Cal. Commercial Code § 2107

(1) A contract for the sale of minerals or the like (including oil and gas) or a structure or its materials to be removed from realty is a contract for the sale of goods within this division if they are to be severed by the seller but until severance a purported present sale thereof which is not effective as a transfer of an interest in land is effective only as a contract to sell. (2) A contract for the sale apart from the land of growing crops or other things attached to realty and capable of severance without material harm thereto but not described in subdivision (1) or of timber to be cut is a contract for the sale of goods within this division whether the subject matter is to be severed by the buyer or by the seller even though it forms part of the realty at the time of contracting, and the parties can by identification effect a present sale before severance. (3) The provisions of this section are subject to any third party rights provided by the law relating to realty records, and the contract for sale may be executed and recorded in the same manner as a document transferring an interest in land and shall then constitute notice to third parties of the buyer’s rights under the contract for sale.