Prepare your Trees for Winter
Trees in the street area: If your tree is located within a street right of way, it is regulated by the City of Seattle. Trees that have been planted by the City of Seattle (typically those along arterial streets) are maintained by the City. Trees that have been planted by abutting property owners are the maintenance responsibility of the current abutting property owner. The City Arborist, at (206) 684-TREE (8733), can answer questions about the ownership and maintenance responsibility of your street trees.
Trees on private property: If you have concerns about trees on your private property, the Pacific Northwest Chapter of the International Society of Arboriculture (ISA) certifies professionals to inspect trees for defects and weakness in branches that otherwise may go unnoticed. Large trees are an extremely valuable asset to both the individual property owner and the community. An investment in pruning or inspection can help prevent damage from wind, snow or ice, and help preserve those irreplaceable older trees that add so much to the character and heritage of our city.
Arborists who are affiliated with the ISA are listed in the yellow pages under "Trees", with the ISA logo or "ISA Certified Arborist" logo displayed in their advertisements. If your trees are located within the street right of way, you can request inspection by City of Seattle personnel.
Preventative Maintenance: According to Nolan Rundquist, Arborist for the City of Seattle, strategic pruning to prevent branch failure is a good idea for both the trees and the people who live around them. He knows first hand that the time invested in preventative maintenance is well spent. Trees that are pruned regularly should be more resistant to storm damage as a result of the removal of structurally weak branches, decreased surface area of lateral branches and decreased wind resistance.
Trees that have their canopies covered with ivy or clematis may not be able to withstand the additional wind or snow load caused by the extra leaf area of the vines. Removal of invasive vines is important to the health of your trees.
Trees that have structural defects may incur storm damage from snow, ice or wind. Some defects to look for are:
Dead Wood - dead trees and large dead branches are unpredictable. Dead wood is brittle, and cannot bend in the wind like a living tree or branch. Branches that are already broken off and hanging in the tree should receive prompt attention.
Cracks - A crack is a deep split in the tree, which extends through the bark and into the wood of the tree. Cracks are indicators of potential branch or tree failure.
Decay - a "hollow" tree can be prone to failure, but presence of decay does not necessarily indicate that the tree is hazardous. Trees usually decay from the inside, forming a cavity. At the same time, new wood is added to the outside of the tree as it grows. If the outer shell is sound, the tree may be relatively safe. Evaluating the safety of a decaying tree is best left to a trained arborist.
Root Problems - Trees with damaged roots may blow over in wind storms. Have your tree checked if over half of the roots have been crushed or cut; if the tree is starting to lean and soil is "pushing up" around the base of the tree on the side opposite the lean; or, if decay is present in the buttress roots or base of the tree.
Poor Tree Composition - An example of this would be a tree with a weak branch attachment, a large branch that is out of proportion with the rest of the tree, or a tree that leans excessively. Not all leaning trees are hazardous, but if youíre concerned about the tree, it should be examined by a professional arborist. Weak branch attachments (typically, these are narrow "forks" in the tree) are also best evaluated by a professional arborist.
Prune your trees to remove dead or weakened limbs, starting when they are young. DONíT TOP TREES! Larger trees can benefit from having excess branches thinned from their crowns, which lets wind pass through. You should be able to see into your tree, but not through it!
Keep your trees healthy by caring for them all year long. Proper watering, mulching, fertilizing and pruning will help them be an asset to your property and the community for years to come.
Plant the right tree: When you are planting new trees, select the right tree for your location. To avoid damage from early snow and ice storms, donít choose trees that retain their leaves late into the fall. Donít plant too close to your house, and avoid species that are susceptible to breaking, such as Willows, Box Elders, Poplars, Bradford Pear and Silver Maples. If you are planting within the street right of way, you can obtain a list of approved trees from the City Arboristís office at (206) 684-TREE (8733). City employees can assist you in making the proper selection for your area.
Older trees: If you have a valuable older tree that is unique due to its size, character or rarity, you should consider contacting Plant Amnesty at (206) 783-9813 about their Heritage Tree Program. This program recognizes significant trees with a certificate and plaque, and can even offer legal protection to the tree if it is desired by the owner.
For more information:
City of Seattle Arborist (206) 684-TREE (8733).
For persons with hearing disabilities, TTY (206) 684-4009.
To request this information in alternate formats to accommodate persons with disabilities, call (206) 684-8548.