Part 10

This policy of freedom was also applied, although less radically, in Bavaria, except as to smaller owners. The result was, to a large extent, the increase of exploitation and forest devastation, creating wastes and setting shifting sand and sanddunes in motion. The reaction, which set in against this unrestricted use of forest property, resulted in Prussia not in renewal of restrictive measures, but in the enactment of promotive ones. The law of 1875 sought improvement by encouraging small owners to unite their properties under one management; but the expectations which were founded on this ameliorative policy seem so far not to have been realized.

This promotive policy has especially since 1899 found expression in the institution in many provinces of information bureaus, which give technical advice, make working plans, secure plant material and give other assistance to woodland owners.

A new relation, however, of a conservative character arose by the establishment of the entail, i.e., a contract made by the head of the family with the government under which the latter assumes the obligation of forever preventing the heirs from disposing of, diminishing, or mismanaging their property. As a result of this arrangement, many of the larger private forest properties are forced to a conservative management, not as a direct influence of the law, but as a matter of agreement. The condition of state supervision of private and communal forest property at present prevailing is expressed in the following statement of divisions by property classes of forest areas of Germany, which shows that at least 63.9% are under conservative management:

Total Forest 34,769,794 acres. Crown forest 1.8% State forest 31.9% Corporation forest 16.1% Institute forest 1.5% Association forest 2.2% Private forest (10.4% entail) 46.5%

Until the beginning of the present century, the protective function of the forest had played no role in the arguments for state interference, but just about the beginning of the century cries were heard from France that, owing to the reckless devastation of the Vosges and Jura Alps by cutting, by fires and over-grazing, brooks had become torrents, and the valleys were inundated and covered by the debris and silt of the torrents. A new aspect of the results of forest devastation began to be recognized, which found excellent expression in a memoir by _Moreau de Jonnès_ (Brussels, 1825), on the question “What changes does denudation effect on the physical condition of the country.” This being translated into German by Wiedenmann, was widely spread, being interestingly written, although not well founded on facts of natural history and physical laws. Nevertheless, sufficient experience as regards the effect of denudation in mountainous countries had also accumulated in southwest Germany and in the Austrian Alps, and the necessity of protective legislation was recognized. This necessity first found practical expression in the Bavarian law of 1852, in Prussia in 1875, and in Württemberg in 1879. But a really proper basis for formulating a policy or argument for protective legislation outside of the mountainous country is still absent, although for a number of years attempts have been made to secure such basis.

8. _Forestry Science and Literature._[5]

[5] The necessarily brief statements which are made under this heading presuppose knowledge of the technical details to which they refer. In this short history it was possible only to sketch rapidly the development of the science in terms familiar to the professional man.

The habit of writing encyclopædic volumes, which the Cameralists and learned hunters had inaugurated in the preceding century, continued into the new one, and we find _Hartig_, _Cotta_, _Pfeil_ and _Hundeshagen_ each writing such encyclopædias. _Carl Heyer_ began one in separate volumes, but completed only two of them. Even an encyclopædic work in monographs by several authors was undertaken as early as 1819 by _J. M. Bechstein_, who with his successors brought out fourteen volumes, covering the ground pretty fully. While in the earlier stages the meager amount of knowledge made it possible to compress the whole into small compass, the more modern encyclopædias of _Lorey_, _Fürst_ and _Dombrowski_ arose from the opposite consideration, namely, the need of giving a comprehensive survey of the large mass of accumulated knowledge.

Since 1820, monographic writings, however, became more and more the practice. Among the volumes which treat certain branches of forestry monographically, the works of the masters of silviculture, _Cotta_, _Hartig_ and _Heyer_, based on their experiences in west and middle Germany, and of _Pfeil_, referring more particularly to North German conditions, were followed by the South German writers, _Gwinner_ (1834), and _Stumpf_ (1849). In 1855, _H. Burkhardt_ introduced in his classic _Säen und Pflanzen_ a new method of treatment, namely, by species, and after 1850, when the development of general silviculture had been accomplished, such treatment by species became frequent. Of more modern works on general silviculture elaborating the attempts at reform of old practices those of _Gayer_ (1880), _Wagener_ (1884), _Borggreve_ (1885), _Ney_ (1885), all writing in the same decade, are to be especially mentioned. In this connection should be also noticed _Fürst’s_ valuable collective work on nursery practice (_Pflanzenzucht im Walde_, 1882).

At present the magazine literature furnishes ample opportunity to discuss the development of methods in all directions. The text books at present appearing seem to be justified by or intended mainly for the needs of the teacher and rarely for the practitioner. Such a text book is that by _Weise_. But the latest contributions to silvicultural literature by _Wagner_ (1907), and _Mayr_ (1909) are works of a new order, utilizing broader ecological knowledge.

Other branches than silviculture were similarly first treated in comprehensive volumes and then in monographic writings on special subjects of the branch. The literature on _forest utilization_ covering the whole field, was enriched especially by _Pfeil_, _Koenig_, _Gayer_, and _Fürst_. The first investigation into the physical and technical properties of wood was conducted by _G. L. Hartig_ himself, followed by _Theodor Hartig_, and the subject has been most broadly treated by _H. Noerdlinger_ (1860). In later years, _Schwappach’s_ investigations deserve special mention.

The question of means of _transportation_ gradually became also a subject capable of monographic treatment and a series of books came out on locating and building forest roads. _Braun_ issued such a book in 1855 for the plains country, and _Kaiser_ (1873) for the mountains, also _Mühlhausen_ (1876), who had been commissioned to locate a perfect road system over the demonstration forest at the forest academy of Muenden. Only within the last quarter of the century were railroads introduced into the economy of forest management. The first comprehensive book on the subject of logging railroads was issued by _Foerster_ (1885), and a later one by _Runnebaum_. _Stoetzer_ (1903) furnished in his compact style the latest discussion on the subject of roads and railroads.

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.

The idea of _form factors_ and their use was first developed by _Huber_, who made three tree classes according to the length of crowns, measured the diameters six feet above ground, and used reduction factors of .75, .66, .50 for the three classes. But the first formula for determining form factors is credited to _Hossfeld_ (1812). _Hundeshagen_ and _Koenig_ also occupied themselves with elaborating form factors. _Smalian_ (1837) introduced the conception of the _normal_ or true form factor relating it to the area at one-twentieth of the height. An entirely new idea has lately been introduced by _Schiffel_, an Austrian German, under the name of form quotient, placing two measured diameters in relation.

_Volume tables_ giving the volumes of trees of varying diameters and height were already in use to some extent in the 18th century; _Cotta_ gives such for beech in 1804, and, in 1817, furnished a new set of so-called normal tables which were, however, based upon the assumption of a conical form of the tree. _Koenig_ perfected volume tables by introducing further classification into five growth classes (1813), published volume tables for beech and other species, and, in 1840, published volume tables not for single trees but for entire stands per acre classified by species, height and density; using the so-called space number which he had developed in 1835 to denote the density. It is interesting to note that these tables, which he called _Allgemeine Waldschætzungstafeln_, were made for the Imperial Russian Society for the Advancement of Forestry.

In 1840 and succeeding years, the Bavarian government issued a comprehensive series of measurements and a large number of form factors, which were used in constructing volume tables; these were found to be so well made and so generally applicable that they were used in all parts of Germany and, translated into meter measurement by _Behm_ (1872), are still generally in use, although new ones based upon further measurements have been furnished by _Lorey_ and _Kuntze_.

For arriving at the _volume of stands_, estimating was relied upon long into the nineteenth century, although _Hossfeld_, in 1812, introduced measuring, and the use of the formula AHF, in which A was the measured total cross-section area of the stand, H and F the height and form factors, the latter being at that time still estimated. He first made form classes for the same heights, but, in 1823, simplified the method by assuming an average form factor for the whole stand. Even in 1830, _Kœnig_ still estimated the form factor, although he introduced the measurement of the cross-section area and determined the height indirectly as an average of measurements of several height classes, but _Huber_ (1824) knew how to measure both the average height and form factor by means of an arithmetic sample tree. This method found entrance into the practice and held sway until about 1860, when the well-known improvements by _Draudt_ and _Urich_ supplanted it. These last mentioned methods have become generally used in the practice, while other methods, like R. Hartig’s and Pressler’s, have remained mainly theoretical.

The study of the increment and the making of yield tables which had been inaugurated toward the end of the last century, by _Oettelt_, _Paulsen_, _Hartig_, and others, was just at the end of that century placed upon a new basis through _Späth_ (1797), who constructed the first growth curves by plotting the cubic contents of trees of different ages, and through _Seutter_ (1799) by introducing stem analysis, on which he based his yield tables.

On the shoulders of these, _Hossfeld_ (1823) built, when he conceived the idea of using sample plots for continued observation of the progress of increment, and he also taught the method of interpolation with limited measurements, laying the basis for quite elaborate formulæ. But the first _normal_ yield tables, based on the average trees of an index stand, were published by _Huber_ (1824) and, in the same year, by _Hundeshagen_. From that time on, yield tables were constructed by many others, but only since the Experiment stations undertook to direct their construction is the hope justified of securing this most invaluable tool of forest management in reliable and sufficiently detailed form. Even the newest tables are, however, still deficient, especially in the direction of detailed information regarding the division into assortments. The yield tables of _Baur_, _Kuntze_, _Weise_, _Lorey_, and others are now superseded by those of _Schwappach_ for pine and spruce, and of _Schuberg_ for fir.

As a result of the many yield tables which gradually accumulated, the laws of growth in general became more and more cleared up and finally permitted their formulation as undertaken by _R. Weber_ (_Forsteinrichtung_, 1891).

The idea of using the percentic relations for stating the increment, and of estimating the future growth upon the basis of past performance for single trees was known even to _Hartig_ (1795) and _Cotta_ (1804) who published increment per cent. tables. The methods of making the measurements of increment on standing trees were especially elaborated by _Koenig_, _Karl_, _Edward_ and _Gustav Heyer_, _Schneider_ (his formula, 1853), _Jaeger_, _Borggreve_, and especially by _Pressler_ (1860) who opened new points of view and increased the means of studying increment by causing the construction of the well-known increment borer, and in other ways.

The most modern text-book which treats fully of all modern methods of forest mensuration giving also their history is that of _Udo Müller_ (_Lehrbuch der Holzmesskunde_, 1899), superseding such other good ones, as those of _Baur_ (1860-1882), _Kuntze_ (1873), _Schwappach_ (short handbook, last edition 1903).

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The many sales of forest property which took place at the beginning of this period naturally stimulated the elaboration of methods of _forest valuation_. Even the soil rent theory finds its basis at the very beginning (1799) in a published letter by two otherwise unknown foresters (_Bein_ and _Eyber_), who proposed to determine the value of a forest by discounting the value of the net yield with a limited compound interest calculation to the 120th year. This idea was elaborated, in 1805, by _Nœrdlinger_ and _Hossfeld_ into the modern conception of expectancy values, and the now familiar discount calculations were inaugurated by them. _Cotta_ and _Hartig_ participated also in the elaboration of methods of forest valuation; Cotta writing his manual in 1804, recognizes the propriety of compound interest calculations, while Hartig, 1812, still uses only simple interest, and exhibits in his book as well as in his instructions for practice in the Prussian state forests rather mixed notions on the subject.

Altogether, even in the earlier part of the period, there arose considerable difference of opinion and warm discussions, in which all the prominent foresters took part, as to the use of interest rates and methods of calculation. But this warfare broke into a red hot flame when _Faustmann_ (1849) with much mathematical apparatus developed his formula for the soil expectancy value, and when _Pressler_ and _G. Heyer_ transferred the discussion into statical fields, making the question of the financial rotation the issue. Then the advocates of the soil rent and of the forest rent theories ranged themselves in opposite camps. This war of opinions, although abated in fervor, still continues, and the issue is by no means settled.

The discussion of what should be considered the proper felling age or rotation naturally occupied the minds of foresters from early times; a maximum volume production being originally the main aim. As early as 1799, _Seutter_ had recognized the fact that the culmination of volume production had been obtained when the average accretion had culminated. _Hartig_, in 1808, made the distinction of a physical, an economic and a mercantilistic, i.e., financial felling age, and _Pfeil_, considerably ahead of his time, is the first to call (1820) for a rotation based on maximum soil rent. As, however, he had so often done, he changed his mind, and while he first advocated even for the state a management for the highest interest on the soil capital involved, he later rejected such money management. About the same time _Hundeshagen_ clearly pointed out the propriety and proper method of basing the rotation on profit calculations, but it was reserved for a man not a forester to stir up the modern strife for the proper financial basis, namely _Pressler_, a professor of mathematics at Tharandt, who became a sharp critic of existing forest management, and developed to the extreme the net yield theories.

It was then that the danger of a shortening of the existing rotations, due to the apparent truth that long rotations were unprofitable, called for a division into the two camps alluded to; _G. Heyer_, _Judeich_ and _Lehr_, elaborated especially the mathematical methods of the soil rent theory, _Krafft_ and _Wagener_ came to the assistance of Pressler, while _Burkhardt_, _Bose_, _Baur_, _Borggreve_, _Dankelmann_, _Fischbach_ and others, pleaded for a different policy for the state at least, namely, the forest rent with the established rotations.

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As in the previous period, the mathematical subjects, namely, forest measurement and forest valuation, were more systematically developed than the _natural history_ basis of forestry practice; the slower progress of the latter being caused by the greater difficulties of studying natural history and of utilizing direct observation.

In _botanical_ direction, descriptive forest botany was first developed, and several good books were published by _Walther_, _Borkhausen_, _Bechstein_, _Reum_, the latter (1814), of high value, and also by _Behlen_, _Gwinner_ and _Hartig_.

In the direction of plant physiology, _Cotta_, early and creditably, attempted (1806) to explain the movement and function of sap, but remained unnoticed. _Mayer’s_ (1805-1808) essay on the influence of the natural forces on the growth and nutrition of trees, contains interesting physiological explanations for advanced silvicultural practice. But these sporadic attempts to secure a biological basis were soon forgotten. Not until _Theodor Hartig_ (1848) published his Anatomy and Physiology of Woody Plants was the necessity for exact investigation of forest biology as a basis for silvicultural practice fully recognized. With the development of general biological botany or ecology, a new era for silviculture seems to have arrived. Perhaps in this connection there should be mentioned as one of the earlier important contributions of much moment, _G. Heyer’s_ _Verhalten der Bäume gegen Licht und Schatten_ (1856) in which the theory of influence of light and shade on forest development was elaborated.

Among those who placed the study of pathology of forest trees on a scientific basis should be mentioned first _Willkomm_ (1876), followed by _R. Hartig_.

In _zoölogy_, the early writers began with a description of the biology of game animals. Next, interest in forest insects became natural, and, in 1818, _Bechstein_ in his Encyclopædia devoted one volume (by _Scharfenberg_) to the natural history of obnoxious forest insects. Toward the middle of the century, with the planting of large areas with single species, insect pests increased, hence the interest in the life histories of the pests grew and gave rise to the celebrated work by _Ratzeburg_, “_Die Waldbverderber und Ihre Feinde_” (1841). A number of similar hand-books on insects and on other zoölogical subjects followed; the latest, a most complete work on insects, being still based on Ratzeburg’s work, is that of _Judeich and Nitzsche_, in two volumes (1895). Of course, the general works on forest protection always included chapters on forest entomology. The first of these text-books on forest protection was published by _Laurop_ (1811), and others by _Bechstein_, _Pfeil_, _Kauschinger_ and recently by _Hess_ (1896), and _Fürst_ (1889).

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_Knowledge of the soil_ was but poorly developed in the encyclopædic works of the earlier part of the period.

Not till Liebig’s epochmaking investigations was a scientific basis secured for the subject. Then became possible the improvements in the contents of such works as _Grebe_ (1886), _Senft_ (1888), and of _Gustav Heyer_, whose volume (_Lehrbuch der Forstlichen Bodenkunde und Klimatologie_, 1856), well records the state of knowledge at that time. But only since then has this field been worked with more scientific thoroughness by _Ebermayer_, _Schrœder_, _Weber_, _Wollny_, and by _Ramann_, whose volume on _Bodenkunde_ (1893) may be still considered the standard of the present day (newest edition, 1910).

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.

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