Is there a correlation between tree height and tree spread and the maximum diameter ( not radius from trunk ) that their roots will grow ?

  • 1
    Because nature is very variable and with many exception, it is usually better to ask about a specific problem, instead of asking for specific (in this case also not very specific) step. – Giacomo Catenazzi Oct 26 '17 at 7:04
  • Didn't want " root spread " but root thickness. For example, and not specific to a particular type of tree... If height is 30ft and spread is 20 what could max root thickness be.. 3", 4" or whatever ? – Murray Oct 27 '17 at 0:36
  • No, there is no correlation. It varies from species to species (like the trunk and branches, some spread more, with little but many branches, and some more regular and more "hierarchical"). Roots are similar. But I assume there is a correlation about the sum or section area of all roots and trunk section area (e.g. at one meter from "starting point" both ways) – Giacomo Catenazzi Oct 27 '17 at 6:57
  • Giacomo is totally correct: root thickness usually depends on location of roots in relation to the trunk - to make a broad statement, the closer to the trunk, the thicker the root (again, species has lots to do with this, as Giacomo noted, since you're far more likely to run into a large silver maple root than you are a large oak root). Please read the link I posted in my answer for more information. – Jurp Oct 28 '17 at 15:06

I was always taught that the roots of a tree extend 50% farther from the tree than the dripline, so if the crown of a tree is 50 feet in diameter, the root system is 75 feet in diameter. Of course, tree species, growing environment, and soil have a hand in this as well. Here's a short article from Iowa State (which has a fine Hort program BTW): Roots In Depth.

  • 2
    Yeah, this is the usual rule, so diameter and not height. But one should take care that efficiency of root is different between species. Some trees have shallow roots system, so not adapt on windy places, and more annoying on garden, because of "emerging" roots. – Giacomo Catenazzi Oct 26 '17 at 7:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.