Consider guarantee or service guarantees on pruning, treatments, and recently planted trees, with clear terms and timelines.

https://wiki-planet.win/index.php/Tree_Care_101:_Must-Know_Decisions_for_Working_With_a_Professional_Tree_Service_in_Columbus,_OH_16485

Think about warranty or service guarantees on pruning, treatments, and recently planted trees, with clear terms and timelines.