11/28/2011 11:11 AM
Root pruning is a successful, short term method to prevent competition with surrounding turfgrass. However, research has shown that severed roots will then shoot out even more growth after pruning.
I participated in the Great Southern Tree Conference last year in which some of the research being conducted by Dr. Edward Gilman at the University of Florida included evaluating different methods and types of root barriers from the bio-barriers, to plastic, to metal and even concrete. His research concluded that none of the barriers completely stopped root intrusion. However, some of them did slow down the effects the roots have on surrounding landscape.
An excerpt from this research specifically on Bio-Barrier:
"No roots of live oak (Qurecus virginiana) or sycamore (Platanus occidentalis) went through BiobarrierTM during a 3-year period after planting. Most roots on both species without a barrier were located in the top 30 cm (12 in) of soil, and root number decreased with increasing soil depth. Roots were located at deeper soil depths beyond the Biobarrier. The roots 15cm (6 in) from the Biobarrier were mostly 30 to 45 cm (12-18 in) below the soil surface. Eighty percent of oak roots and 72% of sycamore roots greater than 3 mm in diameter 0.9 m (3 ft) from the trunk without a barrier were in the top 30 cm (12 in) of soil, whereas, only 42% (oak) and 38% (sycamore) of roots were in the top 30 cm (12 in) for trees with the root barrier. Biobarrier forced roots deeper in the soil but in the high water table in this study, many roots returned to the soil surface by the time they had grown 1.2 m (4 ft) away from the barrier."
In short, the barriers do help temporarily, but the roots will eventually make their way under the barriers and back to the surface again. To get an expert opinion, I think Dr. Gilman would be your best source as he is considered the barrier guru. He had some pretty neat experiments going on up there.
Hope this helps.