Forestry, like any other kindred industry, tries to ascertain the amount and quality of the yield obtainable with a view to finding out the most practical mode of working. T h e tastings undertaken to this end are — over and above a rough estimate — mainly based on measurements of the trees and technological experiments, although certain a u t h o r s — among whom ADOLF DANHELOVSKY, J. BEAUVERIE, and V. EKMAN of late have obtained a prominent place — from a more practical, mercantile point of view have made investigations into the productions.
Technological and analytical probings inform us of t h e mecha- nical, physical, and chemical qualities of the wood. In the terminology of foresters the idea of »quality« was once nearly synonymous with strength and durability as far as timber was concerned, and heating power in the case of fire-wood. As all these qualities sustain a certain proportion to the specific gravity of dry wood, the next step was to consider this — or rather the ligneous substance contained in a piece of wood — t h e standard of quality (ROBERT HARTIG). In more recent times the tendency has been to build on the anatomical structure: a comparison between spring-wood and summer-wood, the proportion of cavity to thickness of fibre; that is to say the magnifying glass and the microscope take the place of the scale and the xylometer.
338 [148]
Measurements and gauging of accretion, together with an estimate of the age of the trees, show us the amount of production of wood as well as dimensions of the trees produced, and these are divided according to size, shape, and structure into different classes, the lines often being drawn mainly with a view to the account and general control of t h e work.
While t h e trees are in growth, it is generally the surface only t h a t the forester is able to examine, and when they have been felled and worked, it is but a few cuts and lengths he gets to see of t h e inside. Experience and practise, however, together with his know- ledge of the structure of the wood, enable him to judge of the inner qualities from the outer shape and configuration, and in this respect he is assisted by his customers, w h o at least emphasize flaws and de- fects, while their praise finds vent in greater demand and better prices.
The manufacturer, to whom wood is a raw material, must above all make sure to get the most out of it in t h e form of manufactured articles; in his estimation the technical qualities will usually be of only secondarj' importance. The strict classification into assortments according to dimensions of the wood and the strong prominence given to the mere bulk of each class offered for sale have tempted the forester to lay the chief stress on formal compliance with regulations for assortments, and not on the more essential consideration of what is in demand. It is the consumption now and in the future that is to direct felling, cutting and classification of the trees as well as cultiva- tion and tending of woods; the accounts are to show the character of the consumption, but practical forestry cannot be guided by it.
The experiments and tastings, discussed above, are to show how dimensions, shape and structure — or possibly defect in structure — affect the amount and quality of the yield. To this end raw material
— trunks and piled timber — is sifted much more closely than other- wise, and the yield obtained is divided into its separate parts.
In practical forestry as also in the timber trade, stands and even regular forests often ought to be classified according to what cha- racterizes the wood for some large area, indicating its particular use, t h e present state of the market always being taken into consideration.
In the long run it will be best for all parties concerned that each seller seeks a market for his goods where their good qualities are duly appreciated and the inferior ones tolerated; on the other hand, saw-mills and wood-goods factories ought to be set up in districts that can deliver a constant supply of suitable raw materials.
The object being to find out to what extent wood can be prac- tically utilized, it is generally used in the ordinary way, even though it might occasionally be differently emploj'ed; no other goods, or goods in other quantities, are manufactured than w h a t is sanctioned by practise, when the wood in a certain district was to be used at all.
The t r u n k s examined are not classified according to length and diameter only. As the size of the knots, the decrease of diameter
and several other things change from root to top, a classification ac- cording to sections of height is also often made, so as to distinguish the but from a series of consecutive sections, each at a certain di- stance from the ground. In this way we learn to understand how distance between the plants as well as cutting and pruning affect the amount and quality of the yield.
It is obvious t h a t these tastings to some extent may be of assi- stance to the owners of saw-mills and similar factories, especially through particulars as to quantity of saw-dust, chips, etc. But this is not the main thing as far as the w o r k is concerned; t h e o b j e c t is s p e c i a l ^7 t o c o n t r i b u t e t o t h e c o n s t r u c t i o n of a m o r e s o l i d b a s i s f o r t h e p r o d u c t i o n of t i m b e r , r a n g i n g f r o m t h e v e r y s t a r t of t h e w o r k — s e l e c t i o n of s p e c i e s a n d c h o i c e of s e e d — t o t h e f i n a l p r e p a r a t i o n i n t h e f o r e s t .
Of the many experiments and tastings the following may be men- tioned, the n u m b e r s enclosed in brackets referring to pages: [1] — [78] are found in vol. I, [79] — [109] in vol. II, and [110] — [147] in vol. V of »Det forstlige Forsøgsvæsen i Danmark«. An abstract is found in the a u t h o r ' s text book: T r æ og andre Skovprodukter, Kø- benhavn 1911—16, chapter XVI.
1. S t a v e s m a d e of b e e c h - w o o d [I, 138]. The yield increas- es in proportion to diameter up to 10 Danish inches (1 Dan. in. = 1.0297 Eng. in.; 1 Dan. Alen = 2 feet = 24 in.; 1 m = 3.18620 Dan. feet), after that decreases, but reaches a new maximum at 16 in. Even wood of 5—6 in. in diameter may yield a considerable supply of staves, but these are always n a r r o w (2'A in.). At only 8—10 in. nearly the same amount of first class staves is obtained as from the class of 14—16 in.
Classifications according to shape and purity, of qualities a, b, and ct
prove that the a m o u n t of inferior staves increases from a to c, but this last quality gives 30 per cent less than a of good wide staves.
How t h e amount of stave-wood decreases in proportion to the di- stance from the ground may be learned from a special investigation:
Height sections in beech stands (Höhenschichten in Buchenbestän- den), vol. IV, page 1—23. As to saw-dust, varying from 10 to 14 per cent, a good quality of wood gives m o r e than an inferior kind, and thin wood more than thick.
2. S h o v e l - h a n d l e s m a d e of b e e c h - w o o d b u t s [I, 172].
Two trunks, 12 feet long, were divided into 3 sections, each of which yielding 9 planks. F r o m root to top t h e n u m b e r of handles decreas- ed as follows: 51, 43, 43 per cent, while of the inferior turner's wood 4, 8, and 4 per cent was the result. T h e total amount of partly ma- nufactured articles was 55, 51, and 47 per cent. Plank no. 5 being next to the pith, 1 and 9 the outer parts, t h e yield would be as follows;
For planks n o s . . . 5 4 + 6 3 + 7 2 + 8 1 + 9 Handles, pet 40 41 54 41 0 Turner's wood, pet. 3 6 4 7 22 In all, pet 43 47 58 48 22
340 [150]
The maximum of yield is thus far from the pith, planks 3 + 7 , although narrow and sloping at the sides, but knotless and of regu- lar structure.
3. B o t t o m s f o r s h o e s m a d e of b e e c h - w o o d b u t s [I, 164]. (Shoes made of wooden bottoms and leather vamps are to be distinguished from the ordinary wooden shoe, having a wooden toe and a block of the same height as the heel, under the ball of the foot). 18 trunks, diameter 24—40 cm., were divided into 3 sections according to diameter,' and each of these into 3 classes according to quality. The amount of bottoms is 8—12 pet., leaving some inferior timber. The loss on the small buts consists mainly in bottoms for small foot-wear. The bigger the but, the greater amount of large bot- toms for grown-up people.
4. S p o k e s m a d e of o a k b u t s [I, 184], 16 trunks, averaging 18 feet in length, were cut into spokes, 2 feet long, after having been divided into 3 sections: root trundle, trundle nos. 2—5, and trundles nos. 6 and upwards. In each section trundles of more and less than 25 cm were kept apart, and the two upper ones were divided into 3 qualities: a, b, and c. The yield was as follows:
S p o k e s , pet., in t h e t r u n d l e s S p o k e s , p e t . q u a l i t y I.
II.
III.
The top section yielded a n u m b e r of seconds, and they were mostly small. The proportion between firsts and seconds does not vary much in the same class divided according to width and quality;
t h e loss in section III is due to t h e fact that it contains a propor- tionately large amount of inferior wood. The knotless part of the heart-wood of the trunk forms a shell, the thickness of which decreas- es greatly towards the t o p ; the knott5r part has the shape of an in- verted cone.
5. H a n d l e s f o r i m p l e m e n t s , m a d e of a s h b u t s fl, 196].
62 small buts, 86—180 cm long, were sorted into 3 classes according to diameter, and these again according to quality into classes a, b, and c. The buts were cut into square poles, IVBXIVS in., to be turned into handles for implements. The yield in meter per m3 was as follows:
D i a m e t e r a n d q u a l i t y of t h e b u t :
™ s ?f - d e r 30 cm
m per m8 a b c
Firsts 192 77 32 Seconds ... 36 133 79
under 25 cm Root T r u n d l e . . 35
i a. 44 Trundles 2 - 5 : . 1 b. 40
I c. 0 r a. 40 Trundles 6 & ) A qe
u p w a r d s , . . . | c 2 g
over 25 cm 48
50 \
4 7
37 J 40 i 44 [ 37 >
firsts 78 63
42
seconds 22 37
58
3 0 - 3 5 a b 202 109
31 83 cm
c 106
69
over a 226
19 35 cm
b 165
51 In all 228 210 111 233 192 175 245 216
It is evident that the quality of the buts is fully as important as the dimensions; first class buts of less than 30 cm yield better re- sults than seconds of more than 35 cm, and first class buts yield a m u c h larger amount of first class poles, but fewer second class ones, than buts of an inferior quality.
.6. B o a r d s m a d e of s p r u c e b u t s [V, 302]. 80 buts, 12 ft.
long, 12—26 cm in diameter, were cut into boards, after having been divided into 7 classes according to diameter. The yield of unassorted b o a r d s increased but little in proportion to the diameter of the buts, but the thick buts yielded fewer boards of an inferior quality and many more good squared ones. The buts of each class according to diameter were subdivided into classes a and b according to qua- lity, the more or less approximately cylindric shape being taken into account; the following average results accrued:
a. Squared boards 49.0 pet., inferior boards 10.4 pet., in all 59.4 pet.
b. — — 44.6 — — — 10.4 — — 55.0 — Of the entire lot of buts the results were: 54.2 pet. boards, 31.1 pet. waste products, 14.7 pet. saw-dust.
7. H e i g h t s e c t i o n s of s p r u c e t r u n k s [V, 311]. 15 spruce trunks, 48 ft. long, were divided into 4 height sections, so as to yield 15 buts of each. The amount of unassorted boards decreases but little in proportion to height, but the amount of squared boards from the 2 nd section was twice as large as that of the 4 th. By sorting the squared boards according to quality, the inferior goods from the four sections w e r e found in the following proportion: 35, 82, 78, 87 pet.
The value of the boards produced shows the following distribution according to the four sections: 36.1, 28.8, 22.2, 12.9 pet.
8. S t r a i g h t a n d c r o o k e d b u t s f r o m s p r u c e [V, 318].
In square-seeds the trees that attain dimensions for timber will often have a curve at the bottom (fig. 1, page 320). The curvature was 6.5 cm. The aggregate amount of boards is not reduced by this defect, but in t h e squared boards the proportion between crooked and straight buts is 3 : 4 , and of these there were 73 and 10 pet.
respectively of an inferior quality. The loss sustained by this culti- vation may t h u s be very considerable.
9. W o o d - w o o l f r o m s p r u c e [II, 343]. A quantity of barked spruce was sorted according to dimension yielding the following a m o u n t of wood-wool:
Diameter: 67* 8 7« 107s' 127» 147» 167» 187» 207» 227» cm.
Wood-wool: 356 393 411 426 423 413 423 405 kg p e r m8. Cheap and thin wood, accordingly, yields the same amount as the thick, which thus more profitably may be used for boards and similar material. The Danish export of eggs demands a large con- sumption of wood-wool, and t h u s earlier thinnings may be profitably utilized.
Det forstlige Forsøgsvæsen. V. 20. November 1920. 2 5
342 [152]
10. C e l l u l o s e f r o m s p r u c e [II, 351]. A parcel of spruce was sorted according to dimensions yielding the following quantities of air-dried cellulose:
Wood from stem Wood from top Diameter: 10—15 15—20 20—25 10—15 15—25 cm
Cellulose: 170.6 177.5 185.6 163.2 170.5 kg per n r . As with the previous experiment the advantage of using the thin, cheap wood is evident. At present Denmark has no cellulose fac- tory, whereas some wood-pulp is being manufactured.
A comparison between examples nos. 1—5 on the one hand and no. 6—10 on the other shows that a rational sorting of wood of foliferous trees is far more complex than the sorting of spruce.
1 1 . P r o d u c t i o n of p l a n e d , t o n g u e d a n d g r o o v e d b o a r d s [V, 321]. By the process of planing on all four sides, spruce boards, l1/* in. thick, lost 22—23 pet. in weight and bulk. This, I think, is more than generally supposed.
12. T h i c k n e s s of b l a d e a n d a m o u n t of s a w - d u s t [V, 330]. By cutting laths from spruce buts, using t h r e e different cir- cular saws, the following amount of saw-dust was obtained:
Thickness of blade, millimeter: 3.6 2.7 2.0 Amount af saw-dust, pet.: 22.3 18.4 12.3
Experiments like those mentioned above, it is true, are really simplicity itself; they are neither applied natural science nor applied economics. But they demand considerable circumspection, perseve- rance, and exactness on the part of the one who is in charge of the work; when same is to be kept within reasonable bounds, it must be planned in such a way that the experiment may settle the que- stion asked without demanding more attention than absolutely neces- sary; and in formulating the problem to be solved in each case some knowledge is requisite as to how Danish timber is to be worked and utilized, together with an understanding of the growth of trees and how they are to be sorted.
A. OPPERMANN: Højdelag i Bøgebevoksninger (Höhenschichten in Buchenbeständen). — A. OPPERMANN: Ædelgranens Vækst paa Bornholm (Le sapin pectiné å l'ile de Bornholm). — A.
OPPERMANN: Den grønne Douglasies Vækst i D a n m a r k (The Douglas Fir in Denmark). — L. A. HAUCH og F . KØLPIN RAVN:
Egens Meldug (L'oi'dum du chéne). — A. OPPERMANN: E n Gran- bevoksning paa god, midtjydsk Hedebund (Ein Fichtenbestand auf gutem Heideboden im mittleren Jutland). — A. OPPERMANN:
Overvintring af Agern (Überwinterung von Eicheln). — JOHS.
H E L M S : Iagttagelser over Rødgranens og Ædelgranens 3'dre Form (Beobachtungen über die äussere Form der Fichte u n d Weiss- tanne). — A. OPPERMANN: Elleve Prøveflader i Bøgeskov (Elf Probeflächen in Rotbuchenbeständen). — J O H S . H E L M S : Forsøg med Lystræer paa Feldborg Skovdistrikt, II (Versuche mit Licht- hölzern auf Heideboden). — L. A. HAUCH: Proveniensforsøg med Eg (Proveniensversuche mit Eiche). — F R . W E I S og C. H. BORNE- BUSCH : Om Azotobacters Forekomst i danske Skove, samt om Azotobacterprøvens Betydning for Bestemmelsen af Skovjorders Kalktrang (Über das Vorkommen des Azotobacter in dänischen Wäldern, sowie über die Bedeutung der Azotobacterprobe für die Bestimmung des Kalkbedürfnisses der Waldböden). — A.
OPPERMANN: God dansk Bøgeskov, belyst ved tre Tilvækst- oversigter (Gute dänische Buchenwälder, in drei Ertragstafeln dargestellt). — L. A. HAUCH: Udhugning i unge Egebevoksnin- ger, II (Durchforstung junger Eichenbestände, II). — S. M. STORM : Fremmede Naaletræer paa Søllestedgaard (Foreign coniferous trees of Søllestedgaard estate). — A. OPPERMANN: Den grønne Douglasies Vækst i Danmark, II (The Douglas Fir in Denmark, II).
— A. OPPERMANN: Septemberskovet Brænde (Austrocknung von im Herbst gefälltem Brennholz). — Forsøgsvæsenets Ordning og Ledelse (Das forstliche Versuchswesen in Dänemark. — The Danish Experimental Forestry Service. — Station des Recherches forestiéres du Danemark).
F E M T E BIND, lsté—3dje Hæfte, indeholder:
A. OPPERMANN: Bjærgfyr i Danmark paa Flyvesand og hævet Havbund (Die Bergkiefer in Dänemark auf Flugsand u n d ehe- maligem Meeresboden). — K. H. MUNDT: Den enstammede franske Bjærgfyr i Danmark (Le pin de montagne francais en Danemark). — L. A. HAUCH : Nattefrostens Virkning i ung Bøge- skov, II (Die Wirkung des Spätfrostes in jungen Buchenwald-
ungen, II). — G. B R Ü E L : Jordbunden i Grib Skov (Der Boden in Grib Skov bei Hillerød). — AXEL S. SABROE: Skovtræer i det nordlige J a p a n (Forest trees in Northern Japan). — K. MØRK-
HANSEN: C. H. Schröders Udhugning i Bøg, II (Eine Unter- suchung der Buchendurchforstung C. H. Schröders). — A . O P P E R - MANN: Sommerfældning i Bøgeskov (Sommerfällung von Buchen- brennholz). — L. A. HAUCH: Proveniensforsøg med Eg, II (Ex- periments regarding proveniences of oak). — J O H S . HELMS og PAUL W E G G E : Prikleforsøg paa Silkeborg og Vemmetofte Skov- distrikter (Versuche über Verschuhmg von Fichte und Tanne)