[Illustration: Figure 60. A winter reconnaissance camp showing snow-shoes, skis, "Alaska" sleds, and bull hide used to repair the webbing on the snow-shoes. Lassen National Forest, California. Photo by the author.] _Special Contract Clauses._ Special clauses are inserted in contracts to meet peculiar and unusual conditions. These deal with the number of men the company is to furnish for brush burning; the time of the year this work is to be done; the construction of fire lines; the manner of scaling timber; the manner of piling and the location of piles of material to be scaled; the definition of a merchantable log; the utilization of tops; the manner or method of logging to be used; the location of improvements; the use of timber for the construction of improvements; the disposal of improvements at the termination of the contract; where cutting is to begin and how fast it is to proceed; the percentage of merchantable timber to be reserved in marking; and other special clauses recommended by the Bureau of Entomology for the sale of insect infested timber. That the Forest Service timber sale policy and the various timber sale clauses have met with the approval of the lumbermen and the timber buyers of the Western States is attested by the fact that in the last ten years (from July 1, 1907, to June 30, 1917) there have been nearly 75,000 purchasers of National Forest timber and that between these two dates the annual number of timber sales has increased from 5,062 in the fiscal year 1908 to 11,608 in the fiscal year 1917. No better evidence could be cited of the confidence which the lumbermen have in the Forest Service method of doing business. _When the Operation May Begin._ As soon as the contract has been executed and the first payment has been made a portion of the timber is marked for cutting and the purchaser may begin operations at once. Sometimes cutting in advance of the execution of the contract is allowed to prevent serious hardship and unnecessary delay and expense on the part of the purchaser. [Illustration: Figure 61. A group of giant redwoods. Santa Cruz County, California]