Cal. PRC § 4587

(a) Within five years after completion of timber operations on an area identified in a report submitted pursuant to Section 4585 or nonindustrial timber harvest notice, a report of stocking with respect to that area shall be filed by the timber owner or the owner’s agent with the department. A separate report of stocking may be filed with the work completion report for those areas which meet stocking requirements upon completion of timber operations. The board, by regulation, shall establish one or more statistically valid standardized sampling procedures designed to measure the number of trees and their dispersion.

(b) Notwithstanding subdivision (a), the board shall adopt regulations which specify the conditions and manner in which the necessity of employing sampling procedures may be waived. The regulations shall provide that, in addition to any other possible conditions which may be required by the board, the standard sampling procedures may be waived only if the director or the director’s representative and the timber owner, or a registered professional forester acting as the owner’s agent, agree that the area is adequately stocked to meet the standards of this chapter and any applicable rules or regulations of the board. The regulations shall require that, if the director or the director’s representative does not agree that the area is so stocked, a standardized sample shall be required.