This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
Aerial Sketch Mapping Surveys the Past,
Present and Future 1
Timothy J. McConnell 2
Abstract-Aerial sketch mapping has been used as a detection and
monitoring tool, over large geographical areas, for over fIfty years.
Mexico, Canada and the United States share a common need, sketch
mapper expertise. Aerial survey data is only as good as the sketch
mapper. The leadership ofthe Forest Health Monitoring Program
in the United States for standardization and support of aerial
sketch mappers can serve as a model for improving the quality and
quantity for aerial surveys in all three countries.
Since the advent of forest land management, specialists
have looked for methods to document changes in forest
ecosystem health over large areas. Aerial sketch map surveys have become the most efficient and cost effective method
of detecting visible forest change events over a large geographical area since the 1950's.
Definitions
An aerial sketch map survey consists of using an aircraft
with a trained observer to systematically fly over a forested
area to detect visible changes in the forest, such as mortality,
defoliation and blowdown. Once detected, while in the air,
the affected area is drawn on a map, then attributed with
the appropriate information. Upon landing, a draft map
product is already completed. For this paper, the words
"sketch mapper", "observer", "sketch map observer" and
"aerial observer" are synonymous and "aerial sketch map
survey", "aerial survey" and "survey" are also synonymous.
There are two primary types of aerial surveys: the overview or general survey and the specific or detailed operational survey. The overview aerial survey is more of a
landscape level assessment capturing a multitude of forest
change events. A high wing airplane is generally used, along
with a map with a scale of 1;250,000 to 1: 100,000. An
example of this type of survey would be the annual aerial
surveys conducted once a year in the western United States.
A specific or operational aerial survey covers a smaller
geographical area and focuses on one to a few special events.
A specific aerial survey may be conducted either by airplane
or helicopter, alongwithamap scaleof1:100,000 to 1:24,000.
An example would be the aerial surveys in southeastern
United States to sketch map areas with recent mortality by
southern pine beetle. Southern pine beetle may be conducted four to seven times a year, depending on the number
of bark beetle generations a year.
Ipaper presented at the North American Science Symposium: Toward a
Unified Framework for Inventorying and Monitoring Forest Ecosystem
Resources, Guadalajara, Mexico, November 1-6,1998.
2Timothy J. McConnell is the Aerial Survey Program Manager, USDA
Forest Service, Northern Region, Forest Health Protection, P.O. Box 7669,
200 East Broadway, Missoula, MT 59807. Tel: (406) 329-3136; Fax: (406)
329-3132; e-mail: tmcconneIVrl@fs.fed.us
USDA Forest Service Proceedings RMRS-P-12. 1999
Words of Caution--Just as in any other form of forest
ecosystem inventorying and monitoring, the use of proper
techniques and qualified personnel are very important to
the success of that method. Conducting an aerial survey
from an aircraft is difficult and challenging work. It must
be planned, conducted and completed by well qualified
aerial observers.
Past complaints about aerial survey data usually stem
from the lack of experience, training or attitude of the aerial
sketch ma p observer. "Since forest pests and the damage they
cause are dynamic and highly variable, the resulting data
will also be highly variable. No two sketchmappers will or
can be expected to record the same outbreak in exactly the
same way. For this reason sketchmapping should be regarded more as an art than as an exact science ....
Sketchmapping is highly subjective, and the resulting data
can be no more accurate than the competence of the
sketch mapper and the conditions under which the data was
obtained." (Klein, 1983.)
An aerial sketch map survey requires not only qualified,
motivated sketch mappers, but a great deal of mission
planning to insure that the data collected is valuable, the
survey is cost-effective and that above all, it is completed in
a safe manner.
Forest change event signatures must be visible from the
air. Extreme wind throw or abundant bark beetle caused
mortality are easily seen from the air, while light adelgid
infestations or very light defoliation from larval feeding on
foliage is likely to not be visible. Therefore, the signature and
visible thresholds for various damaging agents must be
understood and taken into account in the planning process.
Other complaints can be found related to the fact that the
users of the data did not understand the scope, scale or
intent of the aerial survey that produced the data.
Qualifications for a Sketch Mapper
Observer
The cost of sending one or two observers up in an aircraft
gets more expensive every year. Valuable forest health
moni toring money can be wasted easily by sending less than
qualified sketch mappers up in to the air. When using
aircraft in natural resource management, an aviation
management program is a must, and is frequently forgotten
in fledgling aerial survey programs. Qualified sketch mapping aerial observers must be able to:
1. Read maps proficiently so they can track the aircraft
position, navigate the aircraft and locate the affected
area on the ground and on the map. (If you don't know
where you are, you can't draw a polygon on the map
accurately. )
59
2. Have good eye sight and normal color perception.
3. Identify forest disturbance agent signatures, which
usually come in the form of foliage color change or tree
crown or canopy texture change.
4, Draw or sketch the affected area on to a map (of
appropriate scale) the way it appears (shape) on the
forest below. A small affected area on the ground may
be only a point on the map, where a large affected area
will be delineated with a polygon. (Good sketch mappers don't draw large area circles because they don't
accurately represent most affected areas.)
5. Mter the affected area has been marked or delineated
on the map, it must be attributed with the causal agent,
host and a relative intensity or tree count of damage.
Other valuable qualities of a good sketch mapper include:
• Having a working knowledge of forest insect and diseases, and their hosts indigenous to the survey area.
• Having a sincere interest in flying a sketch map mission.
• Being able to control motion sickness.
• Having the ability and experience to plan an aerial
survey mission.
• Having on the ground field experience in the survey
area.
• Having knowledge of meteorology and weather, especially in the survey area.
• Having the ability to be a team player.
• Depending on the aptitude of the observer, 50 to 200
hours of training time in an aircraft.
Other Important Aerial Survey Variables-Besides
the observers, there are many other variables that can
contribute to the quality of information collected. A sketch
mapper must be familiar with the conditions and methods
that affect the quality of the survey. These include:
• Timing the survey to observe the forest change event
at its optimum visible signature. This may mean
waiting for the damaged foliage to turn red or flying
the area before the damaged foliage has been washed
away by rain or wind.
• Timing the survey to have the best light. High sun angle
is very important, so best light is at noon in the summer
months in North America. Cumulus clouds can create
dark shadows causing a monochromatic view that is
less than acceptable, where an even, high cirrus cloud
cover can be beneficial.
• Fly the survey at the appropriate altitude above ground
level to be able to detect the signatures of interest.
• Fly the survey at a speed that is slow enough to allow the
sketch mapper to locate and identify the signature, draw
the area as it appears in the forest canopy onto the map
and attribute the point or polygon, yet fast enough to be
safe and cost-effective.
• Turbulent air can make an observer anxious and uncomfortable and be the cause of reduced concentration to do
the work.
There are many other variables that can affect the quality
of an aerial survey. Some of them include; the type of
aircraft, the attitude and ability of the pilot, other air traffic,
radio communication, terrain, and smoke haze. Even with
all these variables, aerial survey data has value in tracking
60
trends, providing quick response information, providing
annual information over large areas and can serve as the
first phases of a multi-stage sampling scheme.
ThePast ____________________
A Little History
In 1919, Gordon Hewitt recommended. using aircraft for
forest insect detection after flying mosquito breeding areas
in parts of British Columbia. In 1920, an open cockpit
hydroplane was used to survey a spruce budworm infestation in parts of Quebec and Ontario. Another early attempt
to survey forest insect damage from the air was made by
J.M. Miller, over the Sierra National Forest, in California, in
1925, in an open cockpit airplane. In 1930, the Bureau of
Entomology used a Forest Service airplane to survey bark
beetle outbreak areas of Yellowstone National Park. In
1931, F.P. Keen, from the Portland Forest Insect Laboratory
and C.S. Cowan, Chief Fire Warden of the Washington State
Fire Association conducted the first recorded aerial survey
of a forest insect outbreak in the two northwest states, when
they delineated a hemlock looper outbreak in southwest
Washington. In 1947, the annual aerial survey program was
instituted by the Bureau of Entomology and Plant Quarantine, US Department of Agriculture and cooperators from
the States ofWashington and Oregon and the Weyerhaeuser
Timber Company.
The pioneers of the modern aerial survey, when it began
in Portland, Oregon, were: W.J. Buckhorn, a seasoned entomologist and John F. Wear, a young research forester and
pilot, just out of graduate school after World War II.
The More Recent Past
Other aerial survey attempts and program developments
occurred in the fifties and sixties in the United States. Early
attempts to develop programs share much of the same
challenges as today's program efforts, such as; (1) qualified
observers, (2) budgets than can cover costs for aircraft, (3)
suitable map bases for sketch mapping, and (4) suitable
aircraft and qualified pilots. Within the USDA Forest Service, most Forest Health Protection groups and conduct
aerial surveys. Ten years ago, some of these groups had no
aerial survey program or so small a program that only an
occasional event was flown. Some expected satellite technology of the 1970's to replace the "old fashioned" aerial survey.
Without the interest and expertise, some regional programs
lost their ability to conduct aerial surveys. In recent years
the National Forest Health Monitoring Program (FHM) in
the United States, has provided leadership in the form of
support and funding to rebuild expiring programs, as well as
helping to fund ongoing programs in the USDA Forest
Service, Forest Health Protection.
In Canada, as recently as 1996, the Canadian Forest
Service, Forest Insect and Disease Survey Unit (FIDS)
conducted the annual overview survey across much of
Canada. They processed and digitized the survey data,
which was used by both the federal agency and the provincial
forest health specialists. Some of their other services were:
diagnostics, providing historical trends in pest populations
USDA Forest Service Proceedings RMRS-P-12. 1999
based on a 50 year record, and, providing annual national,
regional and provincial pest damage summaries. The FIDS
unit also conducted ground truthing, other special surveys
and maintained permanent sampling stations. Due to
down sizing, program reviews and philosophical changes at
the federal level, most provinces, like British Columbia,
must now conduct both their overview and operational
aerial surveys. (personal communication with Tim Ebata)
In Mexico, aerial surveys have been conducted in many
states, at both the state and federal level. The USDA Forest
Service has assisted Mexico with aerial survey training a
number of times, twice in the 1980's; in 1990, in cooperation
with Forest Health Protection and La Secretaria de
Agricultura y Recursos Hidraulicos (SARR) of the Mexican
government and in cooperation with USDA Forest Service,
Forest Health Protection and La Secretaria de Medio
Ambiente Recursos Naturales y Pesca y Protectora de Bosques
(SEMARNAP) and PROBOSQUE of the State of Mexico, in
Metepec, March, 1998.
The Present
Curren tly, there are many aerial sketch mapping programs in North America. In all three countries, the universal challenge remains the same, the ongoing struggle to find
highly qualified sketch mappers.
In Canada, the Province of British Columbia is faced
with the challenge of developing a cadre of qualified sketch
mappers, since the service and product is no longer furnished by the Canadian Forest Service. Aerial overview
surveys are now required by the Forest Practices Code
(FPC), to provide licensee land managers and District Managers with information on forest health conditions. Aerial
overview surveys are now conducted by Ministry of Forests
regional and district personnel or qualified contractors (who
are often retired FIDS observers). The Ministry of Forests,
Forest Practices Branch has developed a training package,
including workbook, video and other teaching aids to help
train new observers. The Province of Ontario still maintains
support of FIDS, who conduct aerial surveys for the province, as well as the ground plot based work. (personal
communication with Gordon Howse) Some provinces, like
Saskatchewan, only fly to sketch map specific insect outbreaks in support of suppression activities.
Across Mexico, state forest health specialists are currently developing a program or building on past aerial
survey experiences to improve their aerial survey programs. As in the United States, programs· are at various
levels of evolution, depending on the states' funding levels,
sketch mapper expertise, forest management direction, terrain, insects and diseases and vegetation. There is a strong
interest in building programs and gathering quality data.
Mexico's diverse forests and terrain makes for unique challenges in each state. Of the three countries, Mexico is the
first to hold national aerial survey training sessions, in
cooperation with USDA Forest Service Forest Health
Protection.
Presently, in the United States, the states, and the USDA
Forest Service continue to conduct aerial surveys, while
sharing the same ongoing challenges of adequate funding
and sketch mapper expertise. Because many aerial survey
USDA Forest Service Proceedings RMRS-P-12. 1999
programs have similar interests, several issues have been
worked on together. One issue, aviation safety, has been
addressed the past three years with the development of the
Natural Resource Aerial Survey Aviation Safety and Management (AS2M) training course. Another issue, information sharing, has been addressed with the formation of the
Aerial Survey Technical Working Group in November, 1996,
to provide field level input to the Washington, D.C. Office
and Staff Directors regarding issues of interest to the various aerial survey programs. The goals of this working group
are: (1) ensure safe aerial survey programs, (2) to conduct
each program in the most cost efficient and highest quality
manner to meet customers needs, and (3) to communicate
information about aerial surveys to appropriate audiences
in a timely manner. This working group has become a sort
of support group for sketch mappers of all agencies. At the
1998 meeting, a British Columbia representative attended
and shared the British Columbia training package. This
working group meets annually and welcomes sketch mappers from any country or agency.
A major supporter of aerial surveys in the United States
is the Forest Health Monitoring Program. FHM has become
a national leader in mentoring new aerial survey programs
and assisting ongoing programs. The FHM understands the
importance of aerial survey programs in the United States
and the importance of collecting aerial survey data for local,
regional and national needs. FHM has become an additional
primary customer of aerial survey data. While realizing
aerial survey limitations, FHM sees value in the vast information gathered each year and over past years (historical).
Recently, it has taken on the challenge of bringing the many
and varied programs to a common goal of implementing
national aerial survey standards for sketch mapping and
geographic information system (GIS) processing. These standards include; mapping and reporting a defined set of tree
damage types (including mortality and defoliation), damage
severity and damage pattern. This national, regional and
state combined effort to implement aerial survey standards
was done so that each local program could still meet their
needs, yet tier to the national level, so all combined data
could be utilized. This example of cooperation, for the good
of all programs, can serve as a model to other countries. This
cooperation has also resulted in support for improving data
quality as well as standardizing shared data. And the agreed
upon method to improve the quality of aerial surveys was to
support sketch mapper training, certification and annual
preseason "calibration and conformity" sessions.
The Future
With the growing interest in forest ecosystem resource
status and change at national and global scales, aerial
surveys can provide rapid and low cost per area assessments
of disturbance events that can complement other data. As
stated in this symposium's notice, all three North American
countries are reassessing and redirecting their inventory
and monitoring programs, making this a golden opportunity to coordinate efforts to enhance the quality,
interoperability and availability of aerial survey data and
information. With the understanding of the value, as well as
the limits of large geographical aerial surveys and the
61
importance of well qualified aerial sketch map observers
and programs, our three countries can work together to
capture and share data on a continental scale.
What is currently developing in the present will be the
ground work affecting the future opportunities for quality
and shared information. Additional training is planned
between the USDA Forest Service, Forest Health Protection
and Mexico's SEMARNAP sketch mappers in the northwest
United States in 1999. Geographical positioning system
(GPS), GIS and digital map base technology are being
utilized to develop computerized sketch map tools. With
little written information available about aerial survey
protocol, Forest Health Monitoring and Forest.Health Protection are sponsoring the writing of a national procedures
guide to conducting aerial surveys. This guide would be of
value to sketch mappers in all countries that conduct aerial
surveys.
Conclusions
-----------------------------------
Eaton, C.B., 1942. The adaptation of aerial survey methods to the
forest loss survey. USDA Bureau of Entomology and Plant Quarantine, Berkley, CA., unpublished report.
Klein, W.H., S.Tunnock, J.G.D. Ward and J.A.E. Knopf. 1983.
Aerial sketch mapping. USDA Forest Service, Methods Application Group, Ft. Collins, CO. 15 p.
McConnell, T.J. (ed.). 1995. Proceedings aerial pest detection and
monitoring workshop. USDA Forest Service, Northern Region,
Forest Pest Management, Rpt. 95-4. 103 p.
Miller, J.M., 1926. Report of aerial photography as a method of
mapping yellow pine areas to show losses caused by bark beetles.
Forest Insect Laboratory, Stanford University, CA. (ms.).
Ministry of Forests, 1997. Aerial overview surveys, forest insects
and diseases training program, Participant's Guide, British Columbia Forest Service, version 1.1, 71 p.
Unknown, History of the use of aircraft in Forest Service work,
USDA Forest Service, Region 1, Missoula, MT. 9 p.
Wear, J.F. and W.J. Buckhorn, 1955. Organization and conduct of
forest insect surveys in Oregon and Washington, USDA Forest
Service, Pacific Northwest Forest and Range Experiment Station, 40 p.
---------------------------------------------------------------------
Again, aerial survey data is only as good as the sketch
mapper. All three countries have similar ongoing needs for
sketch mapper expertise, suitable map bases and safe
aerial survey programs. Standardization needs to be implemented internationally. Forest Health Monitoring Program,
states and USDA Forest Service will strive to be leaders in
North America to ensure that sketch maps surveys are a
quality method of detection and monitoring offorest ecosystem resources. Now is the time for Mexico, Canada and the
United States to work together to share methods, expertise,
and develop a strategic plan to conduct aerial surveys across
the forests of this continent in a standardized and quality
manner. Each year that a forest is not surveyed, potential
valuable information on forest change is lost forever. Using
Forest Health Monitoring's example and assistance, this
can be accomplished.
62
Literature Citations
Directory Personal Communications
Tim Ebata
Forest Practices Branch, BC Min. of Forests
PO Box 9518 STN PROV GOVT
Victoria, BC V8W 9C2
Gordon Howse
Forest Health
Natural Resources Canada
Canadian Forest Service
Great Lakes Forestry Centre
1219 Queen Street East
PO Box 490
Sault Ste. Marie, Ontario P6A 5M7
USDA Forest Service Proceedings RMRS-P-12. 1999