- they grow fast
- they absorb a ton of water, which makes them heavy
- they’re a soft wood that breaks easily
- they grow in wet, unstable soil, which makes them prone to uprooting
- they have a shallow root system
- they can rot from the inside out, with no outward signs
What you need to know about cottonwoods
The cottonwood that we know in the Puget Sound region is the Black cottonwood (formally known as Populus Trichocarpa). This cottonwood is one of the three trees you see the most of in the Puget Sound lowlands, with the other two being Bigleaf maple and Douglas fir. This prevalence can be attributed to two factors: the tree’s love of water, and it’s rapid growth and propagation.
As you’ve probably noticed, they grow everywhere in Western Washington, particularly where the soil is wet – along river banks, in meadows, and in swampy areas. Their survival strategy seems to be “grow rapidly and in great quantity”, rather than slowly and with integrity. In some respects, the cottonwood is similar to a weed. It’s a pioneer species that grows rapidly and has a notoriously short life expectancy of around 25-30 years.
This life expectancy is so low, in part, because they often break and/or die suddenly. Their rapid growth, soft wood, and love of water all contribute to this. They grow in wet areas where the soil is often soft and unstable. This is because they love to suck up water – which is often their own downfall. A single tree will often suck up so much water that it’s own branches or trunk become too heavy to support. Factor in their naturally soft wood, and you’ve got the perfect storm for a widow-maker.
The cottonwood also has a relatively shallow root system, which means it’s just as likely to uproot and tip over in wet conditions as it is to break.
Finally, it’s important to know that these trees can be deceptive in their appearance, rotting from the inside and losing their integrity, while still looking like a healthy, solid tree.
How to deal with cottonwoods in your yard
In general, it’s never a bad practice to remove cottonwoods that are in proximity to structures, roads, powerlines, or people. However, some cottonwoods are perfectly healthy and provide all the benefits of a nice tree.
Here are some things that should make you wary about a cottonwood:
- Large size
- Leaning trees
- Particularly wet soil where the tree has access to a lot of water and the soil is unstable
- Growing on a slope or in a ditch
- Exposure to high winds
- Blight or evident rotting
Of course, not all of these conditions necessarily mean that you should immediately remove a tree. If two or more of these conditions are present, the risk and the stakes increase. Seasonal inspection of your cottonwoods is a good practice. If you’re at all uncertain about the hazard your trees pose, you can always get a little peace of mind by consulting an expert on the state of your tree.
