1. Excavate the top 4-6 ins layer of dirt and fill back up with new topsoil of good quality.1 g) A# M/ g4 J: L( ^* d$ p
2. Reduce the use of chemical fertilizer and use organic one instead.
7 i X0 X: l! T1 H( e" a/ B+ S% dI should tell a bobcat is required if you wanna do the whole front/back yard OR just spot-excavation (dig a bigger and deeper than normal hole, dump the old dirt and back fill w/ good topsoil when you want to plant a new tree) if you gonna do the job yourself.