Center for Forest Environmental Studies

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United States Department of Agriculture Joie Rs

Forest Service, Southern Region
Rt 1, Box 182 A
Dry Branch, GA 31020

Forestry Report R8-FR 13

hat changes do we face in environmental

\ \ conditions and what are their effects on our

forests’ growth and vigor? Efforts to measure the impact

of these conditions will be major goals of a new Forest
Service facility.

rees’ health and growth varies with a forest’s
T changing environment. For example, trees willreact
to high levels of ozone, acid rain, ultraviolet light, and
carbon dioxide. Other environmental factors are also
thought to be changing at this time. It is vitally important
to understand how forests are affected by these environ-
mental factors.

o address this complex subject, the Center for

Forest Environmental Studies has been built at Ma-
con, GA. The Center is a state-of-the-art facility equipped
to produce information needed to evaluate and respond to
changing environmental stresses, particularly air pollu-
tion.

The Greenhouses and Headhouse

he 7,000-square-foot greenhouse is designed to

closely control as many environmental factors as
possible. All air continuously passes through a series of
filters to remove particles and chemical pollutants. An air
conditioner maintains specified temperatures. The un-
usual glass in the roof transmits more light than does
conventional glass, particularly in the infrared spectrum.

The glass softens shadows, and helps prevent burning of
2

the foliage below. A large backup generator starts auto-
matically in the event of an electrical failure.

he 2,000-square-foot headhouse contains
T equipment to support studies being conducted in
the greenhouse. This includes a pot-filling machine, a
water purification system and a complex system of com-
puters and monitors that control the exposure equipment.
The Center also uses additional laboratory and office
space in the nearby Southern Forest Fire Laboratory.

The Exposure Equipment

he Center has two major types of equipment: 12
T rain tables that expose plants to simulated rainfall
and 20 continuously stirred tank reactors (CSTR's) that
expose plants to gaseous pollutants.

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ach raintable includes about 180 needles set in an
3 eight-armed hub. Simulated rain falls from the
needles, which are supplied with water by a pulsating
pump. This system applies extremely uniform drops,
which fall on a round, rotating table on which seedlings
are placed. A variety of equipment in the headhouse puri-
fies tap water. Then chemicals are added to simulate those
found in rain. A series of tanks at the pumping-and-
mixing station allows several different solutions of simu-
lated rain to be tested at the same time.

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Rain tables.

4

he CSTR’s are chambers in which seedlings are
: placed and exposed to controlled levels of gaseous
pollutants. They are being used to test the effects of ozone
at this time, but can be easily adapted to test the effects of
a wide variety of other gases, including carbon dioxide
and sulfur dioxide. The CSTR’s at this facility are among
the most sophisticated in the world because their computer
controls allow for variable concentrations of gases.

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Continuously stirred tank reactors (CSTR's)

Current and Future Projects

hree projects are underway to evaluate the effects of

acid rain on forests and forest resources. The first
study will compare the growth and physiology of loblolly
pines exposed to three levels of rain acidity. In addition,
this test will compare the responses of five typical south-
ern forest soils to various levels of rain acidity. This study
will last two years and will make daily use of the rain
tables. The second study will evaluate the effects of simu-
lated acid rain on the most destructive disease of southern
pines. It will compare the effects of three levels of rain
acidity on the ability of fusiform rust to attack various
seedlots of loblolly pine.The third study will look at the
effects of simulated acid rain on dogwood anthracnose,
another fungus disease that is rapidly spreading in the
East. It will evaluate the ability of the anthracnose fungus
to attack dogwood seedlings grown under four different
levels of rain acidity. Additional projects to evaluate the
effects of acid rain are being planned.

everal studies are planned for the CSTR's. The
S objective of one study will be to develop a screen-
ing method to identify seedlots from commercially im-
portant trees that can tolerate ozone. If foresters could
identify air pollution resistant trees and plant them now,
they may be able to minimize the impact of this stress in
the future. A second study will evaluate the interactions
between ozone and fusiform rust or other disease agents.

A nother study will evaluate the sensitivity of other
plants present in the ecosystem. This information
6

would help managers of wilderness areas determine con-
centrations of air pollutants that affect sensitive species. It
may also help identify plants that could serve as an early
warning of the presence of pollutants.

he effects of fluctuations in ozone concentrations

over time are important, but have been difficult to
study with manually controlled exposure systems. The
computer controls on these CSTR's should make them
ideal for future studies of this type.

he Center is large enough and its equipment

versatile enough to conduct several evaluations at
the same time. Only minimal alteration of the facilities
would be required to examine the effects of changes in
carbon dioxide, temperature, ultraviolet light, and other
environmental factors. The interactions between different
factors such as ozone and acidrain can also be studied. The
Center will be able to provide information needed to
maintain healthy and productive forests in our constantly
changing environment.

The Center for Forest Environmental Studies was
built by the USDA Forest Service with funds from the
Southern Commercial Forest Research Cooperative
of the National Acid Precipitation Assessment Pro-
gram. The Center operates through the cooperative
efforts of the Forest Service’s Southern Region,
Southeastern Forest Experiment Station, and the
Georgia Forestry Commission.

Persons of any race, color, national origin, sex,
age, religion, or with any handicapping condition are
welcome to use and enjoy all facilities, programs, and
services of the USDA. Discrimination in any form is
strictly against agency policy, and should be reported
to the Secretary of Agriculture, Washington, DC
20250.