_Timber Sale Contract Clauses._ The sale contract contains in full all the conditions under which the cutting is to be done. In all sales of National Forest stumpage the contract provides that no timber shall be cut until it has been paid for, and that it shall not be removed until it has been scaled by a Forest officer. All live timber is marked or otherwise designated before cutting, and any merchantable timber used for logging improvements, such as houses, bridges, stables, etc., must be scaled and paid for. In order to secure full utilization of the timber the maximum stump height is ordinarily fixed at 18 inches, and merchantable timber must be used to a specified diameter in the tops, which is adjusted for each species in accordance with local manufacturing and market conditions. The officer in charge of the sale is authorized to vary the stump height and top diameter in individual cases when those specified in the contract are not practicable. The tops must be trimmed up and, as a rule, brush must be piled and burned, or burned without piling under the direction of Forest officers. Merchantable timber which is not cut and removed and unmarked trees which are cut must be paid for at double the specified stumpage rates. This extra charge serves as a penalty. All camps, buildings, railroads, and other improvements necessary in logging and manufacturing the timber may be constructed upon National Forest land without charge. Railroads which open up inaccessible regions may be required to be made common carriers or to transport logs and lumber for other purchasers or for the Government at reasonable rates. Since fire protection is one of the most important duties of the Forest Service, provision is made in all contracts that the purchaser must place himself and employees, as well as the employees of his contractors, at the disposal of authorized Forest officers for fighting fires. Reimbursement is made for such services at the wages in vogue for fighting fires on the National Forest in question, unless the fire threatens the timber of the purchaser or property of the operator, or is started in connection with the operation. Under these conditions the purchaser is expected to furnish his available employees to assist the Government in fire fighting without charge. Efficient spark arresters are required on wood and coal burning boilers or locomotives. Inflammable material must be cleaned up in the vicinity of logging engines, and other precautions taken to insure against fire spreading from this source. Snags and diseased trees upon the sale area must usually be felled, whether merchantable or not, in order to remove fire menace and to check the spread of timber infestations and pests. [Illustration: Figure 59. Forest officers moving camp while engaged in winter reconnaissance work. All food, beds, and clothing are packed on "Alaska" sleds and drawn by the men themselves. Photo by the author.]