Why would a mesquite tree be oozing sap from it's substructure? We noticed yesterday that it is attracting lots of red wasps...

We noticed yesterday that it is attracting lots of red wasps to it's sap. Any philosophy on what is causing it to ooze sap?
I want to start my first garden but...
Answers:    If it an ripened and valuable tree surrounded by the landscape, I would own an arborist take a look at it. It is possible near is some kind of insect infestation or a disease process going on. An arborist would be capable of tell you if the tree can be save, or if it should come down.
Type of tree to plant?