As used in this Article, unless the context clearly requires otherwise:
(1) "Control zone" means an area of potential or actual infestation or infection, boundaries of which are fixed and clearly described in a manner to definitely identify the zone.
(2) "Forestland" means land on which forest trees occur.
(3) "Forest trees" means only those trees which are a part and constitute a stand of potential immature or mature commercial timber trees, provided that the term "forest trees" shall be deemed to include shade trees of any species around houses, along highways, and within cities and towns, if the same constitute insect and disease menaces to nearby timber trees or timber stands.
(4) "Infection" means attack by any disease affecting forest trees which is declared by the Commissioner to be dangerously injurious thereto.
(5) "Infestation" means attack by means of any insect, which is by the Commissioner declared to be dangerously injurious to forest trees.