Prohibiting a person from physically engaging in the work of the treatment, care, or removal of certain trees for compensation under a tree expert's license unless the person is employed by the licensed tree expert, employs a licensed tree expert who can provide oversight, is employed by a company that employs a licensed tree expert who can provide oversight, or is a licensed tree expert; requiring a licensed tree expert to carry, show proof of, and maintain for a certain time period valid workers' compensation insurance; etc.