1. Excavate the top 4-6 ins layer of dirt and fill back up with new topsoil of good quality. ( u9 a' _0 z% \* A) B2. Reduce the use of chemical fertilizer and use organic one instead.
6 M6 _0 A# D2 C0 H' K LI 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.