Maryland Code, Natural Resources § 5-412

(a) Any person who drives or operates a truck, trailer, or other vehicle upon any public highway, road, or street in the State for the purpose of transporting five or more trees, or 100 pounds or more of boughs, of any species of pine, spruce, fir, hemlock, or other narrow-leafed or broad-leafed evergreen tree or shrub, shall have upon his person during the transporting, a bill of sale for the trees, shrubs, or boughs signed by the owner or custodian of the lands from which they were cut or removed.

(b) The bill of sale shall state the date of sale; number and species of trees or pounds and species of boughs being transported; number of the election district, name of the county and state from which the trees, shrubs, or boughs were cut and removed; and the postal address of the landowner or custodian or whether they have been obtained from a dealer in these goods. The bill of sale or invoice shall show clearly the name and place of business from which the trees or boughs were obtained.

(c) This section does not apply to the transportation of trees, shrubs, or boughs by the owner or custodian of lands from which the trees, shrubs, or boughs were cut or removed or by the agent of the owner or custodian, or to transportation in a truck or trailer licensed to operate or engage in interstate commerce.