Roots growing through synthetic fabric can be girdled
Many roots are growing through the synthetic fabric on this oak tree several years after planting. However, the right hand photo shows that most of the roots are being strangled or girdled by the fabric because the fabric is not decomposing in the soil.
Close up: Note the swelling where the root meets the fabric (big arrow). The small arrow shows the small diameter of the root that penetrated the fabric but was unable to expand in the hole in the fabric.