United States Environmental Monitoring

Environmental Protection and Assessment Program

Agency Research Triangle Park, NC 27709

E AP Project Summary

Forest Health Monitoring 1992

Annual Statistical Summary

Research and Development EPA/620/SR-94/010 August 1994

In 1990, the United States Department of Agriculture (USDA), Forest Service (FS) and the United States Environmental Protection Agency (EPA), initiated a cooperative national program

to monitor the condition of the nation’s

forests. This multi-agency effort, within

the framework of the EPA’s Environmental Monitoring and Assessment Program (EMAP), is called the Forest Health

Monitoring (FHM) program. The FHM

program is jointly managed and largely

funded by the FS and EPA in cooperation with other program participants.

FHM partners provide additional financial and personnel support and include

participating State Forestry agencies,

United States Department of the Interior (USDI), Bureau of Land Management, the Tennessee Valley Authority

(TVA), and the USDA Soil Conservation

Service (SCS). Other Cooperators include universities, and three USDI agencies—U.S. Fish and Wildlife Service,

U.S. Geological Survey, and the National Park Service. The National Association of State Foresters provides essential program support, guidance, and

assistance.

Data analysis results for the following indicators are presented in the report: tree species and stand density

(mensuration), tree crown condition,

tree species diversity, and air pollution

bioindicator plants. The cumulative distribution function methods used in the

analysis provide a statistical summary

of most measurements. Tabular summaries were also prepared in some

cases. Where possible, indices have

been used in the CDF analysis.

This Project Summary was developed

by EPA’s Environmental Monitoring and

Assessment Program, Research 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

On FHM Detection Monitoring plots, a

set of indicators is used to classify forest

health status. These indicators collectively

represent many components of forest

health and are generally responsive to

many types of stresses. The indicators

are measured at various sites which are

selected statistically so that regional forest populations are represented.

The Project Report summarizes the data

that were collected as a result of the Detection Monitoring activities. Chapter two

of the report provides a brief overview of

forest health monitoring. The remaining

chapters summarize the data for tree species and stand density, tree crown condition, tree species diversity, and air pollution bioindicator plants. An overview of

indicator development, the plot network,

plot design, and data analysis procedures

are presented in several appendices.

Procedure

In 1992, Detection Monitoring activities

were conducted in twelve eastern states:

Alabama, Connecticut, Delaware, Georgia, Maine, Maryland, Massachusetts, New

Hampshire, New Jersey, Rhode Island,

Vermont, and Virginia (Figure 1). Detection Monitoring was also conducted in California and Colorado. Those data will be

S.A. Alexander
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included in the 1993 Annual Statistical

Summary as part of the western data

analysis.

The cumulative distribution function

(CDF) methods used in the analyses provide a statistical summary of most measurements. Tabular summaries were also

prepared in some cases. Where possible,

indices have been used in the CDF analysis.

Results and Recommendations

Mensuration

• Standard Federal Regions 1 and 2

combined have more dead trees (on

a per-area basis) than either Federal

Region 3 or Federal Region 4.

• This is apparently due to a noticeably

larger number of dead trees (per area)

across the major forest type groupings of spruce-fir forests and maple/

beech/birch forests.

• It would be premature to assume that

this reflects significantly increased

mortality and reduced regeneration in

these major forest type groupings

without additional information on

changes over time.

• Basal area per hectare shows roughly

the same distribution across all three

Standard Federal Regions.

Crown Assessments

• The defoliation of tree crowns was

examined through analysis of 3 ecological groups (species, forest types,

and crown groups) that were found

on 45 or more plots within any of the

four geographical regions (SFRs 1

and 2 combined, 3, 4, and 1-4 combined).

• The crown variables dieback and

transparency were aggregated into a

plot-level indicator that evaluated the

defoliation of the outer and inner portions of the tree crowns.

• Less than 10 percent of any population for any ecological group fell within

the subnominal category, and less

than 3 percent of any subnominal

population proportion was found in

the poor category.

• The only ecological groups that deserve a cursory investigation due to

the low proportions of populations in

a subnominal or poor condition are

one species (White ash) and two

crown groups (Cedar-Juniper; miscellaneous).

• No forest types had any significant

proportions of the population in the

subnominal or poor condition.

Species Diversity of Trees and

Saplings

• Species density was used as a measure of species diversity of trees and

saplings in Standard Federal Regions

1 and 2 combined, Federal Region 3,

and Federal Region 4. Two species

per unit area was used as a preliminary subnominal threshold.

• Standard Federal Region 4 had a significantly higher proportion of plots

with subnominal tree species density

than Federal Region 3. Federal Regions 1 and 2 combined and Federal

Region 3 did not differ significantly for

these proportions.

• Standard Federal Regions 1 and 2

combined had a significantly higher

proportion of plots with subnominal

sapling species density than either

Federal Region 3 or Federal Region

4.

Air pollution Bioindicator

Plants

• Field crews established biomonitoring

sites, for determining the presence or

absence of ozone injury conditions,

at 39 of the 212 forested plots in New

England.

• Based on data from 39 biomonitoring

sites, an estimated 27% ± 13% of the

forested population covered by these

sites showed foliar symptoms indicating the presence of ozone injury.

• Most of the plots rated positive for

ozone injury were located in rural areas that are known to be contaminated by air masses moving into the

region from urban-industrial areas to

the south of New England.

The information in this document has

been funded in part by the U.S. Environmental Protection Agency under Interagency Agreement number DW12935103-

01 with the USDA Forest Service and

Interagency Agreement number DW14935509-01 with the USDI Bureau of

Land Management. It has been subject to

the Agency’s peer and administrative review, and it has been approved for publication as an EPA document.

Mention of trade names or commercial

products does not constitute endorsement

or recommendation for use.

The report represents data from one

year of EMAP. Because the probabilitybased scientific design used by the EMAP

necessitates 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, temporal changes and trends

cannot be reported, as these require multiple years of observation. Please note

that this report contains data from demonstration studies in four Standard Federal

Regions. Appropriate precautions should

be exercised when using this information

for policy, regulatory or legislative purposes.

Figure 1. Sites in which detection monitoring occurred in 1982.
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Samuel A. Alexander (also the EPA Project Officer, see below) is with the

Environmental Monitoring and Assessment Program, Research Triangle Park,

NC 27709.

The complete report, entitled “Forest Health Monitoring–1992 Annual Statistical

Summary,” (Order No. PB94-205416/AS; Cost: $19.50; subject to change) will

be available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

Environmental Monitoring and Assessment Program–EMAP Center

U.S. Environmental Protection Agency

Research Triangle Park, NC 27709

• •

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

EPA/620/SR-94/010

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