Why do trees topple over?

Published 9:00 am Saturday, January 22, 2022


Special to The Farmville Herald

One of our neighbor’s trees lays sprawled out in this picture and on top of another neighbor’s electric fence used to contain horses. It occurred to me that home gardeners could benefit from some discussion about why trees fall over and/or what we can do to prevent it.

Let’s start with what we can see from the picture. This was an end tree with another Leyland Cypress of about the same size just to the right of it. Several others are also planted in a row to the right undoubtedly to serve as a wind break. Notice the root ball (where the dirt is attached to the roots) is almost flat. This can indicate that when this tree was standing, few or no large roots grew horizontally in the direction of the other trees in the row. Without larger anchoring roots, this tree is weakened. Now add to that the fact that this tree is known for growing a large canopy very quickly. It has a huge canopy and by comparison a small root mass. Since this tree has never been pruned, there is little opportunity for the roots to catch up. While the recent winds had a role to play in pushing this massive tree over, it was further aided by wet soggy soil that routinely collects near where the tip of the tree currently lays. Based on this case study, you likely have some ideals how to prevent such an occurrence, but here are a few to help you out:

• General rule of thumb, “Choose the right tree for the right location”

• Encourage healthy root development, while some trees can thrive in saturated soil, most will not

• Space trees out so that the mature root mass will not be competing with other trees, roads, or other highly compacted areas

• Do not “Volcano Mulch” while mulch is great to hold moisture in the root zone (an area about the size of the canopy, but in the soil), creating a mound of mulch that buries the trunk or root flare, encourages rot and stress for mature trees

• Prune trees, especially when they are young, this creates less wind resistance while the roots develop

• If you want to provide additional fertilizer place it where the young tender roots are growing near the edge of the root zone not at the base of the tree

Fortunately, for our neighbor, this is not a fruit tree he planted and valued particularly. I could imagine how disappointing it would be to have waited 8 to 10 years for a pecan tree to produce only to have it blow over. Hopefully you are more prepared to Choose the right tree for the right location.