Tree Well Maintenance

A tree well provides space around the trunk of a tree that is free of grass or weeds and is often covered with mulch. Tree wells, when done correctly, contribute to a tree’s overall health by providing the following benefits:
  • Preventing trunk damage by lawn mowers and weed eaters
  • Regulating soil temperature
  • Retaining soil moisture
  • Reducing competition between tree roots and weeds/grass
  • Improving aesthetics
While trees can reap great benefits from these maintained spaces around them, there are some misguided practices we frequently see that can actually have a negative impact on tree condition.
raised tree well.jpg

Excavated Tree Wells

A common practice when creating a tree well entails removal of soil around the edges of the ring. The logic behind this practice likely relates to catching rainfall in the basin that is created; however, soil removal can damage tree roots. Most absorptive roots grow within the top 12 inches of the soil, and this excavation can remove these important roots that are necessary for a tree’s access to water and minerals (which sort of defeats the purpose, doesn’t it?). If the tree is larger, most absorption takes place further from the trunk anyway, and larger roots can incur damage, increasing the potential for root rot and cutting off transport of these resources back into the tree.

Also harmful, the removed soil is often piled back within the tree well or even against the trunk. This addition of fill has its own set of consequences, which are described in the section below.

Raised Tree Wells

At the other end of the spectrum from soil removal, building up a tree ring by creating a border with rocks, bricks, or edging and filling it with soil (as shown in the photo above) can also adversely affect a tree. One main function of tree roots is respiration, the exchange of gases between roots and the atmosphere above ground. Addition of even a couple of inches of soil on top of a tree’s root system slows the rate of gas exchange and can ultimately result in stress and even root death. In addition, fill soil makes water less accessible to roots, and if piled against the trunk it can lead to rot.
mulched tree 1.jpg

Find a Happy Medium

When building a tree well, avoid removing soil if possible, and be careful to prevent damage to tree roots when removing grass and weeds from the area. If soil must be removed, try not to go too deep, make clean cuts on roots that are torn, and dispose of the soil elsewhere – do not pile it back on top of the root zone.

If you would like to create a border with rocks or other edging, this may still be accomplished by simply not filling the tree well area with soil. Add the border and then apply a 3-4” thick layer of mulch across the well, careful to keep mulched pulled away from the base of the trunk by a few inches.
Taking care to avoid these harmful practices when maintaining a tree well can help your tree to experience all of the benefits, without all of the stress.

View more topics from the Winter 2017 edition of Edmond Tree Mail
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