This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
NOWMBES 1954
845
Literature
Cited
nificantly related to susceptibility height is a cumulative measureof
to weevil injury, moresothan d.b.h. annual phloem production over the 1. GRAHAM,S. L. 1926. Biology and. conTrees with thin bark were less sus- period of exposure of the tree to
trol of the white pine weevil. Cornell
Agric. Expt. Sta. Bul. 449, pp. 32.
ceptible than trees with thick bark, weevil injury.
H. B. 1952. Unpublished
In even-aged stands, among trees 2. KR•m,
although there was considerable
data, New Hampshire Agric. Expt.
variation
due to other unknown
of equal diameter and height, those
Sta.
factors.
with the thinnest bark may be ex- 3. MAcALONEY, H. J. 1930. The white
pine weevil (Pissodesstrobi Peck).
Bark thickness is considered to
pected to be least injured by the
Its biology and control. N.Y. State
be important because of the •rela- white pine weevil. In forest geCollege of Forestry, Tech. Pub. 28,
tion of the thicknessof phloem in netics:research,this may be used as
pp. 87.
the terminal shoot to weevil attraca guide in the selectionof trees to 4. SP•JRR,S. H., and R. B. FRmN•). 1941.
Compressionwood in weeviled northtion, oviposition, and larval devel- be tested for inherited resistance to
ern white pine. Jour. Forestry 39:
1005-1006.
opment. Bark thickness at breast weevil injury.
LightningFire Researchin the
J. S. Barrows
Chief, Division of Fire Research,
Rocky Mountains
Intermountain
Forest
and
Range Experiment Station,
Missoula, Montana.
LIGHTNINGis the major cause of anticipated from other forest pro- and action of lightning in mounfires in Rocky Mountain forests. tection organizations and several tainous country, and atmospheric
research where a mobile field labThe lightning fire problem is the collegesand universities.
An active field program is un- oratory will be usedto explorethe
prime target of a broad research
program now known as Project derway on two of the six research relationship of such factors as intasks now charted for Project Sky- comingand outgoingradiation,soil
Skyfire.
fire.
During the 1953 fire seasona and air moisture, and atmospheric
The aims of Project Skyfire are
broad in character. First, it hopes cloud survey was initiated in the
to gain a better understanding of northern Rocky Mountains.
the occurrence,behavior, and con- Throughout each day of the fire
trol of lightning fires. Eventually, season observers at 25 national forafter fundamental studies provide est fire lookout stations have been
necessarybackground, Skyfire ex- reporting on the development,
pects to test the possibility of pre- movement,and action of cloudsas-
sociatedwith lightning storms.
A secondmajor task now underway is observationand analysisof
the jet stream--a zone of globecircling winds in the substratosphere which may be related to
1 i g h t n i n g occurrence and fire
weather patterns. Attempts are beents and facilities of a score of
ing made to map the jet stream
private, state, and federal agencies.
through observationof certain cirSkyfire has been initiated as a corus and altocumulus
clouds often
operative enterprise of the Interassociatedwith this river of highmountain Forest and Range Exvelocity air. In both the jet stream
periment Station and the Munitalp study and the cloud survey, timeFoundation, a private researchor- lapse motion-picture cameras are
ganization dedicated to the ad- being used to record the action of
venting or reducing the severity of
lightning fires through cloud-modification operations.
Accomplishmentof these aims is
expected to be achieved through a
cooperative r e s e a r c h program
which capitalizes on the special tal-
vancement
of basic studies of me-
teorology. Also assisting in the
project are Region i of the U.S.
Forest Service, the National Park
Service, the U.S. Weather Bureau,
and the General
Laboratory.
Electric
Research
Future assistance is
clouds.
Future
research
tasks will
in-
nuclei and electricity to lightning
and fire behavior. Finally, after
these tasks have provided a foundation of basic knowledge, field
tests will be made of methods for
preventing or reducing the severity of lightning fires.
The Lightning Fire Problem
The reasons for
a research un-
dertaking of the scopeof Project
Skyfire are written across vast
burned
areas in the 120 million
acres of Rocky Mountain forests
requiring
protection
fromlightning
fires. During the 5-year period
1948--1952 over 17,000 lightning
fires occurred in the ten Rocky
Mountain states. The average an-
nual load of 3,500 lightning fires
amounts to .63 percent of the total
number of fires occurring in the
rugged mountain country ranging
northward
from Arizona
and New
clude analysis of fire-weather rec-
MexicothroughIdaho and' Mon-
ords obtained
tana.
from
some 150 fire
danger. rating stations, study of a
cloud-breedingarea to gain a better understanding of the origin
Inthe40odd
years
oforganized
forest protection in the Rocky
Mountains m a n y advancements
846
JOURNAL OF FORES•rRY
have been made in lightning fire
control. Fire danger rating sys-
tem•originated
here.Fire weather
ests. Under critical conditions individual forests in the southwest
and the northern Rockies have been
forecasting, better transportation hit by nearly 200 fires from a
to back-country areas, improve- single storm.
The bunching of a large number
ments in fire equipment, and sysof
fires in a short period places
tematic fire control planning have
all contributed
to more effective
great stress on fire-control forces.
protection. More recently the Economicfactors prevent the desmokejumper program and wide- sign of fire-control organizations
spreaduse of aircraft are spectac- that are constantly mobilized to
ular examplesof continued prog- meet these overloads. ]•conomical
and effective fire control in lightress.
ning
country calls for great flexiThe increasing demands upon
bility to rapidly expand or contheforestresources
of thisreg!on
point to the need for still greater tract detection and suppression
assurancethat lightning fire con- forces and great mobility to move
trol will be generallyeffective.The
very nature of widespread dry
lightning stormsover rugged forested country indicatesthe great
potential for conflagrations.Since
the three-million-acre burn of 1910
these forces to zones of intensive
activity. These principles of lightning fire control have long been
recognized.However, their full application requires knowledge of
whenand wherelightningfiresmay
survey designed to find out when
and
where
cumulus
clouds form
and to chart their life cycle from
initial formation to the lightning
stage. A special objective is to
identify cloud-breedingareas where
more detailed
studies can be made
of lightning and lightning fires.
The eloud survey being made in
the
Northern
Rocky
Mountains
utilizes existing facilities at forest
fire lookout stations to obtain
data
for researchpurposes.Prior to the
1953 fire season, lookout-firemen
from the 25 stations in the observa-
tion network attended a special
training school to receive instruction
in
cloud
identification
and
general survey techniques. Each
day during the fire seasona special
form filled out at cloud-survey sta-
tions recorded the story of clouds
arid lightning. In addition, during
especiallyinteresting days a brief
what factors will influence ease or
flash report transmitted by radio
difficulty of control. Project Sky- from each survey station enabled
fire is directedat thesebasic ques- the Project Skyfire staff to obtain
tions and in addition will investia quick picture of cloudaction and
gate methods for reducing great potential lightning danger over an
area of 30 million acres.
overloadsof lightning fires.
Recent developments point to
The Project Skyfire cloud survey
possibilitiesof achieving a better is in a pioneer stage, but' already
in the northern Rockies,it hasbeen start, how many may start, how
evident that superbly organized they will behaveonce started, and
and executedfire controlprograms
are essentialL No less an effort can
assure the safety of the region's
resourcesor the lives and property
of its peopleForesters who have engaged in
lightningfire controlprogramsrecognize that many of the advancements made to date have been the
understanding of the lightning
there
phenomena and of the basic mete-
Clouds are dynamic indicators of
weather and lightning conditions.
obviousthings to do. To a large orological factors influencing the
degree the cream has been skimmed
cause and subsequent behavior of
and in the future, needed prog- lightning fires. Advances in the
ress will
be more
difficult.
The
road ahead dependsheavily upon
research progress in still unsolved
lightning fire problems.
Lightning fires have certain
characteristics indicating requirements .for successfulfire fighting
and focu•ssing
attention on research
priorities. One of the most impor-
scienceof meteorologyare providing new information .on Cloudfor-
are indications
of its value.
Results to date show that it is feasible to chart the action of clouds
and lightning from fire lookout stations.
The
information
thus
ob-
mations,cloudphysics,atmospheric tained provides research workers
nuclei, and air movements. Mete- with a new tool for exploring the
orologistshave only recently begun lightning fire phenomenon. Furintensive study of the jet stream thermore, it is being demonstrated
and of the relation of this zone of
that a network of cloud-survey stahigh-velocityair to weather condi- tions ean provide fire-control ortions. Of special significancewith ganizations with useful informatant of these characteristics is the
respect to possible lightning pretendency for a great number of vention is the recent work of Lang- tion for advance location of fire
lightning fires to occur in a short muir, Schaefer, and others of the occurrence zones, dispatehing fire
period. Northern Rocky Mountain Project Cirrus group in weather fighters and evaluating probable
fire behavior.
forests have been seized by some
400 lightning fires in 24 hours and
over 1,500 in ten days. Over a
span of 15 fire seasonsthere have
been 76 days when 50 or more
modification
and
cumulus clouds 2.
treatment
of
Jet Stream Study
A secondmajor activity of Project Skyfire is study of the jet
lightning fires started in Montana Project Skyfire has been a cloud stream. The great high-altitude
winds now known commonly as the
and northern Idaho national forjet stream may be visualized as a
2Schaefer, Vincent. J. Final report
1Barrows, J. S. Forest fires in the
river of air flowing around the
Northern Rocky ' Mountains. Northern Project Cirrus, Part 1, Laboratory, Field,
Rocky Mountain Forest & Range Experi- and l•ligh•; Experimen•;s. General Elec- world on a meanderingcoursefrom
tric Research Laboratory Report No.
ment Station Paper No. 28, 251 pp.,
west to east and varying in width
illus. 1951.
RL-785. 170 pp., illus. 1953.
Cloud Survey
The first major field activity of
NOVEMBER1954
847
from ten miles to several hundred.
The altitude of the main axis of
Project Skyfire. Additional phases
of the planned research program
including fire weather analyses,
atmosphericresearch,and study of
parallel bands of clouds showing a cloud-breedingarea will be iniwaves or billows at right angles to tiated as soon as the necessary
lenticular tapered like a lens, and
often layered in the sky like a
stack of leaning flapjacks, and altocumulus billows appearing as
the jet stream may vary from 20,000 to 40,000 feet. During the fire
season months, two or more jet
streams may be present over the
westernUnited Statesand Canada, their motion.
although from meager information
As an additional phase of the
now available it appears that the cloud survey, the 25 fire lookouts
usual pattern is for onIy one par- have been recording daily observaticular path of air to form the true tions of jet stream clouds. This inmain axis.
formation will provide the basisfor
While specificknowledgeof the m a k i n g generalized jet-stream
jet streamis still very limited, in- maps which in turn will be comdicationsare that thesegreat winds pare•dwith the daily high-altitude
may be closelyrelated to many wind maps furnished by the
lightning and fire behaviorfactors. Weather Bureau. The jet stream
Under somejet-stream conditions is also being studied in relation to
lightning may possiblybe pre- lightning occurrence,wind velocity
vented or reduced by wind action at ground level, air and fuel moisshearingoff the tops of towering ture, and burning index.
cumulus clouds. Under other jet
stream conditions the lightning
Time-lapse Photography
storm may possibly become more
As an important part of both the
severe. Of great interest to forcloud survey and the jet-stream
estersis the apparent relationship
study, time-lapse motion-picture
betweenthe jet stream and periods
cameras are being used to record
of extremelydry and windy weather. There are strong possibilities cloud phenomena. The time-lapse
that knowledge of the jet stream motion-picture camera enables
cloud action, which is difficult to
may answer some of the major
problems of predicting fire be- appreciate with the naked eye, to
havior in Rocky Mountain forests. be speededup and witnessed as a
Observationsmade by Schaefer spectacular series of events. The
show that certain cloud types are special cameras provided by the
often associatedwith the jet stream.s Munitalp Foundation enable an
This association between cloud for-
hour
ßmations•and high-altitu,d,e
winds
pressed into two minutes of film
time. A battery-operated electric
solenoid automatically opens the
camera shutter every two seconds.
During the summersof 1952 and
1953 over 5,000 feet of time-lapse
color motion-picture film has been
exposedat fire lookout stationsin
Rocky Mountain national forests
and parks. These motion pictures
provide a useful meansfor studying cloud,lightning, and jet stream
activity. This program is expected
to provide a film library documenting significant events in Rocky
points to the exciting possibilityof
observing and mapping the jet
stream by visual methods. In turn•
forestes may find that jet-stream
clouds serve as indicators
of fire
weather and lightning conditions
and signal some of the probable
patterns of fire behavior.
Cloud forms of the jet stream
of cloud
appear to be of four types. The two
high cloud types are long streamers
of cirrus moving at high velocity
and great patchesof cirrocumulus
made up of cells showing small
waves and ripples. The middle Mountain
cloud types are the altocumulus
•Schaefer, ¾•ncent J.
the
jet
Sweden.
stream.
1953.
Cloud forms of
Tellus ¾. Stockholm,
action
to be com-
skies.
Future
Studies
The cloud survey and the jetstream study are the first efforts of
facilities and research staff become
available.
Each of these research
tasks should yield segmentsof the
fundamental knowledge needed before work begins on the ultimate
goal of attempting to answer the
key question--can lightning fires
be prevented ?
The possibility that lightning
fires may be prevented or reduced
in severity stems from the pioneer
work of Langmuir and Schaefer
and from the operational experiencesof many others in the cloudseeding field. It has been demonstrated in the laboratory and the
natural atmosphere that cumulus
cloud structures may be modified
through the introduction 'of such
nuclei as dry ice and silver iodide.
These demonstrationspoint to the
desirability of testing cloud modification as a means of reducing
lightning occurrence. Experience,
in experimental meteorologyindicates that it may be possible to
overseed mature storms in an effort
to eliminate the super-cooledclouds
associatedwith lightning, or to ini-
tiate the precipitation cycle in
growing cloudsbefore they become
large enough to produce lightning.
The
exact
course
of events
and
the results of the research of Proj-
ect Skyfire remain largely unknown.
Recent advances in meteorology
and forestry, and the continuing
problem of lightning fires make
this program a timely undertaking.
The possibilitiesfor lightning prevention are worthy of full investigation. Whatever may be the results of these tests, it appears that
the very nature of the required researchmay yield new knowledgeof
lightning fire occurence,behavior,
and control. Future protection of
Rocky Mountain forestsdependsin
part on this knowledge.