The value of the exports of forest products and timber industries reaches about eighteen million dollars a year, and the combined forest industries furnish employment to a large number of laborers. The state forests occupy about 3,500 square miles, more than half being located in the northern provinces of Tromsö and Finmark. The state also has nurseries at Vossevangen and Hamar, and three forestry schools, by means of which widespread interest in tree-planting has been aroused. Destructive forest fires and the slaughter of the trees by the remarkable development of the wood-pulp industries have emphasized in recent times the need of larger forest reserves and closer government supervision. Under the most favorable conditions, the pine requires from seventy-five to one hundred years to yield timber twenty-five feet in length and ten inches in diameter at the top. Spruce will reach the same size in seventy-five to eighty years. In the higher altitudes of the central part of the country the pine requires one hundred and fifty years, and rarely exceeds one hundred feet in height, and it decreases toward the coast and northwards. The fisheries of Norway are among the most important in the world, yielding the nation more than seven million dollars a year, and furnishing employment to eighty thousand men. The sea-fisheries play the chief part in this branch of industry. The long coast line and the great ocean depth near the coast combine to give the fisheries of Norway unusual advantages. The abundance of fish is also due to the presence of masses of glutinous matter, apparently living protoplasm, which furnishes nutriment for millions of animalcules which again become food for the herring and other fish. The fish are mainly of the round sort found in deep waters, the cod, herring, and mackerel being the most important. The cod yields the largest monetary returns. This fish migrates to the coast of Norway to spawn and in search of food. The best cod fisheries are in Romsdal, Nordland, and Tromsö counties, the Lofoten islands in Tromsö alone furnishing employment to more than four thousand men. The cod weighs from eight to twenty pounds and measures from five to six feet in length. Some are merely dried after having been cleaned. This is done by hanging them by the tail on wooden frames. The others are sent to the salting stations where they are salted and dried on flat rocks. A fish weighing ten pounds will yield two pounds of salted cod, the loss being due to the removal of the head and entrails and the drying out of the water. There are numerous secondary products from the cod, the most valuable being the cod liver oil. The livers of the fish are exposed to a jet of superheated steam which destroys the liver cells and causes the small drops of oil to run together. The roe are salted and sent to France to be used for bait in the sardine fisheries.