|Polk County Enterprise - Local News
Stories Added - October 2009
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Engraver beetles feasting on stressed pine trees
Polk County Enterprise - October 2009
BY CHARLES K. FRANKLIN
LIVINGSTON — When it rains it pours, but when it doesn’t the damage can be just as severe. Polk County experienced one of the worst droughts on record this summer and the shortage of water may have left many pine trees vulnerable to an attack by pine beetles. The tell-tale sign of an infestation is red pine needles, but by then the damage has been done and the beetle larvae have grown to adulthood and moved on to the next tree. This year’s infestation was severe for local residents when compared to other years but fortunately the damage the little pests caused was spotty. Timber companies battle these bugs annually and have preventive measures in place to limit the damage it can do. “This year has been exceptionally bad,” U.S. Forest Service District Forester Steven Cooke said.
“The ones that notice it, and are really concerned about it, have small acreage lots.” The Southern Pine Beetle is most often the root of the problem but it caused no significant damage this year. Instead, its cousin the Ips Engraver Beetle was the main culprit, according to Cooke. The little critters, no bigger than a lowercase “i” on this page, attack a tree that has been weakened in some way, usually by a catastrophic natural event. “The only good thing is that it only attacks stressed out trees,” Cooke said. “They can be stressed due to drought, or actual damage to that tree from the hurricane. Hurricane Ike stressed out a lot of trees. Even the high temperatures we saw at the end of August and September put stress on the trees and that timeframe coincides with the life-cycle of the Ips beetle and it compounds the problem.
Even though you don’t see any physical signs on the tree it could still be stressed out.” There were quite a few stressed trees this year, though, after the local forests were hit with a doublewhammy. With Hurricane Ike blowing through last September, followed by the significant drought the area experienced during the summer, many trees were suffering but remained standing and vulnerable to infestation. “They attack in numbers, thousands at once,” Cooke said. “You’ll notice a discoloration in the needles and within a week the whole tree may be red.” By then it’s too late to do anything but lament the loss of the tree. The beetles have laid their eggs, the eggs have matured to adulthood and the new crop of adult beetles have moved on to another tree to begin the cycle again.
“They’re already gone by the time the tree is red and dead,” Cooke said. But there are other signs of the infestation and if the tree can be removed before the larvae have matured, neighboring trees might be saved. The most obvious sign to look for is a red-colored sawdust around the base of the tree. Another sign is a reddish-white or yellowish-white pitch (resin) tube protruding from a piece of bark. The pitch tube will be on the bark itself as opposed to the crevice between two pieces of bark where sap typically runs. But in very dry weather there may be no pitch-tube at all, just the telltale reddish-colored sawdust in the bark crevices and around the base of the tree.
The reddish color in the pitchtube, and in the sawdust it ejects from the tree as it bores into it, is caused by a fungus on the beetle itself. Some experts believe the fungus may play a part in the death of the tree as well. Pine beetles will bore through the bark and create a gallery behind it where the larvae are stored. Each chamber will hold a larva until it grows to adulthood and escapes the tree in search of another. Young larvae will bore inwards toward the soft pulp, depositing fungus that damages the circulation of the tree. If an infestation is suspected it can be verified by pulling a piece of bark away. The gallery will be prominent and clearly visible. The galleries will most often be in the shape of a “Y” or an “H” with the various chambers branching off of the main tunnels. Dead branches are not an indicator of a beetle infestation, according to the Texas Forest Service website.
A tree may lose a branch from one year to the next but remain healthy. Preventing infestation The Texas A&M AgriLife Extension program recommends watering trees during times of drought to prevent an infestation. “If you have a few really nice pine trees in your yard it would be a good idea to water,” Cooke said. Livingston resident Susan Tullos believes a lack of water in her yard was responsible for the loss of 33 pine trees, and counting, on her property. All she has to do is look to her neighbor’s yard where a sprinkler system has been installed. That yard lost only one tree at the rear of the property, out of range of the sprinkler heads. “I think that’s proof-positive that a well-watered yard could have prevented this.” Tullos said. She and her husband Jerry had considered installing a sprinkler system in years past but opted against it as their property is partially in a designated wetland. Tullos said they will reconsider installing a sprinkler system. She said the cost to remove the dying trees is about the same as what it would cost for a sprinkler system for her yard but it would offer a peace of mind money cannot buy. At least some of the cost for removing the dying trees may be reclaimed on annual income taxes as a casualty-loss due to Hurricane Ike.
“There are special clauses in the law for trees and the damage caused by hurricanes,” CPA Loretta Black said. “They need to check with their CPA or tax advisor because there are ways it can be deducted.” “There are also special tax deductions allowed in cases of droughts,” Black said. “As long as it has been formally declared.” Other areas in the nation: Colorado and its neighboring states are battling one of the worst infestations of Mountain Pine Beetle on record. Experts expect nearly all of the state’s Lodgepole Pine trees over five inches in diameter will succumb to the onslaught of the Mountain Pine Beetle. One of the contributing factors is the age of the trees. Nearly all of the trees are roughly the same age at 80 to 90 years, according to the U.S. Forest Service website. As a preventive measure the forest service in Colorado will initiate an effort to stagger the ages of the trees as they grow back so whole forests will not be susceptible in the future. East Texas foresters have long practiced ways to mitigate the effect of the Southern Pine Beetle and its wood-boring cousins. One method, selective harvesting, plucks a few of the trees from a stand while leaving many others to continue growing. Gone are the days of massive clear cutting and replanting.
By initiating a selective harvest, foresters use the remaining trees to regenerate the forest naturally and to offer protection from high winds as the young trees mature. The age disparity among the trees creates a healthier forest overall, according to information on the US Forest Service website. Former Illinois Gov. Rod Blagojevich Proclaimed April 17, 2008, to be Asian Longhorned Beetle Eradication Day when it was found an infestation of Asian Longhorned Beetles was responsible for the destruction of more than 1,500 trees in northeastern Illinois. The beetles had traveled all the way from China in the wood of several packing crates. The eradication efforts in Illinois were successful at containing the spread of those beetles, according to a U.S. Forest Service website. Current Situation Locally, the worst may be over for this year, but the county is not completely out of the woods yet. Infested trees continue to be found each day. “Right now we are starting to see the numbers of these beetle attacks die down,” Cooke said.
“But they’ll be back next year I’m sure.” Although mother nature cannot be controlled, there are some things homeowners can do to mitigate unnecessary stress to trees. • Keep heavy equipment away from the base of a tree to prevent the dirt from being compacted • If you have a thick grove of young trees, thin them out so the remaining trees have room to spread their branches • Avoid chaining a dog to a tree as the chain can have a girdling effect that chokes the tree • Apply pesticides to the outside of the tree (May have to hire a professional for taller trees) For more information on the Ips Engraver Beetle and what can be done to prevent the spread, see the Texas Forest Service website: texasforestservice.tamu.edu. Click on Insects and Diseases in the left-hand column then click on Insects again in the left-hand column under Pest Management. Scroll down to the section on Pine Engraver Beetle (Ips Beetles).