Mar. 6 column: The Nov. 17 Windstorm

If you live in the Inland Northwest, you know that we had a horrific windstorm on Nov. 17, 2015. There were peak wind gusts of 71 mph, four people lost their lives, there were power outages everywhere, and an incredible amount of damage left in its wake.

Now that spring is nearly here, homeowners are working on cleaning up the last of the damage and trying to decide which trees would make good replacements for those that were lost. With this in mind, I have written this week’s column to address the aftermath of the windstorm. I also discuss how to choose new trees.

Here is a link to my column in today’s edition of The Spokesman-Review: Reviving the Urban Forest. Even if you didn’t experience any damage in the storm, this article contains extra information. Learn about important considerations for selecting trees in your landscape. There’s also an information box with several links to tree guides and other resources. I hope you’ll find it interesting and helpful! You can also read my column below:

Column:

by Susan Mulvihill

On Nov. 17, 2015, Spokane was hit with a severe windstorm that caused countless trees to topple. Many homeowners are now faced with the task of replacing those trees. They’re probably also wondering if a windstorm of that magnitude will hit again.

Angel Spell has been assessing the damage and often hears that concern.

She is the Urban Forester for the City of Spokane. Spell manages the trees within the city’s parks and other public property, along with trees planted on street rights-of-way.

Tree failure statistics

The Parks and Recreation Department has been compiling statistics of tree failures attributed to the windstorm. The numbers are quite interesting.

“Evergreens were the predominant failures,” she said. “Sixty-five percent were pine trees and 21 percent were spruce. Nine percent were fir trees. The remaining 5 percent were other trees hit by falling pine, spruce or fir trees during the storm.”

Those statistics might imply evergreens are not the tree to plant in windy regions, but that’s not the case at all.

“Neither evergreen nor deciduous trees withstand wind better than the other,” she explained. “In a big wind event like this, the trees that were damaged were more exposed.”

Why some trees were damaged

As Spell visited the parkland throughout the city limits, she observed how the damaged trees were on more exposed sites. If a tree was taller than the surrounding trees, it sustained serious damage. But it goes beyond this.

“A tree’s ability to withstand strong winds isn’t about the root system. It’s more about the soil structure surrounding the roots,” she pointed out.

Which trees easily uprooted? Those planted in sandy or gravelly soils, or those planted above basalt rock where there’s a minimal amount of soil. Even so, Spell made an important recommendation for watering trees planted in lawns.

Tree care advice

“Water those trees more deeply and less frequently than you do your lawn. That will encourage deeper root development,” she advised. “And don’t have the lawn surround your tree. Give it some turf-free space under its canopy. That will provide a visual reminder that there is a difference in what our trees need versus our lawns.”

Spring is an ideal time to plant trees. Many homeowners are likely puzzling over which types of trees would make good replacements. Spell suggests they consider their goals for adding a tree first.

Some might need shade or have a fondness for spring-flowering varieties that add color and beauty. Others want to increase their property value, improve air quality or add privacy and/or screening from traffic noise. And still others would like to attract birds and wildlife.

Choosing the right size of tree

Spell also recommends looking at the surrounding elements that dictate how large a tree to plant:

“Think about how much space you have. Take into account underground and overhead utilities, nearby sidewalks or driveways. And don’t forget other trees that would compete for sun and space,” she suggested.

Street tree resource

Once those items have been addressed, homeowners can take advantage of a special resource. The detailed Approved Street Tree List on the Urban Forestry website has ideal choices.

It includes trees for planting beneath overhead utility lines. Homeowners will find small, medium and large trees that fit within various widths of parking strips and in other settings. The list itemizes each tree’s mature height, light and moisture needs. It also includes fall foliage colors, growth rates, hardiness, and  potential pest or disease problems.

Many trees on the list have moderate drought tolerance. These include flowering crabapple, Peking tree lilac, hackberry, giant dogwood and littleleaf linden.

Spell would like to see homeowners choose trees other than maples, if possible.

“Spokane is heavily overpopulated with them,” she said. “The next problem we face might not be a storm but rather a pest that hits maples or other trees. The pests might wipe them out. Diversity is so important.”

Have a certified arborist check your trees

Are you concerned about the stability of your partially damaged trees? Spell suggests having a certified arborist come out to assess the tree. There is a list of certified arborists available on the Spokane County Extension’s website.

She is worried about one thing, though. Many homeowners will have perfectly healthy trees cut down. Why? They’re worried about the fear and uncertainty that another windstorm will bring them down.

“The important thing to remember is that, in fact, those trees survived the strongest windstorm in history. We had 71 mile-per-hour winds.” she said. “In the city, there are well over 100,000 trees. I estimate about 1,900 trees came down. That isn’t that bad.”

Susan Mulvihill is co-author, with Pat Munts, of “Northwest Gardener’s Handbook.” Contact her at Susan@susansinthegarden.com and follow her on Facebook at facebook.com/susansinthegarden.

Resources

• City of Spokane Urban Forestry: (509) 363-5495, my.spokanecity.org/urbanforestry/
• Spokane Conservation District, Urban & Community Forestry: (509) 535-7274, sccd.org/departments/forestry/urban-community-forestry
• Approved Street Tree List: static.spokanecity.org/documents/urbanforestry/permits/street-tree-list-2015-04-03.pdf
• Inland Northwest Certified Arborists: http://ext100.wsu.edu/spokane/wp-content/uploads/sites/14/2015/05/C084-INW-Certified-Arborists-15a.pdf
• WSU/Spokane County Master Gardener plant clinic, 222 N. Havana; (509) 477-2181.
• Tree Planting and Care Information: http://ext100.wsu.edu/spokane/trees-and-shrubs/