California Code, Code of Civil Procedure - CCP § 1263.260

Notwithstanding Section 1263.210, the owner of improvements pertaining to the realty may elect to remove any or all such improvements by serving on the plaintiff within 60 days after service of summons written notice of such election.  If the plaintiff fails within 30 days thereafter to serve on the owner written notice of refusal to allow removal of such improvements, the owner may remove such improvements and shall be compensated for their reasonable removal and relocation cost not to exceed the market value of the improvements.  Where such removal will cause damage to the structure in which the improvements are located, the defendant shall cause no more damage to the structure than is reasonably necessary in removing the improvements, and the structure shall be valued as if the removal had caused no damage to the structure.