COLUMBIA – The 2012 drought has stressed hardwoods in Missouri forests and affected the production of "mast crops" that deer and other wildlife depend on for food.
Red and white oaks in the state have been particularly hard-hit by the lack of rain, according to state foresters, and a lean mast crop stands to affect deer hunters this fall.
"The last couple of years we've had really good acorn crops, so the deer spread out a lot over the landscape, and they don't have to move around as much," Jason Sumners, a deer biologist at the Missouri Department of Conservation, said.
There are more than 300 plants in Missouri that deer feed on, Sumners said, and fewer wild nuts during the fall and winter tend to push deer out of the woods in search of agricultural crops and other food sources.
"Having a poor acorn crop will push the deer into open areas where they are more visible," Sumners said.
Jim Licklider, an urban forestry intern at the Missouri Department of Conservation, said trees often produce extra mast when they're under duress.
"A lot of the time when trees are stressed, they can put out a stress crop," Licklider said. "If they sense that they’re dying, they’ll produce extra mast, but I haven’t even seen that this year because it’s been so dry.”
Licklider said that plentiful rainfall in Missouri between 2008 and 2010 "lulled trees into a false sense of security by decreasing their drought tolerance," which is one reason that dry conditions over the past two summers have been damaging.
In addition to diminishing the mast crop, preventing new root growth and the expansion of hardwoods, drought conditions also compromise the immunity of older trees from diseases and infestations.
“Some of the older trees are showing stress, and we have to water those as much as we can, especially the older ones that were planted near construction sites, which are more vulnerable to drought stress," said Brett O’Brien, natural resource supervisor for Columbia's Department of Parks and Recreation.
Consequently, the department has focused its attention on expanding watering efforts throughout the city.
“The cost is mostly in the labor because we’ve had to spread out and use water trucks," O’Brien said. “On the flip side, we’re not mowing as much.”
Urban trees, unlike those that grow in floodplains or forests, can be more sensitive to drought and secondary infections because of the limited space that their roots have to expand. The urban "heat island" effect also increases evaporation from leaves, Licklider said.
Thorough and regular soaking can save stressed hardwoods. Forestry experts recommend that property owners not preemptively cut down sullen-looking trees simply because of withering leaves or bare branches because some trees that seem dead may have instead gone into early dormancy.
City arborist Chad Herwald said one way to check on the health of a tree is by testing the pliability of its finer branches.
"If you take a branch that's an eighth-of-an-inch in diameter, bend it and it breaks, then it's dead," he said. "Otherwise it's most likely gone into dormancy."
Rich Blatz, a program supervisor in the Missouri Department of Conservation's forestry division, said it'll be spring before the impact of the drought begins to be known. He often advises homeowners to hold off until spring before cutting down affected trees unless they’re a hazard.
"Trees are extremely resilient," he said. "They can take a lot of damage and come back the same as they were before."
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