Hello! We are doing some site changes here at Country Campground just south...

Asked September 23, 2013, 5:21 PM EDT

Hello! We are doing some site changes here at Country Campground just south of Detroit Lake. We have some 18 y/o ash trees that are down in an area where we would like to fill in to bring up the grade of that area. I've read so much information online regarding things that can stress & kill a tree. We definitely do not want to lose these trees and would like some advice on what we should not do with our landscaping. We are kind of in a time crunch to complete these sites to get them seeded also.
At this time, we have fill dirt approx 7-10 deep within the dripline...but only on half of the the original dirt. We are thinking of building treated 4x4 boxes around the base of the tree 3 ft square to keep as much of the deep fill dirt away from the bark as possible...and considering adding mulch inside for appearance and safety as to not leave a hole to step into.
Any advice would be greatly appreciated! Todd Mitchell :-) 701-330-5678 countrycampground.org

Becker County Minnesota

1 Response

Changes in soil depth around trees can also cause injury to root systems. The addition of only 4 to 6 inches of soil over a root zone drastically reduces the amount of oxygen and water available to the roots and stress the trees. The 4x4 t
ree wells cannot compensate for the addition of soil over the tree roots. Check this link:

"Resist any urge to substantially raise the grade around a tree to facilitate under-planting. The impulse to add dirt around trees is strong, especially on trees with large shallow roots. The addition of more than a few inches of soil is unwise. The added soil can reduce water and oxygen supplies to existing roots, which will lead to the slow decline of the tree. Neither soil nor mulch should be piled up on tree trunks. This can lead to adventitious roots that can become stem-girdling roots."
"In some species, the roots regenerated after transplanting can grow back toward the trunk and become girdling roots. Initial research shows that very little soil over the structural roots could be problematic. Celtis occidentalis (hackberry), Fraxinus pennsylvanica (green ash), Acer rubrum (red maple), Tilia cordata (littleleaf linden), Populus spp. (poplars), and Malus spp. (crabapples) are species for which this is known to be a problem."

There are many more websites that warn against covering tree roots with soil, and the 4x4 wells wouldn't help that much since you need to fill the wells with compost.