I keep seeing 'Tree of Life' designs at the local farmer's market, but every variation has even fewer roots than the classical celtic knot version, which is at least balanced top and bottom.<p>As these diagrams illustrate, a typical tree has roots reaching out at least 3x the radius of the 'root line' myth common among landscapers and construction workers. The truth seems to be more that any damage within that circle affects a pie slice of roots that are doing the real work. Cut a hole that's 18° wide and you can kill up to 5% of the roots.