BRITISH LITERATURE. Brown and Nisbet, The Forester, 6th edit., 1894, chapters xiii.-xv.; J. Laird Macgregor, Organisation and Valuation of Forests, 1883; J. Nisbet, The Theoretical Principles of Woodland Management, and the Measurement of Timber, published as a series of articles in the Land Agents' Record, 1901, and of which chaps. i. and ii. of the present work (pp. 221-336) form a 2nd, revised edit.; W. Schlich, Forest Management (vol. iii. Manual of Forestry), 2nd (issued as 3rd) edit., 1905. Part of the subject is treated of by T. Bright, The Principles and Practice of Timber Measuring and Valuing, 1899. THE THEORETICAL PRINCIPLES OF WOODLAND MANAGEMENT. 1. Matters to be considered in framing any Scheme of Management. 2. Essential requisites for the "normal condition" of the Growing-Stock or Capital in Wood. 3. Choice of the Sylvicultural Treatment. 4. Selection of the kind of Crop to be grown. 5. Fixing the Rotation with which the Timber-Crops should be worked. 6. Sylvicultural and Actuarial Considerations affecting the management of Woodlands. 7. Subdivision of the Woodlands into Working-Circles and Compartments. 8. Allocation of the Annual (or Periodic) Falls. 9. Different methods of fixing the Annual Fall. 10. The method of Management recommended for British Woodlands. 1. Matters to be considered in framing any Scheme of Management.— Like every other commercial enterprise, forestry requires a certain amount of capital. This consists partly of the land, and partly of the growing crops of wood. In highwoods worked with a long rotation, the capital required in the growing-stock of woods far exceeds the value of the soil. But even when such may not be the case, as in copses and coppices worked with a low rotation, forestry has the peculiarity, in comparison with most other commercial undertakings, that the commodity it produces (timber, fuel, bark, &c.) is exactly of the same description as part, and usually by far the greater part, of the capital which produces it. And this is apt to lead to confusion. Unless the annual falls of timber, &c., are carefully regulated, they may very easily be made so that, on the one hand, they are either actually eating into the capital in wood, or else, on the other hand, they fail to harvest all the annual increment. For we shall see that any given area of woodland requires a certain amount of capital in wood, proportionate to the area and the kind of crop, for its proper working on commercial principles; and no system of management can be economical which either diminishes this normal capital in 1 In addition to this invested capital, regular annual expenses are incurred in supervision, protection, rates and taxes; and for making actuarial calculations these may most conveniently be capitalised and regarded as representing an annual return from a capital sum equal to these yearly expenses divided by 0·0p, where p is the interest or rate per cent, which the business of forestry is supposed to yield locally. But this need not here be taken into account (see chap. v. p. 394.) wood or increases it unnecessarily by failing to utilise the amount of wood, &c., it annually produces. The amount of this produce can be expressed either in cubic contents or else in its monetary equivalent. The latter is the standard with regard to actuarial calculations for fixing the rotation of woods, and for comparing one method with another as to probable profit, while the former is the standard actually employed in carrying out practical operations based mainly on business principles. Woodland products consist of major produce (timber, fuel, bark) and minor produce (grazing, fruits, &c.), but, for all practical purposes in Britain, only the former need here be considered. It, however, may consist either of the mature fall or final yield of timber, &c., or of intermediate returns in the shape of thinnings-often very remunerative in themselves-rendered necessary for the proper tending of the still immature woods, so that the trees which will form the ultimate mature crop may be assisted in their development by the removal of all undesirable or badly-grown trees, or of dominated and suppressed stems interfering with their growth and expansion. The products of forestry differ essentially from those of agriculture by usually only maturing at a great age, in place of becoming marketable within the course of a few months or of a year, like most agricultural crops. Now, as wood is a bulky, heavy material, whose transport for long distances by land soon becomes unduly expensive, local markets can only be supplied, and the advantages of a constant demand secured, if the woodlands are managed so as to yield annual supplies of the given kinds and dimensions of wood in about equal quantity. If sales of wood are held only intermittently, at intervals of more than a year, it is improbable that the same advantages can be derived by the producer as if he could place more or less constant quantities of timber, &c., on the local market. To obtain the full advantages of a regularly sustained annual yield, however, it is of course necessary that the total area of the woods should be sufficiently large to admit of the annual falls being of a workable size; because the full advantages of systematic management become most apparent where large areas have to be dealt with, just as, in other commercial enterprises, wholesale production with a large amount of capital is usually more economical and more remunerative than business conducted on a smaller scale. Woods that are worked intermittently, as is most frequently the case throughout Britain, can be very simply managed. Any complex workingplan is unnecessary; all that is required is to ascertain (by means of average yield tables) from the present age and condition of the crops what their yield is likely to be when they are mature, and to determine when it may be most profitable to fell and regenerate or reproduce them, thinnings being meanwhile made only to the extent required by the trees intended to form the ultimate crop. Where there are only small woodland areas, this simple method is often best and most convenient for the landowner, while the small quantities of timber thus thrown intermittently on the local market are not likely to interfere with the normal conditions of supply, demand, and prices. In the management of extensive woodlands, however, it is desirable that the timber-crops should be so arranged and worked as to yield regular supplies of mature produce of about equal amount year by year. To attain this object it is therefore necessary that the woods should consist of a regular series of crops varying from each other either by one year only (as in annual falls of Pine, Larch, &c.) or else merely by such number of years as may be included in periodic falls for natural regeneration (Oak, Beech). It is not necessary-indeed, as we shall see later on, it is not desirable-that the series of falls should succeed each other consecutively like one long arithmetical progression; but they must be all represented within the area under management (working-circle), otherwise a regularly sustained annual fall or yield is impossible. 2. Essential requisites for the "normal condition" of the GrowingStock or Capital in Wood.-The main object of management on business principles is to bring the woodland area into a condition enabling it to yield. the largest profit consistent with due security for its future maintenancealthough any other scheme of management may of course be arranged so as best to attain any particular end desired by the proprietor. Where woodlands are primarily intended to be either ornamental or else game-coverts, as is frequently the case in Britain, they can of course not be worked on business principles. Otherwise, a working-plan aims at bringing the woods into a sort of ideal state or normal condition, so that they should exhibit (1) a normal succession of crops or regular series of woods of all ages, from the seedling up to the mature marketable tree, each age-class occupying an equal area, or at any rate an equally productive area; (2) a full stock or normal density of crop throughout the whole of each area;1 (3) a normal rate of 1 The normal density of crop varies, of course, with the species of tree and the nature of the soil and situation. Thus, on the classes of land most favourable to the development of each species, the normal density of pure crops throughout Germany is on the average (British Forest Trees, 1893, p. 43): : See also, however, the data given in Appendix III. (pp. 407-415) as to number And again, it has been shown that (Studies in Forestry, 1893, p. 188)—As regards the influence which the species of tree has on the extent to which thinnings are necessary, Schuberg (see Gayer's Waldbau, 1889, p. 550) found in the Black Forest that in 40- to 80-year-old crops, which had been regularly thinned, the following were the results on soil of average quality :— growth or normal increment on all the various crops, so that the growth annually made is fully proportionate to the quality of the soil; and (4) a normal distribution of the annual falls-that is to say, such a location of the various crops of different ages that the falls of mature timber may take place regularly within suitable sections of the forest, although not necessarily in close succession year by year. If these four conditions be provided, then one must have what can be more simply expressed as (1) a normal growingstock or capital in wood with a regular series of annual (or periodic) falls properly distributed over the working-circle, and (2) a normal increment or rate of growth fully proportionate to the quality of the soil, and producing equal returns in timber, &c., year by year. And these are naturally each dependent on the other for their possible attainment. This is, of course, merely an ideal standard which could only be achieved and maintained if the woods grew without being affected by mismanagement, fire, disease, insects, wind, &c. In comparison with intermittent utilisation, a system of managing extensive woods so that they shall yield a regularly sustained annual yield has certain obvious advantages and drawbacks. By offering regular annual supplies for sale it affords the best opportunity for securing, utilising, and maintaining the local market; the constant employment afforded to woodmen in felling, thinning, and planting makes labour cheaper and more efficient than is otherwise possible; and the woods are made to yield a regular income not subject to inconvenient variation from year to year. No available market can be utilised to the best advantage if the quantity of wood offered for sale is large one year, small the next, altogether wanting a third year, and so on irregularly. Its drawbacks are that, in order to try to attain the normal series and distribution of annual falls, the crops now on the ground have sometimes either to be felled before they have reached their full maturity, or else must be allowed to stand after the most profitable time for felling has been passed; while at the same time the striving after regularity precludes advantage being taken of specially favourable prices in any one year to make heavier falls of timber than usual. But on the whole, and certainly where large areas of woodlands are in question, the best system of management will usually be that which aims at providing a regularly sustained annual yield. The normal Growing-Stock, or Capital in Wood required for the proper management of any given working-circle or compact block of woodlands, consists in the total sum of the crops growing on all the various annual falls of normal size, age, and distribution. It is annually diminished by the normal yield forming each year's fall, which is, at the same time, the embodiment of the normal increment throughout the whole term of the rotation of the crop, and also equals in amount the growth for one year on all the annual falls forming the working-circle. But this loss is each year made good by the normal increment accruing throughout all the crops of different ages, from the seedling to the mature tree; hence the current capital required in the production of timber is a constant quantity if the average of each year be taken. Apart from the temporary variation from the average of capital in wood shown in autumn and in spring, the normal growing-stock required for any given working-circle is dependent (1) on the length of the rotation in which the woods are worked, and with which it rises and falls more or less proportionately, and (2) on the normal increment or rate of growth proportionate to the quality of the soil. And of course any circumstances affecting the increment, such as the kind of crop grown, the system of management, the quality of the soil and situation, &c., must also exercise direct influence on the amount of capital which should be provided and can best be utilised in timber-production. |