Cal. Rev. & Tax. Code § 38402

On or before the last day of the month following each calendar quarter, a return for the preceding quarterly period shall be filed with the board in such form as the board may prescribe. The return shall include the following information with respect to timber harvested by the timber owner in the preceding calendar quarter: the volume harvested and the number of Christmas trees cut; the quarter the timber was harvested and the quarter the Christmas trees were cut; the date or dates the timber was scaled; the species; and any other information deemed necessary by the board for the administration of this part. At the assessor’s request, the board shall provide copies of these returns to the assessor of the county from which the timber was harvested.