Trees on the Level


This blog is about trees and how they grow out of the earth.  It sounds like a simple concept but not so fast.  I have seen many trees planted or maintained at the wrong level with dire consequences.  First let me explain what the issue is.  Tree bark and tree roots have different outsides.  Tree bark is not meant to be subterranean.  If it is buried, One of two things will happen.  And one of them is rot and death. 

The bark is built to keep insects and dryness out.  The protective layers keep the delicate meristematic tissues moist and dividing.  Bark is not built to be wet from the outside very long.  Oh, it can take rain and so forth, but continuous wetness will cause popping of the protective cell walls and rot.  Pathologic organisms can get an opportunity and make their way into the inner bark and tissues.  Once they are past the surface, they have an easier time of it rotting away the wood under the first few millimeters.  That can cause a cavity to develop and may allow pathogens the way into rotting the middle of the tree out.  Thus the “hollow” tree. 

The level at which the tree is growing relative to surrounding ground level is crucial.  If anything, the crown of the tree should be above the grade by about 6 inches.  If you want a visual, take a look at trees that grew from seed that landed on the top of the ground.

Root flare of a naturally grown White Pine

Surrounding soil too deep around trunk

Trees would all end up at the right level if we just let seeds fall and they grew naturally.  We do some modifying of our environment when we build homes and roads and driveways.  When we dig out a basement and spread the basement soil around the lot, we bury things that were already growing there in extra soil.  When we grade a driveway with topsoil, we taper soil along the concrete and bury trees nearby with extra soil.

If we buy a nursery grown tree, we often hear about how we should plant it at the level it was growing in the nursery.  I agree with a qualification.  Trees in the nursery row are often mounded up with soft soil from the cultivator.  This loose soil can build up around the trunk so when the tree is dug, it is too deep in the root ball.  Always tease out the top of the rootball or container and see where the roots begin to flare out into the soil.  Ideally, the root flares should be up out of the surrounding ground a little.

The other thing that will happen if trees are planted too deeply is that they may grow roots out of their bark, but that is another post and only a few trees can do this.



  1. Kevin said,

    December 14, 2009 at 8:29 PM

    I like your blog so far!

    • December 14, 2009 at 8:57 PM

      What are you doing reading people’s blogs? Shouldn’t you be studying for finals?

  2. Theron said,

    December 15, 2009 at 2:35 AM

    That is very useful information. Thanks for sharing your knowledge.

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