1. Excavate the top 4-6 ins layer of dirt and fill back up with new topsoil of good quality.7 r. a& Q" f% n' O. M0 i8 p' b/ h
2. Reduce the use of chemical fertilizer and use organic one instead.
2 w1 T% B* U" m" w6 u" xI 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.