The recent ice storm caused a lot of damage across the Willamette Valley and tested the strength of every tree species. It left many of us with a mess and asking what we should do with it.
To answer some of those questions, Nicole Ahr of the Clackamas Soil & Water Conservation District asked arborist Brian French, an expert in tree care and management who has 23 years of experience working in the county. He has been busy helping residents throughout the Willamette Valley after this storm.
• What do I look for?
If you think you may need to remove a tree, or feel a tree may be unsafe, cordon off the area, keep people out, and get professional help to assess the situation. Look for an arborist with International Society of Arboriculture (ISA) Tree Risk Assessor Certification. Also, check that the arborist is insured.
Here are signs that your tree may be in trouble. Is the tree leaning more than usual? Are there breaks in the tree, broken branches, cracks, or splits? Is it near a target (something of value like a person, a building, or a valuable object)? Prioritize the targets. Can they be moved? For example, can a car be moved out of the way to deal with the tree? Is there a path that people use under a questionable tree? If so, block the pathway. Maybe there are targets that cannot be moved or avoided, like a tree with a large broken branch hanging over a house. An arborist can provide a professional assessment of a tree where there is a "target" or risk.
• Should it stay or should it go?
When a tree is damaged, it can be hard to assess the tree objectively because there is often an emotional response to the loss of a tree. An arborist can provide an objective assessment of the tree damage and help you move forward. For example, you may have a tree that has lost 50% of its upper crown (top) that now looks messy and unstable.
Part of an objective assessment, however, may recognize that the tree no longer must support all that weight. From that perspective, some damaged trees may be assessed as less likely to fail now than they were before they were damaged. Sometimes all that is needed to fix a tree hazard is to have an arborist remove a few hanging branches and the tree can be left standing.
• Tree wounds and what to do with all of the wood?
Trees are not able to heal like people. Instead, they must seal off areas that are injured. In this process, called tree compartmentalization, the damaged parts of the tree build walls and chemically blocks the area to slow or protect the tree from disease and decay. Do not attempt to apply chemical treatments to damaged trees as it can cause more damage to the tree.
Where trees have failed, you may find yourself wondering what to do with all the wood. For some tree species, like Oregon white oaks, it can be worth contacting a custom mill to determine marketability. To find Oregon contacts for wood processing, try buildlocalalliance.org.
• Need a replacement tree?
Those of you who have lost trees may be wondering what to plant next. French recommends that you consider a native tree species, where possible, that will fit the specific needs of your site. Select a tree whose requirements match your location. Think about soil moisture, sunlight, and space requirements.
When selecting a tree to plant in an urban area, the size and growth form of a tree will be important to avoid impacts on power lines and neighboring properties. For some helpful information on native trees species found in this area and the types of conditions they grow in, you can view a list at portlandoregon.gov/citycode/article/322280.
• The balance between safety and wildlife habitat
When making decisions about trees, safety comes first. Habitat comes second and anything in between those two is worth reconsidering. Aesthetics, or how a tree looks, are not important for habitat value. A damaged tree may no longer look as appealing as it once was, but the habitat value is still there. Newly exposed breaks and cavities can provide nesting and roosting sites for native raptors, woodpeckers, and mammals. Some of these species will provide natural rodent and insect control for your property.
Special consideration should be given to the Oregon white oak habitats that are already in rapid decline in the Willamette Valley. These trees are uniquely adapted to the Valley and many of the remaining mature white oaks are hundreds of years old. They have been through numerous storm events, are resistant to drought, and are fire adaptable. They also provide habitat for over 200 species, including deer, birds, insects and microscopic fungi.
French says if we lose our white oaks, we lose our ability to be awed by the magnificence of some of our oldest trees. We lose the last of a declining and unique habitat in the Valley that defines the people and the species in it.
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