You’ve been granted free access to this subscribers only article.
Drought leaves trees susceptible
COLLEGE STATION -- The drought of 2011 appears to be fading as far as rainfall totals go, but less obvious impacts may continue for years as weakened trees fall victim to pests and disease, tree experts note in a Texas A&M Extension Service press release.
“One thing that most people don’t realize is that this drought is going to have an impact on the trees that were damaged in 2011 for probably five to seven years from now,” said Dr. David Appel, Texas A&M AgriLife Extension Service plant pathologist. “And that’s assuming that we get normal rainfall. If we have another drought, that could set them back even further.”
Appel, who specializes in trees, said certain diseases are going to be on the increase because of the drought.
The Texas A&M Forest Service estimates 301 million rural trees and 5.6 million urban trees died from the 2011 drought and its impact.
“The visual manifestation of the drought includes limb dieback, the crown is going to be asymmetric or lopsided, growth is going to be reduced, and there will be smaller, more yellow leaves,” Appel said of stressed trees. “All of this is a sign that the trees were depleted of their carbohydrate reserves during the drought, and they just aren’t able to carry on the normal growth that they would in normal years.”
He said tree owners may also see infection by certain kinds of fungi, which can be dangerous.
Knowing whether a tree is dead or dying can be hard to tell, he noted, and one may want to wait until next spring to examine leaves and overall health or call a tree expert before cutting.
However, he said there are a few simple things one can do to test tree health.
“Do a twig test. Take the twigs and bend them. If the twig is pliable, then you know it’s still alive and it’s just going through normal senescence,” Appel said. “However, if the twig breaks then you can be sure that that twig is dead and those are the kinds of branches that need to come out of the tree.”
One disease having an impact currently is Hypoxylon canker, he said.
“You might see this on a water oak where the bark sloughs off and it has this light gray coating just underneath the outer bark,” Appel explained. “If that’s coming out, then the tree is dead, and it definitely should come down. Once this fungus starts growing into the wood, it greatly reduces the structural integrity and the tree can become dangerous.”
He said this is also showing up on sycamore -- with large black marks on the trunk -- and some other types of trees.
“Generally we recommend to get an expert up there not only because they know what to look for and take out, but always there is also the safety concern of having people climb around in their trees without the proper equipment,” he added.
Otherwise, Appel suggested, continue to watch trees until next spring, and the next spring and the next spring, because there isn’t a lot that can be done for trees in this condition.
“Research has shown that the carbohydrate reserves in these trees are still depleted to five, six, seven years after the drought occurred, even if we get good weather and rain,” he said. “So it takes awhile for the trees to come back before they’re going to be able to resist all the insects and fungi that normally do them no harm and before they’re going to get back to normal growth.”
Your Opinions and Comments
Be the first to comment on this story!
You must be logged in to post a comment.
Agriculture Today Archives
Floresville FFA teams state-bound (April 27, 2016)
Floresville FFA wins in Houston — livestock, judging, tractor restorations (April 27, 2016)
Hail damage may reduce harvest (April 27, 2016)
Karnes City Auction sale (April 27, 2016)
Land Stewardship produces a healthy Texas (April 27, 2016)
Livestock Market Reports (April 27, 2016)
Pesticide class set for May 16 (April 27, 2016)
TDA Market Recap (April 27, 2016)
Texas Hay Report (April 27, 2016)
Ag program for military (April 20, 2016)
Benefit team roping in Jourdanton (April 20, 2016)
Bird feeding options (April 20, 2016)
Catfish management plan released (April 20, 2016)
County 4-H’ers place in Houston (April 20, 2016)
Guada-Coma Chapter news (April 20, 2016)
Livestock Market Reports (April 20, 2016)
Regional conservation partnership (April 20, 2016)
TDA Market Recap (April 20, 2016)
Texas Hay Report (April 20, 2016)
Youth Range Workshop (April 20, 2016)
Always follow label instructions (April 13, 2016)
Chemical collection is May 11 (April 13, 2016)
Livestock Market Reports (April 13, 2016)
Nixon-Smiley show produces champions (April 13, 2016)
TDA Market Recap (April 13, 2016)
Texas Hay Report (April 13, 2016)
East Central’s Patterson, Kempen, and poultry team win at SA show (April 6, 2016)
Livestock Market Reports (April 6, 2016)
Pruning without painting? (April 6, 2016)
TDA Market Recap (April 6, 2016)
Texas Hay Report (April 6, 2016)
Tree grafting, pruning workshop (April 6, 2016)
Wilson County Spring Educational Program (April 6, 2016)
April 2016 Gardening Calendar (April 1, 2016)