(1) Upon award of sale, the purchaser shall execute a formal agreement. (2) The formal agreement shall: (a) describe the area on which the timber is to be cut, the approximate amount to be cut by species, and the rate for each product of each species; (b) stipulate that all timber shall be paid for in advance of cutting; (c) fix a date for termination of the agreement; (d) define rules of silviculture, cutting, utilization, scaling, and slash disposal; and (e) incorporate such other rules as in the discretion of the board of county commissioners are essential to the perpetuation of the county forests.