Released Nov. 26, 2007
MANHATTAN, Kan.--The experts’ tree-pruning rules allow for one big exception: Any time is the best time of year to remove diseased, damaged or dead branches.
Late fall can be an especially prudent choice, however, said Charles Barden, forester with Kansas State University Research and Extension. Outdoor temperatures are still likely to be above 20 degrees. When the weather’s colder than that, the act of pruning itself can cause tree injury.
The timing also gets rid of weak branches before they can become a deadly missile in a wintertime ice storm.
“A combination of heavy ice and strong winds can easily turn a damaged limb into a ‘widow-maker.’ At the same time, the mix of ice and wind will test every weak joint in the tree,” Barden said.
Mature limbs often weigh hundreds to thousands of pounds. But, an accumulation of ice can increase that by 30 times or more, he warned. Plummeting to the ground just adds to the weight’s force.
“A small, icy branch can hurtle down like a frozen spear,” Barden added. “If it hits with its pointed end first, a twig can go right through a roof.”
Compared to deliberately pruned limbs, weather-broken branches are much more likely to cause collateral tree damage, too, he said. A big break can leave split wood behind or peel away great swaths of bark and internal wood from the trunk. Once free, the limb also can break others and/or damage any part of any tree it hits on the way down.
“Of course, taking out power lines is certainly no challenge for an ice-damaged tree. Any nearby building will be at risk, as will any passing car, pet or person,” Barden said.
Each tree owner has to make the call on whether to prune out problem branches or hire a pro to do the job. To help owners in making that decision, however, Barden offered guidelines he’s picked up from foresters and long-time arborists:
- If you wonder whether you have the experience, knowledge or assurance level to do the job safely, you probably don’t. Find a reputable tree care service and ask for a certified arborist.
- As a rule of thumb, if a branch is less than two inches wide, go ahead. If it’s two to four inches thick, think twice. If it’s more than four inches across, get experienced help or be very sure of what you’re doing.
- Cutting or pruning above ground is extremely dangerous without firm footing in a lift or a comfortable, secure anchor to the tree. Rather than trying to work from a ladder, hire a professional.
- Never work near power lines. Call the electric company, which will have arborists on staff.
- If you can’t find and review your chainsaw manual, seriously consider hiring someone else to do the work. Experience helps – a lot – and that includes the insights gained while operating a particular saw. Nonetheless, the great majority of chainsaw injuries each year happen to experienced operators, using familiar machines.
Barden also advises tree owners to learn the recommended guidelines for pruning. If nothing else, owners should know when and why to prune a tree. And, they should recognize the steps involved in doing a good (and safe) job – whether doing their own pruning or overseeing someone else.
County and district K-State Research and Extension offices can provide that kind of information, he said. The U.S. Department of Agriculture’s Forest Service has a short manual called “How to Prune Trees” on the Web at http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun001.htm. K-State Research and Extension’s “All About Pruning” (C-550) covers what to do with both deciduous and evergreen trees and shrubs. It is available online at http://www.oznet.ksu.edu/library/hort2/c550.pdf.
“You’ll find that the general recommendation is to prune healthy trees and branches later in winter, during the first three months of the new year,” Barden said. “That timing greatly reduces the odds for excessive-looking sap loss. Besides, the unhealed wounds and the chemical scents that they emit won’t be able to attract the insects that help spread such diseases as Dutch elm and oak wilt.”
Species, Site and Care Set the Odds for Plains Trees’ Weather Damage
MANHATTAN, Kan. – Just getting through a winter in good shape can be a real challenge for High Plains trees, said Charles Barden, forester with Kansas State University Research and Extension.
“One of the real challenges of landscaping here is to choose and care for trees in ways that lower the odds they’ll end up as weather victims,” Barden said.
Homeowners can have problems even if they only plant trees suited for their growing zone.
“For one thing, the fastest growing trees can seem very appealing, but they’re rarely tough,” Barden explained. “For example, Chinese and Siberian elms, poplars, silver maples, birches, Russian olives and willows are all predictable victims. It’s part of their nature to have brittle, easily damaged wood. And, if they don’t lose any damaged wood quickly, it can foster rot and decay in the tree. ”
Most of the High Plains, Midwest and Northeast are in the U.S. “ice-loading” district ranked as being most at risk for ice storms, he said. The district’s weather patterns are the most likely to develop conditions that result in icy precipitation. Beyond that, its storms can deposit ice layers of one-half inch or more (the most damaging category).
“Plains ice storms aren’t an every-winter occurrence. When they do arrive, however, they tend to be memorable – like the 2002 storm that closed down the greater Kansas City area ... the 2005 storm that wasted so many trees in and around Wichita ... and, of course, the ice earlier this year across much of western Kansas,” Barden said.
For trees, a little ice is an amazingly heavy burden, he said. Branches already weakened or killed by damage, insects or disease often fall under the load.
“That in itself can lead to all kinds of additional problems. So, getting rid of those branches before winter can be important to keeping the rest of a tree healthy,” the forester said.
Ice and wind together can be a much more dangerous combination, however – literally snapping off huge branches and splitting apart trees.
The odds that wind and ice will combine are fairly good, too. Plains winds are a year-round peril.
“Chicago may call itself the Windy City, but Dodge City usually comes in as No. 1 among the communities on the ‘windiest’ list that the National Climatic Data Center puts out,” Barden said. “Although their averages aren’t as high, Goodland, Wichita and Concordia also tend to register as being at least twice as windy as Chicago.”
Whether alone or combined with ice, wind is a major reason why High Plains trees tend to do better with some “training.”
“I usually recommend pruning annually for structure, shape and health during a landscape tree’s first ten years of life. Late winter – some time after the first of the year – is a good time for that, unless the trees are spring bloomers,” he said.
For example, if its center of balance remains off, a tree will always be vulnerable to wind damage, Barden pointed out. Trees with rubbing branches or competing leaders will face risks, too.
“The most common victims, though, are probably the branches or leaders that are attached by a V-shaped crotch and have been left to mature that way,” he said.
“When you’re looking at a tree, you need to think of it as being a clock, with the bottom of the trunk at six o’clock and the top of the leader at 12. The strongest branches will be out between two and three o’clock on the right and between nine and ten o’clock on the left. In other words, their crotch will be holding them at about a 90 degree angle from the trunk.”
Removing structurally weak branches not only makes the whole tree stronger but also decreases the surface area and wind resistance that can make trees vulnerable to winter damage, Barden said. It can even help trees with brittle wood.
“The fact is, a heathy, vigorous tree that receives regular care is less likely to become a hazard than one that is ignored,” the forester said. “Prevention is the best solution to tree hazard problems.”
Drought is easy to identify as a High Plains tree stress. Some central U.S. climate experts are saying the area’s long-term weather records indicate that another drought is due ... soon.
“Right now, though, homeowners need to be thinking about the fact that trees should never go into the winter thirsty,” Barden said. “They also should be planning keep watch through the season so they can irrigate once or twice again, if necessary, when the temperature’s above freezing.”
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http://www.oznet.ksu.edu/news/sty/2007/tree_branches112607.htm
Contact: Kathleen Ward, kward@oznet.ksu.edu
Charles Barden, (785) 532-1444 or cbarden@ksu.edu
