The back portion of my home lot has several oak and elm trees about 8 to 12 inches in diameter. It is a low lying area. I would like to fill in this area with soil to raise it a little. How many inches, if any, can I fill in, without damaging the trees.

Reply to post by jdharris, on April 23, 2000 at 16:41:50:

Generally speaking, adding soil over the rootsystem of established trees is a bad thing. Roots develop in the soil within a zone that allows for adequate water and oxygen to be available in the pore spaces within the soil. Roots take in oxygen from the soil and give off carbon dioxide, and when soil is added over roots, the rate that oxygen can be captured is often deminished. In time, roots begin to suffer due to a lowered available oxygen and an increase in carbon dioxide in the soil around them.

Some species are more sensitive then others, and pin oak is among the less sensitive. There are a variety of text-book models for adding material over rootsystems with systems for water infiltration and gas exchange, however, I have no personal experiance with installing them. Perhaps others on here do and can comment on them.

Wayne