear that the extra
photosynthesis will be reflected in faster growth. Said Dr. Ellsworth, "These are
early findings, and there are many questions still unanswered. What about competition from
other trees? Will the forest outstrip the soil's capacity to support enhanced growth?
Would faster-growing wood be more brittle? It's not so simple."
The Experiment Ahead Already begun is a much broader, multi-year experiment. Besides
continuing the tree physiology work, this next experiment will include soil and
atmospheric studies. Dozens of ecologists and plant biologists will work at the Duke
forest site, collecting data not only on loblolly pines, but also on sweetgums, dogwoods,
honeysuckle, junipers, and microbes and soils. Results from the study will be used in
global computer models to predict the role of vegetation in future CO2 exchange with the
atmosphere.
The FACE approach gives many scientists access to a large facility that encompasses
hundreds of individual plants in an intact ecosystem. This reduces the cost per scientist
dramatically. The net effect is an economical way to build an understanding of how a
particular ecosystem will respond to rising levels of CO2.
FACE research is supported by the Department of Energy's Office of Health and
Environmental Research, Ecological Research Division. Brookhaven National Laboratory
carries out basic and applied research in the physical, biomedical and environmental
sciences and in selected energy technologies. Brookhaven is operated by Associated
Universities, Inc., a nonprofit research management organization, under contract to the
Department of Energy.
http://www.pubaf.bnl.gov/pr/bnlpr073095.html
Free-Air Co2 Enrichment Project (FACE)
"The Free-Air CO2 Enrichment (FACE) Project: Determination
of the effects of elevated CO2 and interacting environmental variables on
agronomic crops.
Numerous CO2-enrichment studies in greenhouses and growth
chambers have suggested that growth of most plants should increase about 30% on the
average with a projected doubling of the atmospheric CO2 concentration.
However, the applicability of such work to the growth of plants outdoors under less ideal
conditions has been seriously questioned. The only approach that can produce an
environment as representative of future fields as possible today is the free-air CO2-enrichment
(FACE) approach"
http://www.uswcl.ars.ag.gov/epd/co2/co2face.htm
Free-Air Carbon Dioxide Enrichment (FACE) Experiment
The concentration of CO2 in the earth's atmosphere has increased continuously since the
beginning of the industrial period, and will probably have doubled by the end of the 21st
Century (Keeling and Whorf 1991, Schimel et al. 1995). Within the framework of a FACE
experiment conducted by the U.S. Water Conservation Laboratory (USWCL), Phoenix, Arizona,
in the Sonoran Desert, concentrations of CO2 as they may be expected within the coming 50
to 75 years were established and maintained for the first time under open-air conditions,
and their impact on agricultural cultivated plants (cotton, wheat and barley) was
investigated. For this purpose, the concentration of CO2 within the air is raised for the
FACE plots in the experimental field to 550 ppm (FACE) as against 370 ppm (Control), under
otherwise undisturbed atmospheric conditions (Lewin et al. 1993). Results achieved in
previous experiments under laboratory conditions or in chambers concerning the effects of
raised concentrations of CO2 are not representative of actual open-air conditions due to
technically-conditioned disturbances of the atmospheric energy, water and CO2 exchange and
the microclimatic and biological changes resulting therefrom. In the FACE experiment, the
distinct effects for ambient and enriched atmospheric CO2 and for two steps of water
supply (sufficient [WET], 50% [DRY]) were investigated in the runs for 1992-94. In the
runs for 1995-97 similar studies will be realised with varying supplies of nitrogen.
http://www.pik-potsdam.de/act/face/e/face_1.htm
Brookhaven National Laboratory U.S. Department of Energy
http://www.face.bnl.gov/
National and International Sorghum News
http://www.ars-grin.gov/ars/SoAtlantic/Mayaguez/sorghum.html
