United States Forest Service Fig. 105. Compare this load of white pine logs, hauled out of the Minnesota forests over the snow, with the load shown in Figure 106. The difference helps to account for the fact that lum- bering is a winter occupation in the northern states. CHAPTER ELEVEN LUMBERING AND FOREST PRODUCTS Woop ranks with iron and coal as an aid to man in his attempts to rise in civilization. From the earliest times man has burned it to cook his food and to keep him warm. For thousands of years it has been the chief material for building his house. As time passes new uses are continually being found for this valuable substance. For instance, when railroads came into use wood was found to be the best material for the cross ties, and now a billion and a half cubic feet of wood are used annually for that purpose alone. Wood also furnishes good fiber for cheap, strong paper. A single newspaper firm in New York uses daily more than two hundred tons of paper, which means the product of more than three hundred cords of spruce wood. LUMBERING In view of the many uses of lumber, it is not surprising that the forests of the world are attacked every year by thousands of work- men, armed with axes and saws and equipped with all sorts of ma- chinery. Since we must have wood, even remote forests in rugged regions are made to give up their trees. 129