The Trees Teach Us in the Wake of the Storm

a bulletin about tree health and wisdom
by ISA Certified Arborists: Gilbert A Smith and Lesley Bruce Smith

From above ground, it was the picture of health! Both of us, each with over 40 years of experience saving trees, looked at our 60’ Blue Spruce and never suspected that it was vulnerable. However, as we drove through town we noticed more Spruce trees down than any other species. Now we had to ask, why, what was going on? As we cleared up the mess in our yard, we decided to weigh some of the branches because they felt so unusually heavy. They averaged 70 lbs. each and the tree had about a hundred branches. When you add that to the weight of the trunk we were able to estimate the tree’s total above ground weight at about 5 tons. That is a lot of weight to get slammed around in 90 MPH winds. More on that later.

As we conferred with our neighbors in the aftermath of the storm, we discovered that this was the worst storm that anyone had ever experienced in Missoula. The meteorologists called it a derecho storm defined as a widespread, long-lived straight line windstorm. With winds above the city clocked at 109 mph, our neighbor’s perception was correct. It was a devastating wind that no-one could have predicted or prepared for.

Blue Spruce after Missoula MT storm — Photos by Lesley Bruce Smith

But why the preponderance of seemingly healthy Spruce trees destroyed? As the neighborhood began to gather around our failed Blue Spruce, everyone was convinced that it was because Spruce trees “have shallow roots”. This is a common misconception. Almost universally, people think that trees are held up by strong “tap roots”. This is one of the most damaging misconceptions about trees, that their roots grow deep into the soil. There have been many studies done by Land Grant Universities and the nation’s Arboreta showing that 90% or more of a tree’s roots are located in the upper 3 feet of soil. In fact, the roots of the 300 foot Giant Redwood trees live generally in the upper 6 feet of soil. This is because roots, like every other living organism, need oxygen to survive. They can’t find it deep in the soil. Arborists, like us, know that “shallow roots” were not the cause of the trees’ failure in this July storm.

So, eventually, we hiked up onto Blue Mountain, where the wind speeds were 19 miles per hour faster than in the Missoula Valley. You would have expected more damage up there, right? We found that it was just the opposite. Up in the forest on the mountain there was significantly less tree damage. By our estimation there was less than 1% of the trees that had experienced top breakage or wind throw. Wow! So what was going on down below that we lost so many trees and saw so much damage?

Here’s what two educated lifetimes of caring for and saving trees have led us to conclude. This is not rocket science. Trees are healthier when they are growing in a forest. That’s obvious, but why? First, they protect each other from the wind and from drought by growing close together presenting a barrier and a sun screen. Next, their roots, though not deep, grow together interlocking and supporting one another. Also their needles and leaves drop to the ground creating a layer of mulch that excludes competition, holds moisture and creates an environment, that has been scientifically proven, to double the amount of root growth that you will find in a suburban lawn environment. If that’s not enough, the trees on Blue Mountain, mostly Ponderosa Pine, Douglasfir and Larch are much less dense, due to the harsh windy and dry conditions which limit their growth and density. In addition, when the trees in the lawn are being watered, there is no incentive for the tree to extend its’ roots to collect water, as there is in the forest. That extension of roots make forest trees much stronger and more resistant to wind throw than the trees in the lowlands. Regular inspections and selective trimming by certified arborists to reduce the density of our Spruce trees would go a long way to prevent the catostrophic damage we saw in July.

We suppose that’s no consolation to all of us who have lost trees or had damage to our houses. But soon after the storm we noticed that our neighborhoods were losing even more beautiful trees. The whole feel and appearance of Missoula has changed, not just by storm damage, but by people removing trees for fear that they may fall in another storm. It is a natural fear based reaction that we understand. We saw the same fear after a tornado went through our old community near Chicago and in New York City after hurricane Sandy. However, we want you to know that removing our big trees is not the best answer. The trees, if planted properly and inspected and cared for by an experienced certified arborist protect us and add value to our property.

Most of us understand that trees add so much value to the environment and our property! So, what has taken 50 or 100 years to create is being lost in the space of an afternoon, all because of unnecessary fear. Please don’t overreact to the storm. Before you remove any trees just have them inspected by an In-ternational Society of Arboriculture Certified Arborist for safety and health. The inspections will help avoid the harmful removal of trees that could be saved. It would also help address the countless trees around town that are standing hazards with severe crown damage that should be repaired.

Recovering from this devastating storm has to include a plan next spring to replant new trees. The DNR Forestry Department in Missoula has an annual spring native sapling sale for habitat restoration. Native trees are much better equipped for handling the ravages of nature. By the way, Blue Spruce are not native to the Missoula Valley, even though we all love their stately structure and beautiful color. When native trees are planted properly, they will grow faster than you can imagine and remain longer in the landscape because of their adaptation to their native home. For future safety and beauty, have a Landscape Architect or Designer or Certified Arborist place your trees properly. If you plant on your own please follow these guidelines for success:

Plant trees far enough away from structures so their branches don’t hit them when the trees are mature.
If you have enough space, plant them in groups of 3 or more, not in lines so they can support and protect each other.
Mulch them out to the branch spread, or a minimum of 5 foot radius. This will double the amount of root growth making them healthier and faster growing. DO NOT use weed barriers between soil and mulch as they inhibit healthy nutrient recycling, moisture flow and healthy root development.
Segregate the lawn areas from the “forest”. Use your lawn to create pathways through the native plantings using shrubs, flowers and trees grown together in mulched beds. Native areas support wildlife, clean our water and air and provide habitat for our native pollinators and birds.
It takes about 1 year for a newly planted tree to get established. During that time they should be watered only once or twice a week for about an hour each time. If you water the trees as much as the lawn, in other words, every day, they will grow too quickly and become too dense, making them more susceptible to future wind throw. To maintain and save your beautiful big trees remember the importance of the following:

Have your trees inspected after heavy windstorms. When we live near trees they should also be inspected every 3 years by a Certified Arborist for safety and health. This practice may seem unnecessary or costly but it could save you many thousands of dollars down the road. Regular inspections and trimming are the very best preventative actions you can take to insure your trees remain healthy and safe though out their lifespans.

The good news is that a lot of storm damage CAN be prevented! Although we cannot prevent all tree damage by violent storms, in driving through the streets of Missoula we see many trees that have been weakened and damaged by the storm that could have had that damaged prevented if they had been regularly inspected and cared for along the way.