This 4 foot deep trench was dug six years after planting a row of trees two and one half feet from BiobarrierTM. The 12-inch deep barrier is six inches behind the soil wall on the right side of the trench. Roots (painted white) grew under the barrier and can be seen distributed at all depths on the right side of the trench (see arrows).
The barriers appeared to be deflecting roots to deeper soil layers compared to trees without the barriers. However, six feet from the barrier (left wall of the trench) most roots were in the top 12 inches of soil.