Established Trees and New Artificial Grass

Q. I have a small tree planted in 1998 that has roots growing under some artificial grass. It was put down many years ago. I have a tree that is sending big roots underneath this grass for probably 10 feet or so. This mound is probably 6 inches or more in height. I need to know if I pull this artificial grass back and cut that root if it would kill the tree.

Tree roots under artificial grass may be dead and can be removed.

A. Sounds like maybe the small tree was planted 23 years ago before the artificial grass was installed. If the tree was planted before the artificial grass then probably the tree roots got no water. If they got no water then the roots are dead and cutting them is no problem.

Ash tree roots grow where there is a steady supply of water, air and fertilizer. In the desert, ash trees need water and air first and fertilizer second. In lawns ash tree roots will grow near the surface of the soil because that is where the best balance of water and air can be found easiest. And when the lawn is fertilized, the tree loves it!

Will the Tree Fall Over?

So maybe the tree will fall over and maybe not. It would be difficult to say without looking and making some guesses. Tree roots provide anchorage for the tree as well as take up water. If the soil is dry under the artificial grass, then no roots are sent out by the tree or they die if there is none. Trees do not send roots out into dry soil, and they do not get larger unless they have access to water. Larger still if the get water AND air. So possibly that root is still alive. Find out for sure.

We don.t know but it looks like this tree will not get water from neighboring plants.

 Trees can "steal" water from neighboring landscapes, other plants, lawns and other places. As this tree gets larger it will need more water. It can get more water by adding emitters.

            Trees send roots out in one or more directions in the presence of water. Tree roots don’t respect property lines and walls. In sandy soil, moist soil can be found about 0 to 18 inches from a source of water. In a heavier loamy soil, moist soil will be further; maybe 18 to 36 inches from its water source. If roots find a preferred mix of water and air, they proliferate. If the soil stays dry, then they don’t. Tree roots, like us, are lazy. When we hand water mature trees we have to guess where the roots are. If water has been there over and over, then its a good guess roots are their too. If we continuously wet the soil in the same spot and its close to plants, roots will multiply.

Make an Educated Guess

            What to do? Look at the area and find the possible permanant sources of water where tree roots might grow. Those spots might have the greatest chances of tree roots. If there are plenty of places where water was applied, cut the offending root back in increments until the offending root is not a problem. Leave as much there as you can. 

Stake the Tree

Stake the tree for one to two seasons of growth and apply water to the same areas over and over that were not root pruned. Soon after the root was cut, prune the tree and remove one quarter to one third of its canopy. Check for reestablishment of the roots after the second year of growth. The first couple of years the tree will grow slowly. Generally, if tree roots growing from the trunk are evenly balanced, about half of all existing living roots can be removed without damaging the tree if they have balanced growth from the beginning.