Edward F. Gilman
Root barriers affect root distribution
Journal of Arboriculture 22(3): 151-154
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.