United States
Environmental Protection
Agency
Atmospheric Research and
Exposure Assessment Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/620/SR-94/007 April 1994
&EPA Project Summary
Forest Health Monitoring 1991
Georgia Indicator Evaluation and
Field Study
S.A. Alexander, M. Baldwin, W.A. Bechtold, D.L. Cassell, S. Cline,
T. Droessler, J W. Hazard, J.G. Isebrands, V.J. LaBau, K.H. Riitters,
H. Schreuder, S.J. Steele, and M.S. Williams
The Forest Health Monitoring (FHM)
1991 Georgia Pilot study was under-
taken to conduct field research for ad-
vancing forest monitoring science
within the Environmental Monitoring
and Assessment Program (EMAP). In-
dicator developmental and operational
monitoring research was conducted si-
multaneously on plots. The pilot study
was designed to test methods for quan-
tifying vegetation structure, photosyn-
thetically active radiation (PAR),
dendrochronology, and selected root
fungi. The objective of the vegetation
structure study was to compare the
operational and informational charac-
teristics of area-based and point-based
methods for quantifying vertical and
horizontal vegetation structure and to
recommend a measurement system for
vegetation structure for 1992 and be-
yond. The primary objective of the PAR
study was to develop an efficient and
reliable method of using ceptometers
and quantum sensors for measuring
forest canopy light environments in
various stand conditions. The objec-
tives for dendrochronology were to de-
termine if the sampling intensity and
tree selection protocols were adequate
for quantifying diameter at breast height
(dbh) growth rates and trends on a
regional basis. The objectives for the
root disease study were to determine
the presence and severity of root dis-
ease using two root sampling methods
(the two-root method and the cubic foot
root collection method) and compare
the methods, and also to evaluate the
cubic foot method for quantifying
ectomycorrhizal fungi. The objective of
the tree height study was to determine
if the accuracy and precision of tree
height measuring devices were ad-
equate for providing a measure of tree
height change over time. The report
presents the results and recommenda-
tions based on those results.
This Project Summary was developed
by EPA's Atmospheric Research and
Exposure Assessment Laboratory, Re-
search Triangle Park, NC, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The Forest Health Monitoring (FHM)
1991 Georgia Pilot study was undertaken
to conduct field research for advancing
forest monitoring science within the Envi-
ronmental Monitoring and Assessment
Program (EMAP). Indicator developmen-
tal and operational monitoring research
was conducted simultaneously on plots.
The pilot study was designed to test
methods for quantifying vegetation struc-
ture, photosynthetically active radiation
(PAR), dendrochronology, and selected
root fungi. Testing the methods included
comparing different data collection proce-
dures for individual indicators, estimating
sampling efficiency (both of the sampling
design and the sampling unit design), and
evaluating spatial variability. In addition,
the accuracy and precision of tree height
instruments were determined. A brief over-
view of the study area is given in the
following section. More detailed informa-
Printed on Recycled Paper
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tion is presented in the Results and Rec-
ommendations section, which is organized
by indicator.
Procedure
The field work was conducted on a sys-
tematic grid consisting of 63 plots across
the state of Georgia. Figure 1 shows a
map of Georgia with county boundaries
and demo plot locations. Although there
were 63 potential plot locations, the land
use for many was something other than
forested (e.g., agricultural, urban, marsh).
Several of the indicator studies utilized
only 20 of the forested plots in western
Georgia. Figure 1 shows the pilot plot
locations.
Results and Recommendations
Vegetation Structure
The objective of the vegetation struc-
ture study was to compare the operational
and informational characteristics of area-
based and point-based methods for quan-
tifying vertical and horizontal vegetation
structure and to recommend a measure-
ment system for vegetation structure for
1992 and beyond.
The general superiority of the quadrat
method for sampling vascular plant spe-
cies richness at both plot and regional
levels was the most significant of several
methodological differences found between
the quadrat and pole methods. Compari-
sons of quadrat and pole diversity indices
and species accumulation curves sup-
ported this finding. This finding is impor-
tant because estimates of species richness
are the most basic and sensitive mea-
surements of the status of biotic diversity.
Although estimates of species richness
are basic and straightforward, they are
not simple. Field personnel must have a
working knowledge of the regional flora,
the ability to identify vascular plants under
field conditions based on experience or
using regional taxonomic keys, and the
ability to collect and press unknown plant
specimens for later identification.
In contrast, even though superior to the
pole method, the quadrat method imple-
mented in this study usually sampled only
70 to 80% (range 66 to 107%) of a crudely
estimated total plant species richness of
the plot and regional level. Therefore, sug-
gestions to reduce sample numbers per
plot must be thoroughly evaluated before
implementation, since the reliability of spe-
cies richness and other diversity calcula-
tions increases with sample size. The
quadrat method for measuring vegetation
structure was recommended for use in
future FHM field seasons based on these
findings.
Photosynthetically Active
Radiation (PAR)
The primary objective of the PAR study
was to develop an efficient and reliable
method of using ceptometers and quan-
tum sensors for measuring forest canopy
light environments in various stand condi-
tions. Several equipment problems were
worked out so that PAR data collection
can be considered reliable. The impor-
tance of measuring diffuse PAR in open
areas in addition to ambient PAR became
evident. Statistics indicated that 7 points
gave as good an estimate of PAR as 19
points, thereby reducing field work and
time.
Dendrochronology
The objectives for dendrochronology
were to determine if the sampling inten-
sity and tree selection protocols were ad-
equate for quantifying diameter at breast
height (dbh) growth rates and trends on a
regional basis. Based on the variance com-
ponent analysis, the sample intensity is
adequate. A graphical analysis of growth
patterns showed that cores, grouped by
species and age, showed similar patterns
of growth within groups. Specific species
should be sampled where possible
(loblolly pine, for example), to minimize
between-species variability in growth.
In addition, recommendations were
made for improving equipment, field sam-
pling, core handling, and preparation. The
recommendations should improve core
quality and expedite the measurement and
analysis process. A specific recommen-
dation was that cores should be prepared,
measured, and analyzed by one labora-
tory.
Root Disease
One objective was to determine the
presence and severity of root disease us-
ing two root sampling techniques: the two-
root method and the cubic foot root
collection method. The results showed that
the two-root method was more effective
than the cubic foot method in detecting
root disease pathogens.
Figure 1. Locations of the 1991 Georgia Pilot plots. The 20 plots used by several indicators are circled.
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Another objective was to evaluate the
cubic foot method for quantifying
ectomycorrhizal fungi. The field sampling
procedure was simple, but the laboratory
work was cumbersome and labor-inten-
sive. The core sample was considered
too large, and the variability between cores
was high. A smaller volume soil sample
and/or a soil subsampling procedure were
suggested to improve the procedure.
Tree Height
The objective was to determine if the
accuracy and precision of tree height mea-
suring devices were adequate for provid-
ing a measure of tree height change over
time. The authors concluded that a 10%
error in measuring tree height was com-
mon, especially for trees over 12 m in
height. A 10% measurement error is un-
acceptable for accurately estimating height
change over a 5-year period, therefore
tree height is not recommended as an
indicator at this time.
The research described in this report
has been funded by the U.S. Environmen-
tal Protection Agency. This document has
been prepared at the EPA Environmental
Research Laboratory in Corvallis, OR,
through Contract Nos. 68-C8-0006 to
ManTech Environmental Technology, Inc.,
68-CO-0049 to Lockheed Engineering and
Sciences Company, and 68-DO-0106 to
Statistical Consulting Service. It has been
subjected to the Agency's peer and ad-
ministrative review and approved for pub-
lication.
Mention of trade names or commercial
products does not constitute endorsement
or recommendation for use.
This report represents data from one year
of field operations of the Environmental
Monitoring and Assessment Program
(EMAP). Because the probability-based sci-
entific design used by the EMAP necessi-
tates multiple years of sampling, there is
uncertainty associated with these data. This
uncertainty will decrease as the full power
of the approach is realized. Similarly, tem-
poral changes and trends cannot be re-
ported, as these require multiple years of
observation. Please note that this report
contains data from demonstration studies
in one geographic region. Appropriate pre-
cautions should be exercised when using
this information for policy, regulatory, or
legislative purposes.
.S. GOVERNMENT PRINTING OFFICE: 19*4 - 5S4MH7/802W
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S.A. Alexander is with the U.S. EPA, EMAP Center, Research Triangle Park, NC
27711. M. Baldwin is with the Virginia Polytechnic and State University,
Blacksburg, VA 24061-0330. W.A. Bechtold is with the USDA Forest Service,
Southeast Experiment Station, Asheville, NC 28802. D.L Cassell is with the
Bureau of Land Management, Corvallis, OR 97333 (formerly of ManTech Envi-
ronmental Technologies, Corvallis, OR). S. Cline is with the Bureau of Land
Management, Las Vegas, NV 89193-3478 (formerly of ManTech Environmental
Technologies, Corvallis, OR). T. Dmessier is with ManTech Environmental
Technologies, Corvallis, OR 97333. J. W. Hazard is with the Statistical Consulting
Service, Bend, OR 97701. J.G. Isebrands and S.J. Steele are with the USDA
Forest Service Research Laboratory, Rhinelander, NC 54501. V.J. LaBauis with
the USDA Forest Service, Anchorage Forest Sciences Laboratory, Anchorage,
AK 99501. K.H. Riitters is with the Tennessee Valley Authority, Norris, TN 37828
(formerly of ManTech Environmental Technologies, Research Triangle Park,
NC). H. SchreuderandM.S. Williams are with the USDA Forest Service, Rocky
Mountain Station, Ft. Collins, CO 80526-2098.
Samuel A. Alexander is the EPA Project Officer (see below).
The complete report, entitled "Forest Health Monitoring 1991 Georgia Indicator
Evaluation and Field Study," (Order No. PB94-152394; Cost: $19,50; subject to
change) will be available only from
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at
Atmospheric Research and Exposure Assessment Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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