Pub. Resources Code, § 4716

(a) Whenever the director determines that there exists an area that is infested or infected with insect pests or plant diseases injurious to timber or forest growth and that the infestation or infection is of such a character as to be a menace to the timber or timberlands of adjacent owners, the director, with the approval of the board, may declare the existence of a zone of infestation or infection, and describe and fix its boundaries.

(b) If the director declares the existence of a zone of infestation or infection pursuant to subdivision (a), the department or its agents may go upon state and private lands within the zone of infestation or infection and shall cause the infestation or infection to be eradicated or controlled in a manner that is approved by the board.

(c) (1) Within a zone of infestation or infection, the department may remove live vegetation directly adjacent to dead or dying vegetation that is substantially at risk of infestation or infection.

(2) The department may also remove soil that harbors or could reasonably harbor insects or pathogens injurious to timber or forest growth, and that have the potential to facilitate the spread of insects or pathogens to live trees or could substantially increase the risk of subsequent infestations or infections.