Proceedings: 9th Tall Timbers Fire Ecology Conference 1969
Lightning Effects on
The Forest Complex
ALAN R. TAYLOR, RESEARCH FORESTER
USDA Forest Service
Intermountain Forest and Range Experiment Station
Ogden, Utah
Stationed at N orthern Forest Fire Laboratory
Missoula, Montana
is an ever-present part of our natural
environment. Brooks (1925) stated that the earth experiences 44,000
thunderstorms per day and that some 1,800 storms are in progress at
any given moment. The U.S. Department of Commerce (1966)
estimates that these storms produce, collectively, 100 cloud-to-ground
lightning discharges each second-or more than 8 million discharges
striking the globe each day. If these discharges were evenly distributed over the earth, some half million of them would strike in
the world's 8,000 million acres of forested lands every day. These
estimates support Viemeister's (1961)· claim that lightning strikes
thousands of trees around the world every day.
American forestry literature lends further support. From an early
survey that included all U.S. National Forests of his day, Plummer
(I912) reported that more than 76,000 trees were damaged by
lightning in a 4-year period. Wads\vorth (1943) noted that lightning accounted for one-third of the timber mortality in a 15 -year
study in the ponderosa pine (Pinus ponderos,1 Laws.) forests of
LIGHTNIKG
127
Proceedings: 9th Tall Timbers Fire Ecology Conference 1969
ALA~
R. TAYLOR
northern Arizona. Ffolliott and Barger (1967), also working in
northern Arizona, found that lightning had damaged fully 10 percent of the 634 sawtimber trees they examined. In western Montana,
Taylor (1964a) tallied some 1,000 lightning-struck live Douglas-fir
(Pseudotsuga 111enziesii var. glauca (Beissn.) Franco) trees on 10,000
acres of forest land, and Johnson (1966a) reported that lightning
directly accounted for 4 percent of the mortality of 406 old-growth
ponderosa pines examined in western .i\10ntana.
In Pennsylvania, Nelson (1958) found lightning the greatest single
cause of mortality (25 percent) of 1,300 mature eastern hemlock
(Tsuga canadensis Carr.) trees. Similarly, Trousdell (1955) found
lightning one of the greatest single causes of death of loblolly pine
(Pinus taeda L.) seed trees in Georgia, and Reynolds (1940) claimed
that lightning was directly or indirectly responsible for fully 70 percent of the total volume loss in pine forests in southern Arkansas.
Finally, Vogi (1968) reports that more than 30 percent of the
Jeffrey pines (Pinus jeffreyi Grev. and Balf.) growing at elevations
between 7,000 and 8,000 feet on Mt. Pinos in southern California
showed effects of lightning discharges.
DIRECT EFFECTS
This brief review confirms that lightning strikes frequently in
forested areas of this country. Now let's consider some of the consequences.
FOREST WILDFIRES
Wildfire is probably the most important immediate consequence
of lightning in North American forests (Fig. 1). Annually, lightning
causes some 10,000 to 15,000 forest fires in the United States. These
fires damage commercial timber, watersheds, wildlife, forage, and
outdoor recreation values. The total economic loss is difficult to estimate, but lightning fire suppression costs alone may amount to $50
million per year (Barrows, 1966).
The problem is most acute in the Western States, where 70 percent
of all forest fires are caused by lightning. There a single thunderstorm can start tens of fires in minutes over miles of virtually inac128
FIG. 1. Lightning discharge produced by a small but hard-hitting thunderstorm,
typical of those occurring in the northern Rocky l\lountains. Left-hand channel
ignited crown foliage of grand fir tree on ridgetop, Sept. 6, 1966. USDA Forest
Sen'ice photo.
cessible terrain. In August 1961, lightning started nearly 600 fires in
one 3-day period on the National Forests in J\lontana, Idaho, Oregon,
and \ Vashington (U.S. Dep. Agr., Forest Service, 1962). This characteristic consequence of lightning-many fires in a short timetaxes fire suppression agencies beyond all reasonable limits of manpmver and equipment, and suppression costs soar.
129
ALAN R. TAYLOR
The fire-setting discharge :-Most lightning discharges that strike
forested lands do not start fires. Why? Certainly, many discharges
strike noncombustibles on the forest floor. But many others apparently travel through highly combustible forest fuels yet cause no
fire. This suggests that fire-setting discharges may somehow differ
from those that do not cause fire.
The hypothesis that lightning fires are caused by a special type
of electrical discharge is not new. Working with laboratory sparks,
McEachron and Hagenguth (1942) hypothesized that explosive
effects of lightning discharges result from very short-duration return strokes such as those depicted by the sharp "spikes" in the
oscillograph record of the discharge (Fig. 2). The traces here show
changes caused by the lightning discharge in the atmospheric electric
field. McEachron and Hagenguth reasoned that ignition is most
r-
--+j
100
milliseconds
RI
R2
R3
FAST FIELD CHANGE
SLOW FIELD CHANGE
FIG. 2. This oscillograph record shows fast and slow electric field change traces
of a discharge that started a forest fire in western Montana on August 11, 1968. Note
the long-continuing current phase following the R3 stroke.
130
LIGHTNING EFFECTS ON THE FOREST
likely to occur when a discharge contains, in addition to one or
more fast return strokes, a long-continuing current phase in which
current flows continuously in the lightning channel for a relatively
long duration. This is shown following the third return stroke in
Figure 2 (R3), where the upper trace decays slowly to the smooth
baseline after some 100 milliseconds of continuous current flow.
McEachron and Hagenguth's views apparently were accepted by
other workers (Berger, 1947; i\1alan, 1963; Loeb, 1966), but until
1967 only one published work (Norinder et al., 1958) documented
characteristics of two lightning discharges and compared their ignition effects.
We recently documented the characteristics of 10 lightning discharges that started forest fires in western Montana (see Fuquay
et ai., 1967 for data on seven of them). Nine of the 10 strikes exhibited the characteristic long-continuing current phase proposed by
McEachron and Hagenguth. One of these nine discharges, recorded
in Figure 2, started the forest fire photographed just minutes after
ignition and shown in Figure 3.
These 10 events, obtained from six storms during the period 196568, support the hypothesis that most lightning fires are caused by
discharges having a long-continuing current phase.
Mechanisms of lightning-caused ignition :-Lightning discharges
develop high temperatures in their ionized paths between cloud and
ground. Peak color temperatures of the channel in air range from
about 21,000° to 31,000oK. (Zkivlyuk and Nlandel'shtam, 1961;
Prueitt, 1963; Uman, 1964 and 1966). i\1uch less is known about the
. peak temperatures developed in and near the ground terminal of the
lightning discharge, but the literature records evidence of energy
sufficient to melt and vaporize several metals (Bellaschi, 1935), to
fuse sand particles (Schonland, 1950), and to ignite forest fuels
(Barrows, 1951 a).
Until now, little has been published about the forest fuel ignition
mechanisms of lightning. The subject has only peripheral interest
for most workers in lightning research, and to date no definitive
publication has appeared. Writers of general texts on lightning have
given only perfunctory attention to the problem, usually indicating
that Joule heating is the primary mechanism involved. Thus, the
131
ALAN R. TAYLOR
FIG. 3. This incipient forest fire was started by the discharge depicted in Figure 2.
This photograph was taken minutes after the discharge was recorded at ground
station 17 miles away. USDA Forest Service photo.
state of knowledge about ignition mechanisms of forest fuels by
lightning is summarized in this generalization: The passage of a
lightning discharge current through high-resistance forest fuels may
result in ignition if the current flow is sustained long enough to heat
the fuels to their ignition points.
Other mechanisms may also result in ignition by lightning. Research just now beginning at the Northern Forest Fire Laboratory
will examine the yarious processes of heat transfer for forest fuel
ignition by lightning.
Forest fuels :-Considerina
the liahtnina-fire
phenomenon in terms
b
b
b
of its several components-the discharge, the fuels, the antecedent
and attendant meteorological environment, the topographical environment, and the fire itself-none is more complex and less understood than the fuels-particularly their role in ignition.
We know little beyond the fact that forest fuels are susceptible
132
LlGHTXIXG EFFECTS ON THE FOREST
to ignition by lightning. Intuitively \\"e feel that, given a "suitable
discharge" to a natural fine fuel particle or bed, some form of
pyrolysis or ignition will probably occur and, given some range
of combined fuel and meteorological conditions, the ignition will
either spread to surrounding fuels or become extinguished.
Which fuels are most frequently first ignited by lightning? Plummer (1912), probably the first to survey and publish a comprehensive report on the lightning fire problem, concluded (p. 30): " . . .
the majority of forest fires caused by lightning striking trees is due
to the presence of dry duff, humus, or litter at the base of the tree."
Plummer's statement has been repeated from other areas including
the pine-forest belts of Russia (Gribanov, 1955). Likewise Nlorris
(1934) tabulating 5,000 Forest Service lightning fire reports from
22 forests in Washington and Oregon, found that needles and duff
were the fuels first ignited in 42 percent of the fires. However, he
ranked live trees as the most frequent first-ignited fuel on two forests
and snags as the most frequent on three others. He reported that
shrubs were less important than live trees and snags, and that rotten
wood and logs or stumps were seldom the ignition material for lightning fires. This statement contrasts with that of Fobes (1944), who
claimed that lightning-caused fires in Alaine usually started in the
punky wood of stumps and tree stubs.
Barrows' (1951 a) comprehensive treatise on fires in the northern
Rocky i\lountains classified 11,835 fires by timber type, according
to material first ignited (table 27, p. 86). Importance of these fuel
types was indicated by their frequency as first-ignited fuel, as follows:
Snags
Duff on ground
\Vood on ground
G reen tree tops
34 percent
30
"
12
"
"
10
Grass, moss on tree, slash, brush, and v,eeds followed in descending
order of frequency. Comparing all ground fuels to aerial fuels (snags,
green tree top, and moss on tree), Barrows' table shows that aerial
fuels \vere first ignited in 48 percent of all fires.
A recent 4-year Canadian survey of 3,615 lightning-caused fires
(Kourtz, 1967) shows that duff, grass, and moss were the first fuels
133
ALAN R. TAYLOR
FIG. 4. Latent lightning-caused fire smoldered in decayed heartwood of this live
Douglas-fir for 6 days before the tree collapsed and spread fire to ground fuels.
USDA Forest Service photo.
ignited in more than 60 percent of these fires. An earlier report on
the same study (Kiil and Fraser, 1962) noted that survey data from
1960 showed aerial fuels were ignited first in about 40 percent of
620 fires examined.
Komarek (I 968), reporting on lightning fires in National Forests
in California during 1966, stated that duff and snags ranked first and
second, respectively, as fuels first ignited.
This review emphasizes that most forest fuels are susceptible to
ignition by lightning. However, empirical observations on small
lightning fires in the northern Rocky lVIountains lead me to suggest
that lightning typically ignites initially only the finer particles of
any fuel "struck" by it. The situation appears roughly analogous to
the setting of a fire in a fireplace: It too must be started with fine
kindling. Some examples of this include the ignition of granular
particles of decayed wood in the hearts of trees (Fig. 4); lichens and
needles in tree crowns (Fig. 5); oleoresin deposits in tree bole in134
LIGHTNING EFFECTS ON THE FOREST
FIG. 5. Left. Lightning discharge on August 3, 1968, in western Montana damaged
the western larch, center, and ignited crown fuels in grand fir, right. Fire consumed
upper two-thirds of crown. USDA Forest Service photo.
FIG. 6. Right. Lightning discharge caused momentary ignition of volatile oleoresin
deposits on old interior ring-shake defect (dark areas above hardhat) in this Douglasfir. USDA Forest Service photo.
teriors (Fig. 6); and wood slivers resulting from old wounds when
a new lightning furrow is partially superimposed upon an old lightning scar (Taylor, 1969) (Fig. 7). The damaged face of a lightningstruck subalpine fir (Abies lasiocarpa (Hook.) Nutt.) trunk is shown
in Figure 8. In this tree the discharge created its own kindling, raising and charring hundreds of wood fibers on the surface, but no
"forest fire" resulted. This phenomenon, apparently not heretofore
reported in the literature, has been observed frequently by the author
on both fired and unfired lightning-damaged conifers in the West.
Other examples of lightning creating kindling material include the
splintering of bare snags, poles, and live tree boles.
The latent (holdover) lightning fire:-One of the most common
135
ALAN R. TAYLOR
FIG. 7. Left. New lightning damage superimposed on 6-year-old lightning scar on
western larch fired by a discharge in western Montana. Lighter portion of furrow
in upper part of photo is new damage. Ignition occurred on another superimposed section just out of picture to the right. USDA Forest Service photo.
FIG. 8. Right. Discharge split this subalpine fir, raising and charring the tips of
wood fibers on damaged surfaces. No "forest fire" resulted. USDA Forest Service
photo.
but least understood lightning fire phenomena is the so-called "holdover" or latent lightning fire. Such a fire goes undetected for several
hours or days (occasionally weeks and months), apparently smoldering in or surrounded by fuels too wet or otherwise unable to support
flaming combustion. When fuel and weather conditions are right,
the fire spreads, produces smoke and flames, and may be detected
(Fig. 4).
136
LIGHT~ING
EFFECTS ON THE FOREST
How often latent lightning fires occur depends upon one's arbitrary
selection of elapsed time between origin and discovery of the fire.
F or example, one might classify as latent fires all those not discovered
within 12 (or 48, or 72) hours after estimated time of origin. The
tabulation below shows the percentages of lightning fires not discovered within those specified time periods, as reported by several
wnters.
Area
NF* R-1, E zone
NF, R-l, \Y zone
NF, R-5
NF, R-6
NF, R-1 (all)
Canada
Lightning
Fires Lndiscovered
'Yithin
Hours:
12 24 72
45
36
42
41
61
20
21
33
22
23
40
6
9
10
10
II
Basis,
No. Fires
Years of
Record
Source
2,020
14,348
4,363
5,300
14,489
3,615
1931-45
1931-45
19II-20
1940-44
1950-65
1960-63
Barrows (1951b)
Barrows (1951b)
Show and Kotok (1923)
Morris (1948)
Losensky**
Kourtz (1967)
* National Forests of the Forest Service region indicated, e.g., R-l.
** Unpublished data tabulated in 1967 by B. J. Losensky; on file at
the Northern
Forest Fire Laboratory, Missoula, Montana.
These data suggest that some 40 percent of all lightning-caused fires
in the far Western United States are undiscovered 12 hours after
estimated origin; that about 25 percent are still undiscovered 24
hours after origin; and that 10 percent remain undiscovered 72 hours
after origin. Apparently the situation in Canada is similar, although
the percentages differ in two of the elapsed time classes. Thus, a considerable percentage of fires must be classed as latent fires even if 72
hours is the selected time-lapsed boundary.
Little is known about the fuel and weather conditions attending
this type of fire. Most writers suggest that precipitation accompanying lightning keeps fires dormant in duff (i\1orris, 1948; Bennett,
1958) or snags (Show and Kotok, 1923) until these fuels dry out
sufficiently to support flaming combustion. This seems true enough,
but the generalization must be examined critically and many obser137
ALAN R. TAYLOR
FIG. 9. Left. Lightning struck this Douglas-fir and extensively damaged the back
side of the trunk (not sho\,,;n) and remond outermost bark scales from about half
the circumference of the trunk (white patches, entire length shown). Charred
bark on lower bole resulted from earlier ground fire not associated with lightning
damage. USDA Forest Service photo.
FIG. 10. Right. Douglas-fir shows three spiral lightning furrows (upper left, middle,
and lower sections of bole) caused by single lightning event. Here lightning removed bark only, exposing outer wood. USDA Forest Service photo.
vations must yet be made if we expect to understand and predict the
occurrence of this phenomenon.
So much for the major facets of lightning-caused wildfire. I turn
now to some non fire lightning effects. As we shall see, these more
subtle and less-known lightning effects collectively take a significant
toll of forest resources.
138
LIGHTNING EFFECTS OX THE FOREST
TREE INJURY AND MORTALITY
Individual trees:-Trees frequently become the ground terminals
of lightning discharges. Though lightning does not always strike the
tallest trees in a forest, it often does (Taylor, 1964a; Kourtz, 1967);
and these trees are often the most commercially valuable ones in the
stand (Wadsworth, 1943; Johnson, 1966b). Even though most trees
struck by lightning probably are not killed outright (Taylor, 1964a),
they often suffer loss of increment (Georgievskij, 1963) and volume
(Wadsworth, 1943) through structural damage and become susceptible to attack by insects and diseases (Lindh, 1949; Kourtz, 1967).
Some trees survive several discharges over the years (Plummer,
1912 ; Taylor, 1969)~ but others die soon after they are hit; sometimes they show no outward signs of injury (Stone, 1914; Stevens,
1916; Hawley, 1937). On still other trees, lightning removes only
the outer bark flakes· in its path along the trunk (Dodge, 1936). This
superficial flaking is sometimes observed on severely damaged trees
(Fig. 9). In conifers the most common damage is a shallow, uniform
furrow 2 to 10 inches wide that spirals along the trunk exposing only
the outermost layers of sapwood in its path (Vanderlinden, 1907;
l\1urray, 1958; Taylor, 1965). Some discharges cause as many as
three such furrows at once (Fig. 10). But greater damage is fairly
common; and when wood is removed from the bole, it is usually
ejected as two parallel slabs or slivers of nearly equal dimensions.
Figure 11 shows the locations and distances of two slabs, A and A',
ejected from a Douglas-fir tree, and Figure 12 indicates their respective original positions on the bole. Sometimes lightning virtually
destroys a tree (Stevens, 1921; McEachron, 1940; Vie meister, 1961)
(Fig. 13).
Damage to the tree bole is the most obvious, but all parts of the
tree are vulnerable. Sometimes lateral roots are severed at the base of
a lightning-struck tree (Fig. 14). Branchlets and needles are often
damaged by flying bark and wood debris (Fig. 15). Clusters of
conifer needles several feet from a damaged bole surface may be
damaged by finely divided particles of outer bark ejected from the
bole by the electrical discharge (Fig. 16). On some trees several
hundred clusters of needles are damaged this \vay.
139
FIG. 11. Pair of 8-foot-long wood slabs marked A and A' was removed from tree
(right, background) by discharge to the locations shown. Parallel-slab phenomenon
is typical in western conifers where wood is removed by lightning. USDA Forest
Service photo.
FIG. 12. The pair of slabs in Figure 10 is shown here leaning against parent
tree. Symbols indicate identifying limb stubs that show respective original positions of slabs on tree. USDA Forest Service photo.
140
FIG. 13. "Lightning is not averse to striking more than once in the same spot-but
frequently once is sufficient." (McEachron 1940). Douglas-fir tree was severed
cross sectionally and split longitudinally; one 12-foot chunk was hurled 60 feet,
and short-duration ignition occurred on the portion left standing. USDA Forest
Service photo.
FIG. 14. Soil excavation at base of lightning-struck ponderosa pine shows severed
lateral roots (see entire tree at arrow in Figure 17). USDA Forest Service photo.
141
FIG. 15. In this cluster of 153 ponderosa pine needles, growing 4 feet from lightning-damaged bole surface, 136 needles were damaged, showing a total of 613 impact
sites from fiying bark particles. Sixty of these impact sites contained embedded
particles of outer bark. USDA Forest Service photo.
FIG. 16. This particle of outer bark is embedded in a needle from damaged cluster
shown in Figure 15. USDA Forest Sen-ice photo.
142
LIGHTNIXG EFFECTS ON THE FOREST
Tree groups :-The preceding discussion was directed primarily
toward the familiar situation wherein a single tree is struck by
lightning. But in many parts of the world, lightning injures and
kills groups of trees in a stand as well as individuals. In a typical
group kill, external damage is usually visible on only one or two
trees in or near the center of the group (LaRue, 1922; Murray,
1958). Other trees around the damaged stems die or show decline,
often in a circular pattern (Hauberg, 1960; Anderson, 1964).
Tree group mortality caused by lightning has seldom been reported in the United States (but see Stevens, 1918 ; Jackson, 1940;
Komarek, 1964); but the literature abounds with such reports from
other parts of the world including Sumatra (LaRue, 1922), Honduras
(Reinking, 1930), England (Peace, 1940; Shipley, 1946), New Zealand (New Zealand Forest Service, 1954), Scotland (i\1urray, 1958),
Borneo (Anderson, 1964; Brunig, 1964), and Australia (Minko,
1966) .
Review of the literature on group mortality cited above indicates
that those groups apparently were damaged by lightning alone. Curiously, another virtually independent body of literature on forest
entomology (discussed in the next section) attributes group killing
of trees entirely to bark beetles initially attacking a single lightningdamaged tree in the stand.
INDIRECT EFFECTS
ATTACKS BY INSECTS
Entomologists have long knmvn that lightning-damaged conifers
apparently attract several genera of bark beetles (Coleoptera:
Scolytidae) (Hopkins, 1909; St. George, 1930; Doane et a/., 1936;
Hetrick, 1942; Miller and Keen, 1960; Dixon and Osgood, 1961;
Johnson, 1966b; Anderson and Anderson, 1968). The apparent relationship is not well understood, and little is known about frequency
of its occurrence. Most entomologists consider this problem minor in
comparison with others vying for their attention.
The theory that attacks by bark beetles OIl single lightningdamaged trees may lead to mass attacks on surrounding trees has been
long accepted (Hopkins, 1909; Reynolds, 1940; Thatcher, 1960;
143
ALAN R. TAYLOR
McMullen and Atkins, 1962) . Hodges, l studying physiological
changes in southern pines following lightning damage, noted that
26 group infestations by the southern pine beetle (Dendroctonus
frontalis Zimm.) in one township in Louisiana each contained at least
one lightning-damaged tree. Schmitz and Taylor (1969) recently
documented a case of group mortality involving lightning damage
and attack by the pine engraver beetle (Ips pini Say) in a stand of
96 young ponderosa pine in western Montana (Fig. 17). Lightning
blasted a 66-foot spiral strip of bark from the bole of the struck tree
and severed numerous lateral roots. Seventy-three trees within 80
feet of the struck tree were attacked by beetles, and 84 percent of
these attacks were successful.
On the basis of their observations of root damage to the struck
tree and in view of the two bodies of literature on group mortality
noted, Schmitz and Taylor suggest the possibility, as did Komarek
( 1964), that lightning may cause unobserved physiological damage
to trees surrounding an obviously struck tree, making them susceptible to beetle attack.
Understandably, entomologists' research efforts are directed chiefly
toward major insect epidemics and measures for controlling them.
However, on the basis of the U.S. Department of Commerce estimates of lightning occurrence cited earlier, it appears possible that
some 182 million lightning discharges strike on forested lands over
the world each year. Hence, the role of lightning in insect ecology
may be \vorth further consideration.
DAMAGE FROM DISEASES
Occasional association of lightning InJury with tree diseases has
been \vell documented (Boyce, 1920; Sharples, 1933; Furtado, 1935;
Hawley, 1937; Peace, 1962; Komarek, 1964; Hinds and Hawksworth,
1966; Kourtz, 1967). Sharples showed that the so-called bud rot in
Malayan coconut palm (Cocos nucifera) is caused by lightning injury and has killed many palms. He also supported Weir's claim
(I929) that the so-called dieback of rubber trees (Hevea brasiliensis)
1 Personal communication
(October 21, 1966) from Dr. John D. Hodges, Plant
Physiologist, Southern Forest Experiment Station.
144
LIGHTNING EFFECTS ON THE FOREST
FIG. 17. Aerial view of group kill in western Montana. Ultimately, 73 of 96
ponderosa pine saplings and poles within 80-foot radius of the mature, lightningstruck pine (arrow) were attacked by pine engraver bark beetles. USDA Forest
Service photo.
was due primarily to lightning and noted that lightning-caused root
damage could make a tree particularly vulnerable to root diseases.
V ogl (1968) suggests the possibility that cro"Wll rot of the California
fan palm (Washingtonia filifera) is preceded by lightning injury to
the terminal buds. Apparently no such claims have been made concerning crown or root diseases of conifers in the United States.
When its protective bark is removed, a tree usually becomes susceptible to infection. Hence, the large number of lightning discharges
into forested areas might be expected to open up potential courts
of disease in many thousands of trees throughout the world each year.
Most of the reports cited above suggest that lightning injuries to
trees are so infrequent as to cause little concern to pathologists or
145
ALA~
R. TAYLOR
resource managers. I suggest that, although many other forest disease
problems may be more urgent, lightning damage is a more significant
precursor of tree diseases than has been generally realized and that
the problem deserves further attention.
DISCUSSION
This paper has dealt with the lightning effects and influences that
cause primary concern in protection of the forest complex-forest
fire, mortality, injury, and damage from insects and diseases. Although
it was written within the framework of protection-oriented research,
it should not be construed to indicate that either the author or his
organization considers lightning fire and other lightning effects are
always and irrevocably harmful. Indeed as Vogi points out, some
effects of lightning are beneficial: the culling of overmature and
insect- and disease-ridden trees; the needed thinning and other
beneficial treatments of forest stands; and, apparently, even the perpetuation of certain tree species.
Regarding the little known long-range ecological effects of lightning, Komarek (1964, p. 170) states:
It is a truism in ecological thought that any environmental
force acting upon living matter, plants or animals, by a process of
natural selection, will cause those genes to be selected out of the
germ plasm or "gene banks" that will best allow that living matter
to succeed in a struggle for existence. Not only has lightning
developed fire adaptations, or as most geneticists would prefer,
selected out those "preadaptations" for the most successful existence \vith conditions created by fires; but also that plants at
least have developed similarly in regard to lightning itself. This is
to say, that the reaction to the lightning stroke and attendant
. conditions are different in different vegetations. Plants, animals,
and possibly life itself, have evolved through a long process of
natural selection in an environment where lightning and fires so
initiated have been an important factor, more important than many
ecologists may realize.
Recognizing these useful aspects of lightning effects, the aim of
forest protection research is not ultimately the exclusion of all lightning and its effects, but a greater understanding of both and the
146
LIGHTNING EFFECTS ON THE FOREST
ability to predict and exercise some control over them for the continuing benefit of mankind.
BIBLIOGRAPHY
Anderson, J. A. R. 1964. Observations on climatic damage in peat swamp forest in
Sarawak. Commonwealth Forest. Rev. 43 (2): 145-158.
Anderson, Neil H., and David B. Anderson. 1968. ips bark beetle attacks and
brood de\'e!opment on a lightning-struck pine in relation to its physiological
decline. The Florida Entomol. 51 (1) : 23-30.
BarrO\vs, J. S. 1951 a. Forest fires in the northern Rocky Mountains. V .S.D .A. Forest
Serv., N. Rocky Mountain Forest and Range Exp. Sta., Sta. Pap. 28, 251 pp.,
illus.
- - - . 1951b. Lightning fires in the northern Rocky Mountains. Fire Control Notes
12(3):24-28.
- - - . 1966. \Veather modification and the prevention of lightning-caused forest
fires. Pp. 169-182, in: Human Dimensions of Weather Modification. W. R.
Derrick Sewell (Ed.), Chicago: Vniv. Chicago Press.
Bellaschi, P. L. 1935. Lightning currents in field and laboratory. Pp. 1468-1473, in:
Lightning Reference Book 1918-1935. New York: Amer. Inst. Elec. Eng.
Bennett, \V. D. 1958. The control of lightning-caused forest fires. Pulp and Pap. Res.
lnst. Can. \Voodlands Res. Index 106, 30 pp.
Berger, K. 1947. Lightning research in Switzerland. Weather 2 (8) :231-238.
Boyce, ]. S. 1920. The dry-rot of incense cedar. V.SD.A. Forest Servo Bull. 871,
58 pp., illus.
Brooks, C. E. P. 1925. The distribution of thunderstorms over the globe. Great
Britain i\Ieteorol. Office, Air Min., Geophys. Mem. 3 (24): 147-164, illus.
Brunig, E. G. 1964. A study of damage attributed to lightning in two areas of
Sborea albida forest in Sarawak. Commonwealth Forest. Rev. 43 (2) : 134-144.
Dixon, John c., and E. A. Osgood. 1961. Southern pine beetle: a review of
present knowledge. V.SD.A. Forest Serv., Southeastern Forest Exp. Sta. Pap.
128, 34 pp., illus.
Doalle, R. \V., E. C. Van Dyke, W. J. Chamberlin, and H. E. Burke. 1936. Forest
insects. 463 pp. New York: McGraw-Hill Book Co.
Dodge, A. W. 1936. Lightning damage to trees. Pp. 43-55, in: Twelfth Nat. Shade
Tree Conf. Proc.
Ffolliott, Peter F., and Roland L. Barger. 1967. Occurrence of stem features affecting quality in cutover southv.:estern ponderosa pine. V.SD.A. Forest Serv.
Res. Pap. R.\I-28, 11 pp., illus.
Fobes, C. B. 1944. Lightning fires in the forests of Maine. ]. Forest. 42:291-293.
Fuquay, Donald :\1., Robert G. Baughman, Alan R. Taylor, and Robert G. Hawe.
1967. Characteristics of seven lightning discharges that caused forest fires.
]. Geophys. Res. 72 (24) :6371-73, illus.
Furtado, C. X. 1935. Lightning injuries to trees. J. i\'1alayan Branch Roy. Asiatic
Soc. XIII, Part II, pp. 157-162.
Georgie\'skij, "K. P. 1963. [Damage to trees by lightning.] Lesn. Hoz. 16(10) :47-50.
Gribanm', L. "K. 1955. Grozovye Yavleniya i Leshye pozhary. [Thunderstorms and
forest fires.] Botan. Zh. 11 0) :429-432, illus. V.SD.A. Forest Servo trans!'
Hauberg, P. A. 1960. Lynnedslag i skov. [Lightning damage to forests.] Dansk
Sko\'forenings Tidsskr. 45 (6) :236-246.
Hawley, Ralph C. 1937. Forest protection. 262 pp. New York: John Wiley and
Sons, Inc.
147
ALAN R. TAYLOR
Hetrick, L. A. 1942. Some observations of Ips bark beetle attack on pine trees. J.
Econ. Entomol. 35 (2) : 181-183.
Hinds, Thomas E., and Frank G. Hawksworth. 1966. Indicators and associated decay
of Engelmann spruce in Colorado. V.S.D.A. Forest Servo Res. Pap. RM-25,
15 pp., illus.
Hopkins, A. D. 1909. Practical infonnation on the scolytid beetles of North American
forests. I. Bark beetles of the genus Dendroctonus. V.s. Bur. Entomol. Bull.
83, 169 pp., illus.
Jackson, L. W. R. 1940. Lightning injury of black locust seedlings. Phytopathology
30: 183-184.
Johnson, Philip C. 1966a. Some causes of natural tree mortality in old-growth
ponderosa pine stands in western l\lontana. C.5.D.A. Forest Serv. Res. Note
INT-51, 4 pp.
- - - . 1966b. Attractiveness of lightning-struck ponderosa pine trees to Dendroctonus brevico'l1lis (Coleoptera: Scolytidae). Ann. Entomol. Soc. Amer.
59(3) :615.
Kiil, A. D., and D. G. Fraser. 1962. Lightning as a cause of forest fires. Timber
of Can. 1: 30-33.
Komarek, E. V., Sr. 1964. The natural history of lightning. Third Annu. Tall
Timbers Fire Ecol. Conf. Proc., pp. 139-186.
- - - . 1968. The nature of lightning fires. Calif. Tall Timbers Fire Ecol. Conf.
Proc., pp. 5-41.
Kourtz, P. 1967. Lightning behaviour and lightning fires in Canadian forests. Can.
Dep. Forest. and Rural Develop., Dep. Pub. 11 79, 33 pp., illus.
LaRue, Carl D. 1922. Lightning injury to Hevea br.lsiliensis. Phytopathology 12:
386-389, illus.
Lindh, C. Otto. 1949. Ponderosa pine in the southwest. Pp. 347-48, in: Trees, Yearbook of Agr., V.S.o.A. Forest Serv.
Loeb, Leonard B. 1966. The mechanisms of stepped and dart leaders in cloud-toground lightning strokes. J. Geophys. Res. 71 (20) :4711-4721.
McEachron, Karl Boyer. 1940. Playing with lightning. 231 pp., illus. N ew York:
Random House.
- - , and J. H. Hagenguth. 1942. Effect of lightning on thin metal surfaces.
Amer. lnst. Elec. Eng. Trans. 61:559-564.
1\1c'\lullen, L. H., and M. D. Atkins. 1962. On the flig-ht and host selection of the
Douglas-fir beetle Dendroctonus pseudotsugae Hopk. (Coleoptera: Scolytidae).
Can. Entomol. 94(12) :1309-1325.
l\lalan, D. J. 1963. Physics of lightning. 176 pp., illus. London: Engl. Univ. Press, Ltd.
Miller, J. 1\1., and F. P. Keen. 1960. Biology and control of the western pine
beetle. V.S.D.A. Forest Servo Misc. Pub. 800, 381 pp., illus.
l\linko, G. 1966. Lightning in Radiata pine stands in northeastern Victoria. Australian Forest. 30(4) :257-267.
1\ I orris, William G. 1934. Lightning storms and fires on the National Forests of
Oregon and Washington. V.S.D.A. Forest Sen-., Pacific Xorthwest Forest
and Range Exp. Sta., 26 pp., illus.
- - - . 1948. Lightning fire discovery time on Kational Forests in Oregon and
Washington. Fire Control Notes 9 (4): 1-5.
Murray, J. S. 1958. Lightning damage to trees. Scot. Forest. 12(2) :70-71.
Xelson. J. C. 1958. Dying of mature eastern hemlock in Cook Forest, Pennsylvania.
J. Forest. 56(5) :344-347.
New Zealand Forest Service. 1954. Lightning and deaths among Radiata pine.
Annu. Rep. Dir. Forest. 1953/1954,33 pp.
148
LIGHTNING EFFECTS ON THE FOREST
Norinder, H., E. Knudsen, and B. Vollmer. 1958. Multiple strokes in lightning
channels. Pp. 525-542, in: Recent Advances in Atmospheric Electricity.
Atmos. Elec. Proc., Second Conf., Portsmouth, N. H. New York: Pergamon
Press.
Peace, T. R. 1940. An interesting case of lightning damage to a group of trees. Quart.
J. Forest. 34(2) :61-63.
- - - . 1962. Pathology of trees and shrubs. 753 pp., illus. Oxford: Clarendon Press.
Plummer, Fred G. 1912. Lightning in relation to forest fires. V.S.D.A. Forest Serv.
Bull. 111, 39 pp., illus.
Prueitt, Melvin L. 1963. Excitation temperature of lightning. J. Geophys. Res. 68(3):
803-811.
Reinking, Otto A. 1930. Lightning injury in banana plantations. Phytopathology 28:
224.
Reynolds, R. R. 1940. Lightning as a cause of timber mortality. V.S.D.A. Forest
Serv., Southern Forest Exp. Sta. Notes 31, 4 pp.
St. George, R. A. 1930. Drought-affected and injured trees attractive to bark
beetles. J. Econ. Entomo!' 23 :825-828.
Schmitz, Richard F., and Alan R. Taylor. 1969. An instance of lightning damage
and infestation of ponderosa pines by pine engraver beetle in Montana.
V.s.D.A. Forest Servo Res. Note INT-88, 8 pp., illus.
Schonland, B. F. J. 1950. The flight of thunderbolts. 152 pp., illus. London: Oxford
V niv. Press.
Sharples, A. 1933. Lightning storms and their significance in relation to diseases of
(1) Cocos nucifera and (2) Hevea brasiliensis. Ann. App!. BioI. 20(1) :1-21.
Shipley, J. F. 1946. Lightning and trees. Weather 1 (7) :206-210.
Show, S. B., and E. I. Kotok. 1923. The occurrence of lightning storms in relation
to forest fires in California. Monthly Weather Rev. 51(4):175-180.
Stevens, A. F. 1921. Lightning explodes tree and digs trenches. Monthly Weather
Rev. 49(4) :241-242.
Stevens, H. E. 1918. Lightning injury to citrus trees in Florida. Phytopathology
8(6) :283-285.
Stevens, Neil E. 1916. Recovery of a chestnut tree from a lightning stroke. Phytopathology 6(2) :204-206.
Stone, George E. 1914. Electrical injuries to trees. Mass. Agr. Exp. Sta. Bull. 156,
19 pp., illus.
Taylor, Alan R. 1964a. Lightning damage to forest trees in Montana. Weatherwise
17(2) :61-65.
- - - . 1964b. Lightning damage to Douglas-fir trees. Fire Control Notes 25 (1):
fr-7, illus.
- - - . 1965. Diameter of lightning as indicated by tree scars. J. Geophys. Res.
70(22) :5693-95.
---,. 1969. Tree-bole ignition in superimposed lightning scars. V.S.D.A. Forest
Serv. Res. Note INT-90, 4 pp., illus.
Thatcher, Robert C. 1960. Bark beetles affecting southern pines: a review of current
knowledge. V.S.D.A. Forest Serv. Southern Forest Exp. Sta. Occas. Pap. 180,
25 pp.
Trousdell, K. B. 1955. ,Loblolly pine seed-tree mortality. V.S.D.A. Forest Serv.
Southern Forest Exp. Sta. Pap. 61, 11 pp.
Vman, Martin A. 1964. The peak temperature of lightning. J. Atmos. Terrest. Phys.
26: 123-128.
- - - . 1966. Quantitative lightning spectroscopy. IEEE Spectrum 7: 102-110.
V.S. Department of Agriculture, Forest Service. 1962. Report of the Chief of the
Forest Service, 1961.47 pp., illus.
149
ALAN R. TAYLOR
u.s. Department of Commerce, ESSA. 1966. Lightning. 6 pp., illus.
Vanderlinden, E. 1907. Etude sur les Foudroiements d'arbres constates en Belgique
pendant les Annees 1884-1906. [The study of lightning strikes on tree~ observed
in Belgium in the years 1884-1906.] 79 pp. Bruxelles: L'Obser. Roy. de Belg.
Viemeister, Peter E. 1961. The lightning book. 316 pp., illus. New York: Doubleday and Co., Inc.
Vogl, Richard J. 1968. Fire adaptations of some southern California plants. Pp. 79110, in: Calif. Tall Timbers Fire Ecol. Conf. Proc.
Wadsworth, F. H. 1943. Growth and mortality in a virgin stand of ponderosa pine
compared with a cutover stand. U.S.D.A. Forest Servo Southwestern Forest
and Range Exp. Sta. Res. Rep. 5, 16 pp.
Weir, J. R. 1929. Annual report of pathologist. In: Annu. Rep. 1928, Rubber Res.
Inst. of ;\lalaya, 127 pp., illus.
Zhivlyuk, Yu. N., and S. L. Mandel'shtam. 1961. On the temperature of lightning
and the force of thunder. Soviet Phys. JETP 13 (2) :338-340.
150