Md. Code, Nat. Res. § 5-423

(a) A person may not: (1) solicit, advertise, or represent the person to the public as a tree expert, or assume to practice as a tree expert without having received a license; or (2) after having received the license and subsequently losing it by revocation or suspension continue to practice as a tree expert; or (3) use the title or abbreviation “L.T.E.” or any other words, letters, or abbreviations tending to indicate that the person is a licensed tree expert or a tree expert without having received a license, or when the license has been revoked or suspended. (b) If the owner of a tree employs any person to engage in the practice of a “licensed tree expert” as provided in § 5–415 of this subtitle, the owner is not subject to this penalty. (c) A person may not advertise that the person can provide tree services, including treatment, care, or removal of trees, unless the advertisement includes: (1) The license number of the licensed tree expert advertising tree services in one of the following forms: “Licensed Tree Expert No.___” or “L.T.E. No.___”; or (2) A statement that all tree services are limited to trees 20 feet tall or less.