The trees in the photos in this post are in a parking lot island in a large commercial development. Because of their size, I imagine they are original to the development, which was opened in the mid-1990s. All this time, the landscape maintenance crews have been refreshing the Mulch Mountains, piling them higher and higher as they spruce up the development each year ... and what you see below is the inevitable result.
When I saw this the other day, I knew that it was a perfect example to use to spread the word and try to educate folks about what can happen. (I could talk about this all day, but a graphic photo or two gets the point across a lot better.)
Piling mulch against the tree's trunk like this traps moisture and creates a perfect atmosphere for girdling roots to sprout around the tree trunk.
Most folks don't realize that mulch piled high against their trees can cause damage like this. They think that professional landscape crews must be experts, so why not do what they do. Don't fall for it!
If you choose to mulch the base of your trees or shrubs, try to keep the mulch from piling up against the trunk. In the long run, your trees will thank you.
Here's a video to show you how it's SUPPOSED to be done.