Читать книгу A Brief History of Forestry - B. E. Fernow - Страница 21

In addition to the restrictive measures and attempts at mere conservative lumbering without much thought of reproduction, there were as early as the 16th century silvicultural methods applied to secure or foster reproduction.

Owing to differences in local conditions and difference in necessities, this development varied greatly in various sections as to the time it took place. The Western and Middle country practiced as early as the 16th century what in the Eastern country did not appear until the 18th century. The forest ordinances, from which we derive our knowledge or inferences of these conditions, prescribed, to be sure, many things that probably were not really put into practice.

a. Natural regeneration was at first merely favored, without the adoption of any very positive measures to secure it, namely, by removing the cut wood within the year, so as to give young growth a chance of establishing itself, by removing the brush so as not to smother the young growth, by keeping out cattle from the young growth (Schonung).

If the selection method of lumbering, most generally practiced without much plan, did not produce any desirable result in reproduction, the clear cutting which was practiced without system where charcoal manufacturing or river driving invited to it, did even less so. In either case, besides the defective and damaged old stubs which were left in the logging, a poor aftergrowth of undesirable character remained, as is the case in the American woods on so many areas.

As early as 1524 and 1529, we have record of a conscious attempt to secure a reproduction by leaving ten to thirty seed trees per acre; but the result was disappointing, for this practice, being applied to the shallow-rooted spruce, produced the inevitable result, namely, the seed trees were thrown by the winds.

This experience led to the prescription (in 1565) in the Palatinate to leave, besides seed trees, parts of the other stand for protection against wind damage; later, wind protection was sought by leaving parcels standing on all four sides, giving rise to a checkerboard progress of fellings or a group system of reproduction, which by the middle of the 18th century had developed into the regular strip system, applied in Austria (1766) to fir and spruce, and in Prussia (1764) to pine. And this marginal seeding method remained for a long time the favorite method for the conifers.

To avoid long strips and distribute the fellings more conveniently, v. Berlepsch (in Kassel) recommended (in 1760) the cutting in echelons (curtain method, Kulissenhieb), which insured better seeding, but also increased danger from windfalls, and was never much practiced, the disadvantages of the method being shown up especially in the Prussian Forest Order of 1788.

In the first half of the 18th century it was recognized that the wind danger would be considerably reduced by making the fellings progress from East or Northeast to West. The conception of a regular, properly located felling series was first elaborated in the Harz mountains in 1745 by von Langen, who also accentuated the necessity of preserving a wind mantle on exposed situations. Both of these propositions reappear in the Prussian Order of 1780, according to which fellings are to proceed in a breadth of twenty to thirty-five rods from East to West.

The application of a nursetree method for conifers was proposed in 1787 by v. Burgsdorf (Prussia), a dark position (Dunkelschlag) and a regeneration period of seven years being advocated.

In broadleaved forest, besides the selection forest, the natural result of the sprouting capacity of the hardwood had led to a coppice method which was extensively relied upon for fuel production. This was rarely, however, a simple coppice, for, intentionally or unintentionally, some seedlings or sprouts would be allowed to grow on, leading to a composite forest and finally to a regular coppice with standards (1569, etc.), with an intentional holding over of the valuable oak and ash for standards. Probably, however, large areas of unconsciously produced composite forest exhibited sad pictures of branchy overwood with suppressed underwood of poor sprouts, injured by game and cattle—a scrubby growth, into which crept softwoods of birch and aspen. Attempts at pruning such scrub growths into shape on quite an extensive scale are on record.

The recognition that more wood per acre could be secured by lengthening the rotation of the coppice, which seems to have been mostly twelve years or less, led to twenty and thirty year turns and finally to fifty, sixty and even eighty year rotations or so-called polewood management (Brunswick, 1745), also called Hochwald (high forest).

A full description and working plan for such a forest to be managed in eighty year rotation, the city forest of Mainz in the Odenwald and Spessart mountains, dates from 1773, and this polewood forest management became quite general after the middle of the 18th century, but in the last half of the 19th century it was generally replaced by the true high forest management under nursetrees, the experiences with the natural reproduction of conifer forest having proved the advantages of this method.

The primitive beginnings of this so-called Femelschlag method (Compartment selection or shelterwood method) are found, in 1720, in Hesse Darmstadt, where Oberforstmeister von Minnigerode prescribed regular fellings progressing from north to south, in which all material down to polewood size (in selection or virgin forest) was to be removed, excepting only a number of clean boles, one every ten to twelve paces being left for seed and nursetrees. The good results in reproduction stimulated owners of adjoining estates to imitate the method (1737).

The observation that in beech forest the young crop needed protection and succeeded better when gradually freed from the shade of the seed trees, especially on south and west aspects where drought, frost and weeds are apt to injure it on sudden exposure, led to the elaboration of the principle of successive fellings.

In the ordinance of Hanau, as early as 1736, three grades of fellings were developed, the cutting for seed, the cutting for light, which was to begin when the young crop was knee-high, and the removal cutting when the crop was high.

This method spread rapidly and was further developed by the addition (in 1767) of a preparatory cutting, to secure a desirable seedbed, and by lengthening the period of regeneration and elaborating other detail, so that, by 1790, the principles of natural regeneration under nursetrees for beech forest were fully developed in Western Germany.

In other parts, hardwood forest management was but little developed. The Prussian Forest Ordinance of 1786 contented itself with forbidding the selection method, by declaring natural regeneration, as practiced in the pineries, not applicable; while the Austrian Ordinance of 1786 recognizes only clearing followed by planting as the general rule.

b. Artificial Reforestation. Although sporadic attempts at sowing and planting are on record as early as the beginning of the 14th century, extensive artificial reforestation did not begin until the middle of the 18th century, by which time planting methods were quite fully developed.

Among the hardwoods, the oak was the first to receive special attention. By the middle of the 16th century the forest ordinances gave quite explicit instructions for planting oak in the so-called Hutewald, a combination of pasture and tree growth such as is found to-day in the bluegrass region of Kentucky; the remnants of these poor pasture woods with their gnarly oaks have lasted into modern times.

In the forest ordinance of Brunswick (1598) orders are given to plant on felling areas: “every full farmer shall every year at the proper time set out ten young oaks, every half farmer five, every farm laborer three, well taken up with roots (wildlings), and plant them in the commons or openings at Martini (November) or Mitfasten (Easter) and cover them with thorn brush” (to protect them against cattle).

About that time it was, indeed, incumbent on every marker to sow annually five oaks, or plant several young seedlings for every tree cut and to tend them a few years; and the custom existed in the low country—afterwards (1700) introduced by law in Saxony—to plant in celebration of certain occurrences—a kind of arborday—especially to celebrate the marriage day; in order to be married the bridegroom had to prove that he had planted a certain number of oaks, which in Prussia (1719) had to be six, besides six fruit trees. The existence of this custom, now long forgotten, has given rise in the United States to the story that this is the method by which the German forest is maintained.

The method of collecting and keeping acorns over winter was well known in 1579, as is evidenced by the Hohenlohe Forest Ordinance, which advised fall sowing, but, if that did not prove successful, to prepare the ground in summer, leave it through the winter and sow in the spring.

While, in earlier times, sowing seems to have had the preference, at a later period planting was practiced, at first with wildlings, but as early as 1603 we find mention of oak nurseries.

The Prussian Order of 1720 ordered the foresters to plant oaks in the openings before Christmas, for which they were to be paid, if the trees were found alive after three years. The growing and culture of oak also interested Frederick the Great, who ordered its extension everywhere. Very explicit and correct rules for growing and transplanting them, and some to which we would not subscribe, were given in the books of the 18th century. Among the planting methods we find, in 1719 and again in 1776, one similar to the Manteuffel method of planting in mounds.

While oak culture was especially fostered in Northwestern Germany, the cultivation of conifers first received attention in the southwest, and in the same manner which was inaugurated by the Nuremberg seed dealer in 1368. A new idea, introduced in the Palatine Forest Ordinance (1565) and in the Bavarian Forest Ordinance (1568), was the prescription, to soak the seed before use and sow mixed with sawdust or sand, bringing the seed under with brush or iron rakes.

Carlowitz (1713) taught well the methods of collecting, extracting and keeping the seed, and even proposed seed tests. The seedbeds were to be made as for carrots, dense sowings to be thinned, and the thinnings transplanted into nursery rows, the seedbeds to be covered with moss and litter to protect them against heaving; he also discusses the question of cost. The adaptation of plant material to different sites—conifers where oaks are not suitable—was also understood (Bavarian Forest Ordinance, 1683).

As long as the old method of extracting the seed in hot stoves or ovens prevailed, conifer sowings gave but indifferent results.

In the pine forests of Prussia, during the second half of the 18th century, the method of sowing the cones on large waste and sand barrens, where the sun would make them release the seed, was practised, and before Brémontier had written his celebrated mémoire sur les dunes, sanddunes had been recovered with pine plantations in Germany in the manner which is still in vogue.

The planting of conifers came into practice much later, and then it was mostly done with wildlings. Opinions differing as to the value of sowing or planting, it was erroneously held until the 19th century that planting was less successful and too costly in comparison with the small harvest yield, which necessitated cheapness of operations. It was only towards the end of the 18th century that planting of pine was resorted to, but merely for repairing fail places in sowings and natural regeneration, and then with a ball of earth (1779), using a hollow spade—a costly method. The cost of a certain plantation made in 1751 is, however, reported as less than $3.00 per M., in 1770 as low as 70 cents per M. To cheapen the operations the labor was exchanged for wood, pasture or other materials or advantages.