En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?


Ask Mr. Smarty Plants

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Tuesday - December 16, 2008

From: Nashville, TN
Region: Southeast
Topic: Trees
Title: Distance from existing oak trees to place paving
Answered by: Barbara Medford


We are designing an expansion for an existing veterinary office and the desired side for expansion will require addition to the parking and drive aisle to the back side of the property. My question is this, how close can we install pavement to two existing oak trees (both trees have 60+ DBH). Thank you for your time and effort in your response.


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 parking within the dripline or piling of materials, waste, etc. in that 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.

We realize these are difficult restrictions, and your construction crews will not be happy. However,  you will need to make a choice between the trees and the construction. If you fail to make provisions for the needs of the trees, even if the trees appear to have survived, they probably have only a few years before they succumb to disease or starvation. 


More Trees Questions

Need help with a misshapen Monterey Oak in Austin, TX
March 11, 2010 - In the Fall of 2008, I purchased a very tall Monterey Oak from TreeFolks at the Burger Center Sale. Since the wind was so high, all the tall trees were on the ground, and I guess that is why I did no...
view the full question and answer

Searching for an Escarpment Black Cherry (Prunus serotina) for sale
October 16, 2007 - I am trying to find an Escarpment Black Cherry Tree for planting in my yard. Do you know of anyone that carries this particular type of tree?
view the full question and answer

Need plants to replace cedars on a 40 degree slope in Boerne, TX.
August 28, 2012 - My backyard is a roughly 40 degree slope that is covered with cedars. The slope is basically all rock, what can I grow here to replace the cedar which drink too much water. I would still like the area...
view the full question and answer

Trees for property in Nevada
April 06, 2013 - Mr. Smarty Plants: I would like to plant trees in between Crepe Myrtles than put up a fence along the paved road. The temperature ranges from 27'F to 130'F. It is a full sun all day and I will i...
view the full question and answer

Seasoning oak for burning
December 18, 2008 - I have an oak on my property that has been dead for at least two years. It has produced no leaves. When I cut it down (it was 93 inches around), it looked extremely healthy. We split it up and my f...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center