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
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). 3
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.
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.