A very comprehensive literature on the value of _forest litter_ was brought into existence by the established usage of small farmers of supplying their lack of straw for bedding and manure by substituting the litter raked from the forest. Hartig and Hundeshagen were active in the discussion of this subject as well as almost every other forester, the discussion being, however, mainly based on opinions. But, after 1860, the subject became so important both to the poor farming population and to the forest, which was being robbed of its natural fertilizer, that a more definite basis for regulating its use was established by analysis and by experiments at the experimental stations. With the inauguration of the various methods of forest organization described before, there naturally went hand in hand the development of _methods of measurement_. Better forest surveys developed rapidly, the transit generally replacing the compass and plane table. At this period the necessity for books teaching the important methods of land survey was met by _Baur_ (1858) and by _Krafft_ (1865). This subject does no longer occupy a place in forestry literature, the knowledge of it being taken for granted. On the other hand the subject of _forest mensuration_ which formerly was generally treated in connection with forest organization has developed into a branch by itself, and has been very considerably developed in its methods and instruments, making a tolerably accurate measurement of forest growth possible, although many unsolved problems are still under investigation. Still, late into the century it was customary to measure only circumferences of trees, by means of a chain or band, although an instrument for measuring diameters is mentioned by Cotta, in 1804, and by Hartig, in 1808. _Schœner_ and _Richter_ are in 1813 mentioned as inventors of the first “universal forest measure” or caliper. The improvement of calipers to their modern efficiency has been carried on since 1840 by _Carl_ and _Gustav Heyer_ and by many others until now self-recording calipers by (_Reuss_, _Wimmenauer_, etc.) have become practical instruments. For measuring the _heights_ of trees, _Hossfeld_ had already a satisfactory instrument in 1800; a very large number of improvements in great variety followed, with _Faustmann’s_ mirror hypsometer probably in the lead. As a special development for measuring diameters at varying heights _Pressler’s_ instrument should be mentioned, and a very complicated but extremely accurate one constructed by _Breymann_. Various formulas for the computation of the contents of felled trees had already been developed by _Oettelt_ and others in the eighteenth century and a formula by _Huber_, using the average area multiplied by length was definitely introduced in the Prussian practice in 1817. The names of _Smalian_, _Hossfeld_, _Pressler_ and others are connected with improvements in these directions.