California Code, Public Resources Code - PRC § 4153

The department or its duly authorized agent may summon an able-bodied person to assist in suppressing a forest fire and may authorize an officer of the state, who is charged with the prevention and suppression of fire or the enforcement of the state fire laws, to summon an able-bodied person to assist in suppressing a forest fire within their respective jurisdictions.  An able-bodied person who is engaged in the harvest of perishable agricultural crops shall not, however, be summoned to assist in suppressing a forest fire until all other available workpower has been exhausted within the respective jurisdiction of the officer issuing the summons.  A member in good standing of a regularly organized fire department shall not be summoned if the member is available and subject to call for duty with a firefighting unit.