En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Adjustments to soil level change around tree from Austin

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.

Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Thursday - May 29, 2014

From: Austin, TX
Region: Select Region
Topic: Planting, Trees
Title: Adjustments to soil level change around tree from Austin
Answered by: Barbara Medford

QUESTION:

I am moving in to a new construction home in south Austin, builder has leveled the ground and sodded the front yard, I have a post oak in the front and because of the changes to the landscape the tree root flares are below ground now and builder made a ditch round that, now after every rain a puddle is around the tree and it stays for day or two, is it harmful to the tree? How to prevent that? Thanks.

ANSWER:

It's hard for us to comment on that method of saving a tree affected by changing levels around  existing roots, so we are going to look first at previous questions to see if someone else on the Smarty Plants Team has had an insight that we don't. From Tequesta FL, Changing the Grade Over Mature Oak Roots. From there, we will go to the Internet. For your information, we will be searching on "tree well" as that is usually the technique used for protecting an existing tree when the ground level around it is altered. In one previous answer, we found this link to an article from Arborilogical Services on Dangers of Root Disturbance..

From West Virginia University Education Extension, here is an article on tree wells that has very clear instructions on how much dirt may (or may not) be allowed to remain over the roots, drainage, etc. From Texas A&M AgriLife Extension Protecting Existing Landscape Trees from Construction Damage.

 That article first addresses exposing the tree roots with removal of dirt, and then addresses the problem of covering those roots with soil or grass:

"Raising the Grade:
Raising the soil level around a tree is the most
serious grade change. Air circulation is cut off and
moisture and nutrients cannot reach the tree roots.
In some cases drainage is greatly impaired and the
tree drowns."
From another previous question:

"An oak tree root system is extensive but shallow. The ground area at the outside edge of the canopy, referred to as the dripline, is especially important. The tree obtains most of its surface water here, and conducts an important exchange of air and other gases. Any change in the level of soil around an oak tree can have a negative impact. The most critical area lies within 6 to 10 feet of the trunk. No soil should be added or scraped away from that area. Construction activity is a great threat to trees. Do not allow any piling of materials, waste, etc. in the dripline area.

Paving should be kept out of the dripline and no closer than 15 feet from the tree trunk. If at all possible, use a porous paving material such as brick with sand joints, open bricks, bark, gravel, etc., which will allow some water penetration and gas exchange. Even with porous paving, the area around the trunk-at least a 10 foot radius-should be natural and uncovered."

Our summary of all this information is that, at the very least, you must provide drainage out of that trench. From the various sources we have provided you, we hope we have given you information you can use in your specific case. Without being able to see the space in question, we believe that there is too much obstruction over the vital tree roots to permit the absolutely necessary exchange of gases and nutrients.

 

 

More Trees Questions

Safety of hyrbrid and non-native trees for dogs and horses from Lawton OK
March 25, 2013 - Are Arrowwood Viburnum tree, Sargent Crabapple tree & the Washington Hawthorn tree safe for dogs & horses?
view the full question and answer

Area under live oaks from Austin
October 08, 2012 - We have many live oaks in our mostly shaded half acre. While I have tried to plant mostly native plants, often beneath them, the plants are showered with leathery leaves, acorns and sap, while oak sp...
view the full question and answer

Solution for wet area near fence
April 07, 2010 - I just moved into a house that is 10 years old on the north side of Houston, Texas. When it rains the water pools about 1 to 3 inches deep around the beds with trees (pine, sweet gum and chinaberry) ...
view the full question and answer

Planting spot for sycamore in Belle Mead NJ
April 19, 2010 - At school we all got a tree. It was a Buttonwood tree, which I know is REALLY big, but my grandma wants to plant it near other trees. Where should I put it? My dad won't let me plant it in the middle...
view the full question and answer

Ornamental plants for under live oaks
September 08, 2008 - What ornamental plant will do well under Live Oak trees?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center