I have a rock landscape yard. Unfortunately the previous owners had put down landscape plastic, even right up to the trunks of the trees. I'm currently in the process of removing it all.

During this process I've noticed that the ground was totally damp beneath all the plastic, and it had been at least a month since it rained last. This leads me to believe that the trees have constantly been soaking in this damp soil. My native Mesquite trees don't look so hot. The bark is peeling off and sap oozes from them. Could this be in part because the damp soil? Now that I've removed the plastic will it get better or do I still need to take some sort of action?

Thanks in advance for your help!