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Caution Advised in post-storm care and clean up
Contact Cynthia Orlando, 503-945-7421 or
Paul Ries, 503-945-7391
“They call it stormy Monday" sang the lyrics to an old song, but after The National Weather Service issued flood warnings along the Oregon Coast and in several inland counties including the Portland area, Oregonians are hoping Tuesday won't be just as bad.
Power outages are happening up and down the coast.  Trees are down in many Oregon communities. And after surviving 700 years of storms, just outside of Seaside the nation's largest Sitka spruce succumbed to high winds, snapping in two about 75 feet off the ground.
Once the winds calm down, lights come back on and people have a chance to step outside, many Oregonians will get busy surveying trees around their homes and businesses trying to assess damages and the need for tree care. Usually, following any major storm event, many homeowners are anxious to have tree work completed. However, according to Paul D. Ries, a certified arborist with the Oregon Department of Forestry, "it's quite possible that as many trees will be damaged as a result of clean-up as were directly damaged by the storm."
That’s because many times it’s the improper pruning done to trees by inexperienced homeowners or unqualified tree “experts” that causes the greatest damage. Topping, the practice of removing large branches and tops of trees, actually creates future hazards rather than eliminating them. A previously topped tree is much more likely to break or uproot in a storm than a tree that has a normal branch structure.
“Homeowners should use caution when selecting a tree service company,” warns Ries, who manages the state’s urban and community forestry program. Don’t over-react, and wait for an available certified arborist to prune trees – even if that means waiting longer for service.
Why do some trees remain intact, while others topple over?
It's sometimes hard to predict what will happen to trees in landscapes during storms, but the most common tree hazards occur when trees are unhealthy or stressed. One common reason for a tree to fall is because of some type of root problem. Two of the more common causes are laminated root rot, and armillaria root rot. The first is fairly common and attacks Douglas-fir, hemlock, noble and grand fir throughout the Pacific Northwest. It's hard to detect but easiest to observe - especially with professional help - in the roots of fallen trees.  It's spread by root-to-root contact and can infect other trees nearby.
Armillaria root rot can attack the same tree species, as well as western red cedar, and signs include oozing of sap from the lower trunk, as well as the presence of small, black, stringy growths called "rhisomorphs" around the roots. Roots that have decayed from these diseases may no longer do an adequate job anchoring a tree - especially when high winds are present.
Other causes of trees falling over?  Once soils are saturated with water, trees may be rocked over by wind, and on slopes, trees are susceptible to slippage from debris flows.
Why branches break
Sometimes branches break at the "branch collar" - where the branch attaches to the main trunk. This is a part of normal self-pruning, but it’s often caused by decay that has gone unnoticed by the home or property owner.
A tree's larger limbs can sometimes become weakened by rubbing or past, unrepaired storm damage. These wounds are weak spots that sometimes snap under the pressure of wind.
Large, horizontal limbs sometimes put unreasonable demands on a tree and supporting trunk tissue under the branch gives way in a storm.
Standing trees with damaged branches should be evaluated by a certified arborist before a removal decision is made. A certified arborist is someone who has passed a certification exam administered by the International Society of Arboriculture, the professional society for arborists. The PNW-ISA maintains a list of certified arborists for hire on their website at www.pnwisa.org
An ounce of prevention
The best advice? “Healthy, well cared for trees are the best defense against tree damage when the next storm blows through the state,” adds Ries. Some tips:
  • Have a qualified arborist inspect your trees annually and provide you with a written report;
  • Prune trees correctly when they are young, and regularly thereafter;
  • Don’t allow trees to be topped!
For help with post-storm assessments
Use caution in dealing with the aftermath of the storm. Although Oregon requires tree service companies to register with the state, they are not required to adhere to proper pruning standards or even demonstrate pruning knowledge in order to obtain a license. Hire a company that is bonded and insured. Most reputable companies have business cards, truck signs, and even uniforms that represent a professional level of service. When in doubt ask for references, and take your time to select a reputable company.
Most importantly, avoid hiring anyone who will top a tree.
Certified arborists and information about them can be found in the phone book typically under "Tree Service,” and on the Internet at  www.pnwisa.org, www.oregon.gov/ODF/URBAN_FORESTS/credentials.shtml, and at www.treesaregood.org.
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