ArboristSite.com Sponsors
 
 


Flooded Oak Tree

Discussion in 'Arborist 101' started by nawlins, Mar 12, 2019.

Tags:
  1. nawlins

    nawlins New Member

    Joined:
    Mar 12, 2019
    Messages:
    2
    Likes Received:
    0
    Location:
    USA
    I recently bought a house in New Orleans, LA where the back yard slopes down to a mature oak tree. When it rains (which it does here a lot) it creates a mini lake around the base of the tree (see photo). It usually takes 4-5 days for the water to dissipate. I am concerned with hurricane season that flooding of my house/garage is possible, also it's a breeding ground for mosquitoes, lastly, I think it might be "drowning" the tree.
    Is it possible to add about 6" of a sandy soil to level the ground around the tree? Maybe not all the way to the base of the tree but a foot or so out?
     
  2. ATH

    ATH Addicted to ArboristSite

    Joined:
    Nov 18, 2006
    Messages:
    3,407
    Likes Received:
    2,064
    Location:
    Ohio
    How old is the house / how long has the landscape sloped that way?

    If the tree is well adapted to that moisture pattern, changing it may hurt the tree.

    If the water is sitting there that long, it is not able to drain down through the soil. Adding sand on top of it will just mean that the water is now sitting in sand instead of in a pool. Might help solve the mosquito problem, but not much else.

    Is there a way to get the water to flow out of there with a drainage tile or small trench? Is there a way to redirect the water that is ending up there elsewhere before it ends up there (for example if the downspouts go there, can you dump them to the front yard)??? Or, put a pump back there and pump it out (but to where?).

    Plant more "rain garden" plants there.
     
    Oldmaple and Jed1124 like this.
  3. Jed1124

    Jed1124 Addicted to ArboristSite

    Joined:
    Dec 2, 2009
    Messages:
    2,660
    Likes Received:
    3,350
    Location:
    NW,CT
    Sand or stone will create a “perched” water table. You have to try and get the water out of there like ATH said.
     
    Jason Douglas likes this.
  4. nawlins

    nawlins New Member

    Joined:
    Mar 12, 2019
    Messages:
    2
    Likes Received:
    0
    Location:
    USA
    Thank you for your advice!
    The house is 10 years old... I’m guessing the land has slowed down there at least that long.
    If I were to add more soil/sand to the yard... how close could I get to the base before effecting the health of the tree?


     
  5. ATH

    ATH Addicted to ArboristSite

    Joined:
    Nov 18, 2006
    Messages:
    3,407
    Likes Received:
    2,064
    Location:
    Ohio
    The roots from that tree go further out underground than the branches go above ground. However, most roots are in the top 18" of soil. Root depth is limited by oxygen availability in the soil. So, if you add 6" of soil, you've likely just killed 30% of your roots under that soil (adequate oxygen will still only go down 18"...). So I'll answer your question with another question "how many roots do you want to kill?". Not wanting to be rude or smart about it - just want to help you understand another reason that adding soil isn't a good solution.

    On a 10 year old house, without seeing the rest of the layout, I'd guess that they changed the grade during construction and caused more water to pool back there. That speculation is based purely on what I see in Ohio day in and day out. Might not be the case for your property... If that is the case, then you need to get the water out to maintain the health of the tree, not add more soil.
     
    Oldmaple likes this.
  6. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas
    If it's has water standing around it a lot of the time, then it's probably shallow rooted so it could blow over in high winds. This happens a lot when people keep there grass watered all the time and the tree roots don't need to go deeper for water.
    If it was me I would add an inch or two every year of soil around the base and slowly raise the ground level so water can't sit around it like it has been doing. Then I would thin out all the small inner limbs and reduce the wind load and over time it should force the roots to go deeper giving it a better chance of not blowing over.
    Like I said people love there green yard grass so the keep it watered all the time, so the roots don't have to go deep looking for water. Then after a big wind storm the tree will blow over taking half the yard with it.

    I grew tree farms for transplanting with a big john tree spade for over 30 years and the trees that were on a drip system always had shallow roots, The ones that were not on a drip system grew slower but had much deeper roots.
     
  7. Jed1124

    Jed1124 Addicted to ArboristSite

    Joined:
    Dec 2, 2009
    Messages:
    2,660
    Likes Received:
    3,350
    Location:
    NW,CT
    Not looking to get into a pissing match here but I don’t think this is good advice for the long term health of the tree.
    If you add soil over the course of years the lowest roots are going to slowly die due to lack of oxygen. Root development will continue to move upward where the oxygen is.
    If the interior branches are thinned, branch taper will be lost, and all of the force of wind on the tree will be out on the ends creating more fulcrum force on the tree increasing the chance of failure.
    If the objective is to reduce wind sail on the tree, selective reduction should be made out at the branch ends, reducing the overall wind profile of the tree. Interior branches should be left so that wind force is even throughout the canopy of the tree and branch tapor is retained.
     
    Jason Douglas and ATH like this.
  8. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas
    I disagree, but I'm not going to argue my point. I was only the tree business for over 30 years, so what do I know, rite.
     
  9. Jason Douglas

    Jason Douglas ArboristSite Guru

    Joined:
    Oct 23, 2016
    Messages:
    521
    Likes Received:
    335
    Location:
    Columbus
    What does that have to do with the physics of wind loading on the canopy?


    I would want to see the topo of the site but perhaps a pneumatic tool could help with some trenching and see the previous posts about drainage coming from your site and adding soil will create anoxic conditions for deeper roots.
     
  10. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas

    You can safely add an inch or two of soil each year around the base of a tree to cover exposed roots that stick up above the ground level and raise the ground level around the tree. But it takes time and you have to do it in stages and not all at once.
    If the tree is to big and you cant climb or use a bucket truck to reach the outer limbs, reducing the wind load, the next thing you can do is remove some of what you can reach without a climber or bucket truck. That is if you know the proper way of shaping and removing strategic limbs to help shape the tree and reduce the wind load at the same time. I was thinking the home owner might want to do it himself, instead of hiring a tree service to come do it. It all depends on how big the tree is and what tools and skill level the home owner has.
     
  11. ATH

    ATH Addicted to ArboristSite

    Joined:
    Nov 18, 2006
    Messages:
    3,407
    Likes Received:
    2,064
    Location:
    Ohio
    You can see how big the tree is. If you can't reach the outer limbs, you have no business saying you are going to reduce the wind load.

    But ...that is all irrelevant. Deal with the drainage and none of that conversation matters for this tree. Adding an inch of soil at a time means you only kill an inch of lower roots at a time. On a healthy tree, it can recover. For a tree that is struggling because it has suffered massive changes in its drainage patterns and soil conditions, those additional roots may be the difference.
     
    Jason Douglas likes this.
  12. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas
    Adding an inch a year to the base will not kill an inch of the roots each year. It's a natural thing for trees to gain or lose some top soil around the base do to erosion bringing soil in our washing it away, depending on the situation. I have done this hundreds of times when we transplant trees with a tree spade and the final grade ends up being to low or to high. And there are transplanted trees with 70% of the roots cut, so they can and do stress when moved. I have seen more tree drown when they sit in water to long. An established tree should have a 100% of the root structure intact so adding an inch of soil will not hurt the tree or kill any roots. The roots will adapt over time, that why you ad soil slowly.
    I agree getting the water away is the first thing I would do. Even a little pruning no mater how little, will certainly help reduce some of the wind load. It may not be much but a little is better then none.
     
  13. ATH

    ATH Addicted to ArboristSite

    Joined:
    Nov 18, 2006
    Messages:
    3,407
    Likes Received:
    2,064
    Location:
    Ohio
    Do you know what limits root depth in almost every circumstance?
     
    Jason Douglas likes this.
  14. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas
    Yes I do have a very good understanding of how the roots grow under different soils and conditions.
    When you dig a tree with a big john tree spade it leaves a perfect clean hole and you can see every root that has been cut and the depth and size of the roots and the direction they run.
    I tried to find a picture of the hole and the root system of a tree that has been dug up but I couldn't find one.
    Here is a few pics of some large trees being transplanted with a big john tree spade.
    I did it for over 30 years so I have transplanted tens of thousands of trees.

    [​IMG]

    In this picture you can clearly see the tap root sticking out the bottom and you can see some of the lateral roots as well. Notice the depth and angle of the roots that got pinched in between the blades
    [​IMG]

    This was my job for over 30 years.
    [​IMG]
     
    farmer steve likes this.
  15. ATH

    ATH Addicted to ArboristSite

    Joined:
    Nov 18, 2006
    Messages:
    3,407
    Likes Received:
    2,064
    Location:
    Ohio
    We get that you dug and moved trees for 30 years. But you didn't answer the question: what limits rooting depth?

    It is oxygen availability. When not enough oxygen gets through the soil, the roots stop going deeper. Adding more soil on the top means that the oxygen needs to go through more soil to get down there. If the deepest roots were on the verge of running out of oxygen before, then they certainly will run out when more soil is added on top. When they run out, they die.

    Like I said, if all else is well, I agree with you that an inch isn't going to hurt an otherwise healthy tree. However the particular tree in question MAY not be in good vigor? because of the saturated soil that it MAY not have been adapted to before construction 10 years ago. If the drainage is accomplished, there is no need to add soil on top and risk killing more roots.
     
    Jason Douglas likes this.
  16. sb47

    sb47 Addicted to ArboristSite

    Joined:
    Jun 14, 2011
    Messages:
    3,018
    Likes Received:
    2,974
    Location:
    Texas

    Thats why you use a top soil that is sandy and can breath well. If you put clay soil then yes you could slow down the oxygen penetration in the soil. However I have dug trees in many different soil types from all sand to solid clay. Clay soil tends to dry out in drought and cracks can form in the clay that reach down several feet and be as wide as 3''. so there is still oxygen reaching the deeper roots. The deep roots are mainly anchor roots and go deep looking for moisture. Trees on drip systems or in yards where the grass is kept watered, the anchor roots dont need to go deep looking for water so they stay on the top foot or so of soil. Slowly raising the ground level will start forcing the anchor roots to start going deeper and will anchor the tree better. But It takes time and you have to get rid of the standing water first before that can happen.
    It's hard to tell from a photo without being on site and getting the full picture of whats going on.
     
  17. Jason Douglas

    Jason Douglas ArboristSite Guru

    Joined:
    Oct 23, 2016
    Messages:
    521
    Likes Received:
    335
    Location:
    Columbus
    This tree needs a proper site history, and that of the surrounding houses, as part of a site analysis. How is that water getting there and why? On a related note, what species is it and is it a lowland oak?

    Removing lower interior limbs will be a proverbial drop in the bucket as far as reducing wind load. Wind velocity increases with height so overall force transferred to the root plate will be negligible at best if the concern is overall tree failure. In fact, removing lower interior growth, while admittedly reducing overall surface area, will reduce dampening and increase oscillation of the pruned limbs. This could therefore increase the likelyhood of a branch failure. See bending moment, fulcrum point, lion tailing, etc and the works of those in the field of tree biomechanics such as Mattheck, and Rinn amongst others.
     
    ATH likes this.
  18. Jason Douglas

    Jason Douglas ArboristSite Guru

    Joined:
    Oct 23, 2016
    Messages:
    521
    Likes Received:
    335
    Location:
    Columbus
    See also soil textural difference interfaces as it relates to drainage and aeration.

    Perched water table would be a good starting point.
     
    ATH likes this.

Share This Page