Tree Carnage
The aftermath of the ice storms in winter 2000 was devastating. Several thousand to a million trees were destroyed or received damage in some degree. I became interested in how ice could cause such carnage.
Prior to investigating the actual
forest sites, I establish a graphic chart describing seven different degrees of tree damage and drew an example of
each by hand. Later, a team of colleagues and I visited four forest areas within
the general circumference of the damaged region from south-central to
south-eastern Oklahoma.
Once we located an area of high
damage concentration we began to document the DBH ( diameter at breast height )
and the degree of damage of each tree affected. The data collected from each
tree affected. The data collected from each tree was entered n a data sheet as
the tree was studied. After data collection was completed, the numbers were
calculated to show percentages and patterns in tree damage. In general, the
hardwood trees received more of the major damage and softwood trees received
most of the minor damage. The damage of the trees may vary depending on root
structure, body structure of the tree, tree density, or the location in which
the tree was sited.
Several thousand trees were
left damaged as a result of the winter 2000 ice storms that swept the state of
Oklahoma (1). The majority of the damage can be found in south-eastern and south-central
Oklahoma (figure 1). The areas chosen for sampling include a post oak – black
jack forest in Rough Canyon, Robber’s State Cave Park. An upland post oak/black
jack forest located approximately two miles north of Calvin Oklahoma, a
hardwood forest in Sulphur, Oklahoma and a pecan forest in Stratford, Oklahoma.
The objective of this project was to
survey damages left by ice per tree species and identify a pattern in damage
degree among each individual species. The second objective was to compare the
damage of each forest selected with the other forests. The third objective was
to compare the damage received by hardwood trees with the damage received by
softwood trees. The forests were chosen at random within the general
circumference of the ice damage.
The four forests varied in trees species, allowing for a greater spectrum of results. Only trees showing signs of damage were sampled. The Rough Canyon forest in Robber’s Cave State Park is a pine-oak forest. The forest in Sulphur is a hardwood forest located on the west end of the Chickasaw National Recreational Area. We studied an upland post oak – black jack forest in Calvin. The Stratford forest is bottomland forest composed primarily of pecan trees.
When documenting a damaged tree, the
DBH was measured in centimeters using a hand ruler. The data was logged in the
record book and the tree damaged was assessed using the pre-set damage degree
chart and entered into the data sheet (figure 2). Identification of trees was
confirmed using E. Little (2).
We encountered 14 tree species in
all (figure3)(figure 4). Five species with damage were indentified and
documented in Rough Canyon. These
species were Carya texana (Black
Hickery), Juniperus virginiana (
Eastern Red Cedar), Pinus echinata
(Short-Leafed Pine), Quercus marilandica
(Black Jack Oak), Quercus stellata
(Post Oak). Carya texana trees in
Robber’s Cave State Park had eight trees studied, two of which were of second
degree damage, one of the third degree damage, and five of the sixth degree
damage. Juniperus virginana in this
forest had two trees documented one in the fifth degree damage and one in the
sixth degree damage. Pinus echinata
had thirteen damaged trees in the second degree of damage, sixteen trees in the
third degree of damage, twelve in the fourth degree of damage, forty-four trees
in the sixth degree damage and forty-six trees in the seventh degree of damage.
Quercus stellata of this forest had
two trees in the third degree of damage and one in the fourth degree of damage.
Quercus marilandica had seven trees
in the second degree of damage and seven in the third degree of damage, three
trees in the sixth degree of damage and one in the seventh degree of damage
(figure 5). The
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Sulphur
forest had ten different species of damaged trees. These included Ulmus
americana ( American Elm), Ulmus alata (Winged Elm), Acer negundo (Box Elder), Carya texana (Black Hickery), Celtis (Hackberry), Quercus shumardii ( Shumard Oak), Fraxinus (Ash), Juniperus
virginiana , Maclura pomifera ( Osage Orange) and Platinus occidentalis. Juniperus virginiana in this forest had nine
damaged trees. Of those trees five had second degree damage, three were of
third degree damage and one was of seventh degree damage. Ulmus americana had eight documentable trees. One showed secondary
damages and the remaining seven showed third degree of damage. Ulmus alata of this forest had three
damaged trees. One secondary damage and two third degree damage. Acer negundo showed only two damaged
trees both of which had third degree damage. Celtis sp. had seven damaged trees in the forest. Second and third
degrees both had three trees and fourth degree had only one tree. Quercus shumardii had six damaged trees.
One was of first damage degree, three were of third damage degree, fourth and
fifth damage degree each had one entry. Fraxinus
sp. had three damaged trees: one second degree, one third degree and one
fourth degree (figure 6). Three species of trees with damage were documented in
the Calvin forest including Q. stellata,
Q. marilandica and Juniperus
virginiana (figure 7). There were also only three species of damaged trees
in the Stratford forest. These species include Q. stellata, Carya illinoensis and Q. marilandica. Q. stellata
had one tree in the second degree of damage. Carya illinoensis had two trees in the second degree of damage,
three trees in the third degree of damage, four trees in the fourth degree of
damage and one tree in the fifth degree of damage. Q. marilandica of this
forest only had one damaged tree which was of the second damage degree (figure
8).
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In comparison, approximately 24% of
he damaged hardwood trees received major damages (figure 9). Minor damage is
anything with categories 1, 2, or 3 and major damage is anything higher than
the third degree of damage. Of the softwood trees 74% received major damages
(figure 10). Robber’s Cave State Park forest was a pine-oak forest with 70%
major damage. 59% of the upland post oak –blackjack forest of Calvin received
major damage. The bottomland pecan forest received only 8% major damage.
The results of this research show that the hardwood trees have less damage than softwood trees. The trees that received the majority of the major damage were thepines and junipers (figure 3), while the hardwood trees received less damage. This is possibly due to different root structure, and the differences in density of wood in softwoods and hardwoods. A second possible reason for more damage in softwoods versus hardwoods is location due to the more severe damage in the south-east than in the south-central part of Oklahoma. The two south-central forests received approximately the same amount of major damage, while the south-eastern forest (Robber’s Cave and Calvin) also compared he same. The damage may read similar due to the close range in distance between the forests.
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Figure
1-(top) – Map of Oklahoma ; highlighted areas are circumference of damage
Figure
2 (bottom)– Damage degree chart used in assessing damages of trees


Figure 3 – (bar
graph) Overall comparison of tree
damage by species
Figure 4 – (pie graph) Overall comparison of damage degrees


Figure 5 – (top) – Comparison of damage degrees in
Rough Canyon at Robber’s Cave
Figure 6 – (bottom) –Comparison of damage degrees at
Sulphur forest


Figure 7-(top) – Comparison of damage degrees in
Calvin forest
Figure 8-(bottom)– Comparison of damage degrees in
Stratford forest

Figure 9 –(top) –
Comparison of all hardwood trees studied
Figure 10-(bottom) –Comparison of all softwood trees
studied

January 8, 2001
1) Daily Oklahoman Newspaper Article and Map
by Bryan Painter
2) Little, E.L. Jr. Forest
Trees of Oklahoma. Oklahoma Forestry Services State Dept. of
Agriculture.(1991).205 pp.
I would like to thank Dr.
Smith, Paula Tolbert, Jeremy Rummel, John Story, Scott
Shamrock,
Brian Hathaway, Richard Conley, and Mitch Arteberry for their assistance in
my
data collections and computation.