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What to do with under ground trees?

Discussion in 'Landscape Architecture and Design' started by francois, Sep 29, 2004.

  1. francois

    francois LawnSite Member
    Messages: 7


    I'm putting grass where the land has been filled to meet the building height. They put earth around 6 small trees (pines, maples) and the builder want to keep those. Today we dig around, so we now have 2 feet deep holes around each tree.
    For security reasons, those need to be filled. What should I use?

    Only 2 things come to my mind.

    Mulch: but I wonder if it will keep too much humidity and in 10 years from now, all that mulch will be composted and those trees will again be under earth.

    3/4 stone: this will certainly keep the humidity away from the trees but will the trees be able to push it away as it get bigger?

    Any hints welcome,



    PS: excuse my poor english
  2. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Doesn't matter what you use to fill them with They are going to die any way. You might as well cut them down now.

    Trees need to be planted higher rather than lower. Yes They will not die right away but get a wet season and they sure will from lack of air. The Top 8 inches (Rhizoshere) is where all plants get nutrients from, including AIR. Good Soil should have 50% solids matter 25% water at field capacity and 25% air. This is called Porosity and is important to sustaining Life.

    Now if you want to save the trees. Try removing the fill back down to the original level, and a couple yards passed the Drip Line and build a retaining wall.
  3. Coffeecraver

    Coffeecraver LawnSite Senior Member
    from VA.
    Messages: 793

    I agree with Ric

    Smothering roots by adding soil
    Most people are surprised to learn that 90% of the fine roots that absorb water and minerals are in the upper 6-12 inches of soil. Roots require space, air, and water. Roots will grow best where these requirements are met, which is usually very near the soil surface. Piling soil over the root system or increasing the grade will smother the roots. It only takes a few inches of added soil to kill a sensitive mature tree.

    Call a local Arborist to survey the trees and make recomendations.

    If you will post your zip code I will reply with a list
  4. Ric

    Ric LawnSite Fanatic
    Messages: 11,969

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