Part 1 of a 3-part series
It’s that time of year again to winterize your home and ready your yard for the winter storms which are so common in the Pacific Northwest.
Every year these storms cause damage to Portland Oregon and Vancouver Washington homes when high winds cause tree branches to break and even bring down the entire tree.
While it’s impossible to predict which trees will fall during a storm, there are things you can do to help limit damage caused by high winds and one of those is tree maintenance (preventative pruning).
Before we discuss that, let’s explain how trees are engineered to withstand normal wind conditions.
How do trees react to wind?
Trees are biologically designed to adjust to wind conditions. When it’s windy, trees sway back and forth and that movement causes the trunk to strengthen over time. This trait is called ‘wind firmness’ and most trees out in the open develop good wind firmness in all directions because they are exposed to a lot of wind. However, trees growing in confined spaces (like an urban or suburban yard) may not be as ‘wind firm’ simply because they are not exposed to wind as often.
Of course, normal wind conditions are different than the strong wind gusts that often accompany our famous winter storms. It’s these unusually strong winds that cause us to hold our breath as we watch the tree branches around our house whipping back and forth.
The trees in your yard are not only beautiful, they also increase your property value and are environmentally beneficial. With all this in mind, let’s talk about how we can possibly prevent your trees and/or your home from being damaged in high winds.
What is tree maintenance?
Also called preventative maintenance, preventative pruning or structural pruning, it covers a range of tree pruning services like crown cleaning or crown reduction. These services include removing small branches to allow wind to pass through and sunlight to reach all the branches and trimming weak, dead and/or decayed branches.
Research shows pruning prevents damage
A study was done to see if structural pruning would reduce tree damage. It was conducted using 120 mph wind and with 4 groups of trees.
1. No Pruning
2. Reducing-crown was reduced in height
3. Thinning-crown was thinned by removing primary branches back to the trunk
4. Raising-crown was raised by removed the lowest branches
The results showed that removing branches from the crown reduced trunk movement. This pruning lessened the amount of force to the trunk and roots and decreased the likelihood of trunk failure. The thinning and reducing groups showed the most positive results with the least amount of trunk movement.
How does pruning prevent damage?
Like the study above mentioned, selective thinning of branches allow wind to pass through rather than it acting as a wall that stops the wind. There’s much less resistance when wind passes through the tree than when the tree is so thick that it stops the wind so that the tree has to absorb the force of the wind.
Pruning isn’t the ONLY way to reduce storm damage. The key to prevention is to look for conditions that predispose a tree to damage and correct the problem before it can occur. These conditions or elements fall into general areas of concern which we will discuss on Part 2-Prevent Storm Damage.