The question of the climatic significance of forests is one which first became recognized as capable of solution by scientific means when the movement for forest experiment stations began to take shape and the systematic collecting of observed data was attempted. Most of the problems are still unsolved. * * * * * With the aspects of _political economy_ in reference to forest policy the foresters had occupied themselves but little, leaving the shaping of public opinion to the Cameralists, whose influence lasted long into the century. These produced a good deal of literature in the early years of the century when the question of retaining or selling state forests was under discussion, and, under the influence of the teachings of Adam Smith, their opinion was mostly favorably to sale. Only gradually was the propriety of state forests recognized by them, till finally the leading economists, Rau, Roscher and Wagner, took a decided stand in favor of this view. The foresters naturally were for retention of the existing State properties, but one-sided mercantilistic views regarding their administration persisted with them till modern times. _Wedekind_, as early as 1821, advocated the theory which is now becoming a practice, that the state should not only retain, but increase its present forest property by purchase of all absolute forest soil for the purpose of reforestation. The erratic and radical Pfeil alone was found with the Cameralists on the opposite side in 1816, but, by 1834, he had entirely gone over to the side of the advocates of state forest, declaring anyone who opposed them fit for the lunatic asylum. Division of opinions existed also regarding the supervision by the state of private and communal forests. The political economists were inclined to reduce, the foresters to increase supervision, excepting again Pfeil in his earlier writings: he modified his views later by recognizing supervision as a necessary evil. Cotta, who was inclined to favor free use of forest property sought to meet the objections to such free use by increasing the state property.