THE INFLUENCE OF SITE FACTORS ON WOOD DENSITY AND MOISTURE CONTENT OF BEECH IN THE UKRAINIAN CARPATHIANS

Transcription

1 1 THE INFLUENCE OF SITE FACTORS ON WOOD DENSITY AND MOISTURE CONTENT OF BEECH IN THE UKRAINIAN CARPATHIANS Dr. Ivan Sopushynskyy*, Docent, Dr. Ivan Vintoniv, Departent of Botany, Wood Science and Non Wood Forest Products Ukrainian State University of Forestry and Wood Technology Gen. Chuprynka 13, Lviv 7857, Ukraine Tel.: and Fax.: / *an award holder of the NATO Science Fellowships, Forest Research Institute, Warsaw, Poland Prof. Dr. Alfred Teischinger Institute of Wood Science and Technology University of Natural Resources and Applied Life Sciences A-118 Vienna, Gregor-Mendel-Strasse 33 Austria Dr. Roan Michalak Departent of Forest Manageent Planning and Monitoring Forest Research Institute ul. Bitwy Warszawskiej 192 r. nr Warszawa, Poland E-ail: ABSTRACT In the article the specific use of ethods by the investigation of wood density were analyzed in the context of their iportance for forest and wood technology branches as well as for carbon inventory and onitoring in the Ukraine. The influence of site factors on wood density and wood oisture of beech (Fagus sylvatica L.) in Ukrainian Carpathians was investigated. According to the research results the environental influence on wood tissues of European beech has a significant effect on the technical value of tiber. Wood density and oisture content are two variables that are strongly correlated with forest site types or altitude.

2 2 INTRODUCTION The perforance of wood as a raw aterial is characterized by different properties, which were fored by the natural conditions in growing trees. Wood density, which varies with tree species, growth conditions, biotope etc., - fors an integral coponent of tree breeding progras and the ain characteristics of wood quality. Since the quality of wood is the result of a long process where genetic dispositions of the tree interact with environental requireents (Kucera 1994), the tree growth rate affects not only the foration of wood but also its physical properties (Poluboyarynov 1976; Senft et al. 1985; Keith 1988). By analyses of wood properties, little is known about how the site types influence the wood density of the ain industrial wood species in Ukraine (Vintoniv, Sopushynskyy 1996). There is also a within-tree variability (along ste height as well as radius) which was firstly docuented for European wood species by Trendelenburg (1936) and has been extended to further species and forest regions in the course of the tie (Poluboyarynov 1976; Uholev 1982; Walker 1993). There is a close correlation between the site indexes deterined as richness and oisture content of soil and the density of wood (Kollann, Cote 1968; Krzysik 1978; Splawa-Neyan 1994; Ketterings, Coe, Noordwijk, etc. 21]. The prediction of wood density plays an iportant role to estiate an above-ground tree bioass correctly. The estiation of above-ground tree bioass is an essential aspect of studies of carbon stocks, deforestations and carbon sequestration on the global carbon balance. A coon ethod for estiating carbon stocks in living bioass in forest land is the use of equations which relate 3 1 carbon stocks (C ) to the bioass of individual trees, such as volue ( V, ha ), basic wood density ( ρ, kg ), bioass expansion factor for conversion of volue to above ground tree 1 bioass ( BEF ), root-shoot ratio ( R ) and carbon fraction of dry atter ( CF, C ( kg d..) ) (IPCC 2 23): C = [ V ρ BEF2 ] (1 + R) CF, (1) The ajority of research on wood properties was done on ature trees at the age of 8 years and ore. It is also iportant to study the wood properties of younger trees in view of their present and future use. The wood, like any organic aterials depend on environent and its use as a construction aterial deands a precise knowledge of wood properties which are ainly based on density. The ai of this paper is to analyze the specific use of ethods by the investigation of wood density for forest and wood technology branches as well as for carbon inventory and onitoring in the Ukraine and to study the influence of the growing conditions of the southwestern egaslope of the Carpathians on oisture content and basic wood density of beech (Fagus sylvatica L.). METHODS The relationship between the density at a given oisture content and the density of ovendry wood is of the great technical iportance (Kollann, Cote 1968; Poluboyarynov 1976; Krzysik 1978). For ost species the literature thus gives a range with low, ediu and high values. As one will note, there is no standardization of the oisture content of the (air dry, wet, green) wood in the densities reported, and soe conversions ay be needed. A theoretically correct solution is not difficult to achieve. The share of oisture content in green wood can be expressed by the following equation: +.. w. 2O ρ o d H green =, (1) Vax where ρ - density of green wood, green kg ; - ovendry weight of the wood, kg ; o. d. w. 3 H 2 - weight of the water, O kg ; V - the volue of the green wood ( ax W > 3% ),. Whereas in wood physics density is generally based on both weight and volue at the sae oisture content, in forest carbon inventory research, tree iproveent progras etc. it is ore correct to deterine the density as ovendry weight and volue at a specified oisture content (Kollann, Cote 1968; Walker 1993). By calculating the basic density (Eq. 2), the

3 3 ter basic ephasizes that both paraeters easured, the ovendry ass and the green (swollen) volue, have constant and reproducible values. Basic density deterines the ratio of the weight of the oven-dry wood ( ) and the volue of green wood ( V green V ax ). ρ b =, (2) Vgreen The deterination of the wood density at a given oisture content (e.g. ρ = V ) according to the present industrial standard of Ukraine creates difficulties in forest research (Standard (ГОСТ) ; Poluboyarynov 1976). During the storage of logs in the forest, their oisture content decreases, influenced by different factors, such as season of felling, place and duration of storage and weather conditions. Hence as industry is ore concerned with the aount of woody tissues in a given volue of tiber, air-dry wood density ( ρ often preferred. ), (Eq. 3) is ρ...15 =, (3) V...15 This figure ay not only be deterined easily, since the volue ( V ) is easurable by the displaceent of water without any error but it is also inforative fro the point of view of forestry (Kollann, Cote 1968; Poluboyarynov 1976) and plays an iportant role for carbon inventory and onitoring. In practical application the density of ρ, green ρ and ρ are iportant b with respect to shipping weight and calculation of round wood volue (Jänes 21). Basic density is a very iportant pulpwood paraeter, influencing any aspects of the pulp and paper industry including freight costs, chipping properties, pulp yield per unit ass of wood, paper quality and easureent of carbon stock (Balodis 198; IPCC 23). Since density is influenced by the oisture content of the wood, coparisons of density figures can only be ade at the sae oisture content. As known, the wood density is influenced by the site type and the age. The oisture content of wood depends on the biotope, season, altitude and changes within the height and diaeter of trees (Trendelenburg 1939; Kollann, Cote 1968; Poluboyarynov 1976; Krzysik 1978; Biley, Vintoniv 1983). The estiation of green density is not reproducible and should therefore be avoided. The correct deterination of oisture content is therefore iportant. The oisture content ( abs W ) is the ass of water ( w ) contained in the wood, expressed as a ratio to the ass of the oven-dry wood ( ) on a percentage basis and calculated as follows: w W = abs 1%, (4) The oven drying ethod was usually used to deterine wood oisture content (Standard (ГОСТ) ). STUDY SITES All data were collected in ixed forest stands in forest copanies of Khust, Volovets and Ust-Chorna which is located in western Ukraine in the region Zakarpatska in August and Septeber 1997 (Tab. 1). This study was conducted on 1 observation plots involving the steady vertical distribution of beech wood at the following altitude: 25, 4, , 75, 85, 9, 1, 11, 5. The site types were deterined by the forest typology of Herushynskyy (1996) for Ukrainian Carpathians as richness of soil and soil oisture. Each observation plot coprises a group of ore than 1 beech trees. The square plot area was.25 ha. All growing trees with a diaeter at breast height of 7 c or ore located within these plots were nubered. In each observation plot bioetric features of all nubered trees were easured, that is breast diaeters (1.3 above ground) and the height of trees proportionally to the nuber of trees in adopted (2 c) thickness classes. The obtained characteristics of thickness-height of trees allowed, based on the dendroetric ethod (Standard (ГОСТ) ), to define three thickness classes with the axiu nuber of trees. According to the diensions of thickness classes it would be looked for the odel trees and then they were cut down.

4 4 Table 1. Forest and estiated features of observation plots of beech stands and odel trees *Fagus sylvatica L.- FAS; Carpinus betula L. CAB; Abies alba L. ABA; Picea abies Karst. PIA; Acer pseudoplatanus L. ACP; Quercus robur L. QUR; Fraxinus excelsior L. FRE; + defined as >5% ** D 2 - fresh broadleave (beech) forest; D3 - wet broadleave (beech) forest; C3 - wet ixed broadleave (beech) forest. 29 trees contributed to the deterination of basic density and oisture content of beech wood. Sapling trees was achieved by using the destructive (discs) ethod. The easureents of variables were done at breast height, 1/3 of length of bole and 1 before the beginning of tree crown to represent the whole tree (Fig 1). Fig. 1 Scheatic illustration of the sapling procedure - cutting of discs The discs were cut into three segents: juvenile wood where heart-wood foration ay be initiated, year rings 5-2 fro the pith, transition wood, containing approxiately 1-4 year rings, and ature wood, year rings 2-6 fro the bark. The green volue of the segents was easured by water displaceent ethod. With the oven drying ethod the oven-dry ass was easured after 24 h at 13 ± 2 o C. The initial weighing of each saple was ade as quickly as possible after it had been cut to the nearest.1g on a precision balance (Standard (ГОСТ) ; Standard (ГОСТ) ). Errors, due to unavoidable delay before weighing, were iniised by placing the saple in polythene bags iediately after cutting. The following variables were included in the statistical analyses: wood basic density (kilogras per cubic etre), wood oisture content (percent) and altitude (eter) for every observation plot. The statistical analyses was based on procedure SPSS 8. - One-Way ANOVA (Analysis of Variance Analysis of Variance) to produce a one-way analysis of variance for a quantitative dependent variable by a single factor (independent) variable (Brosius 1998). For the analysis of variance a t-test was applied which looks at the difference in eans of a continuous variable between two groups. Null hypothesis has no difference in the ean values and the alternative hypothesis has a difference in the ean values (significant at <.5). RESULTS AND DISCUSSION Moisture content The oisture content of "green", i.e. freshly cut wood varies within the diaeter, the tree height (Sachsse 1971). Statistical characteristics of wood oisture content of beech presented in Table 2, there is a clear relation between altitude and oisture content of beech wood. The differences in variability of ean values of the wood oisture content between 25 and 5 above sea level were evident or significant (<.5). According to the statistical analysis within

5 5 the database of oisture content of ten site types, three categories of altitude were grouped (Table 2). Table 2. Statistical analysis of wood oisture content of beech Altitude, Site type N, units M ±, % V,% P,% under 6 D2-fresh broadleave (beech) forest ± D3 -wet broadleave (beech) forest ±, above 95 C3 -wet ixed broadleave (beech) forest ±, The average wood oisture content appears to be the highest at an altitude of The research results show that the environent has a strong effect on wood oisture content of European beech in Ukrainian Carpathians. Wood density According to the statistical analysis within the database of wood density of ten site types, three categories of altitude were grouped. The wood at an altitude above 95 is showing the lowest density (53 kg ). Assuing the value obtained for wood at an altitude of 6-95 ature as 1 % and a coparison to values obtained for wood at the altitude above 95 and under 6 indicates clearly that those tissues have a lower density of 5.9 to 1.5 % (Tab. 3). Table 3. Statistical analysis of basic wood density Altitude, Site type N, units M ±, kg V,% P,% under 6 D2-fresh broadleave (beech) forest ± D3 -wet broadleave (beech) forest ± above 95 C3 -wet ixed broadleave (beech) forest 4 53± While the altitude was increasing to 95 above sea level, the quality of forest site types and basic density of beech wood increased accordingly. The density of the site types higher than 95 above sea level was generally low, while the quality of forest site types decreased. The variation of wood density is likely to be the ajor source of uncertainty. However, calibrations by collecting density data for each site plays an iportant role and requires the developent of a ethod for estiating above-ground tree bioass by the use of equations which relate the bioass of individual trees to an easily obtainable non-destructive easureent, such as diaeter, height and age. The results show that the altitude or forest site types appeared to be a oderate to good predictor of the wood density. CONCLUSIONS The results show that the slope of ountain (sea level) is a natural laboratory to investigate the wood properties which were fored by the different natural conditions in growing trees. Wood density and oisture content are two variables that are strongly correlated with the environent as well as forest site types or altitude. The environental influence on wood tissues of European beech has a significant effect on the technical value of tiber, characterized by wood density and oisture content. Wood density at the altitudes of 6-95 was higher than at altitudes under 6 and above 95. The differences between these variables were 5.9 % and 1.5 % respectively. The research results show that the values of basic density vary between forest site types or altitude and support the following hypothesis for forestry and forest carbon inventory: - the study of the air-dry wood density ( ρ...15 = ) is technically of greater iportance V...15 than the wood density ( ρ = V ) according to the present standard of Ukraine; - the developent of a rapid ethod for estiating the basic density of standing trees is an iportant task within the forest carbon inventory.

6 6 REFERENCES 1. Balodis, V. 198: Assessent of the pulpwood quality of forest resources. CSIRO Div. Che. Technol. Res. Rev: Biley V.P., Vintoniv I.S Wood oisture content of European beech in Ukrainian Mountainous. Forest Journal. 1. Arkhangelsk: Brosius, F SSPS 8.. Professionelle Statistik unter Windows. - Bonn: MITP-Verlag GbH, 11 pp. 4. Herushynskyy Z.Yu. 1998: Forest Typology of Ukrainian Carpathians: Textbook. Lviv: Piraida, 28 pp. 5. IPCC. 23: Good Practice Guidance for Land Use, Land-Use Change and Forestry. National Greenhouse Gas Inventories Prograe. Published by the Institute for Global Environental Strategies, 564 pp. 6. Jänes J. 21: Calculation of roundwood volue through its density. Baltic For. Vol. 7 (2): Keith C.T., Chauret G Basic wood properties of European larch fro fast-growth plantations in eastern Canada. Can.J.For.Res. 18: Ketterings Q.M., Coe R., Noordwijk M. etc. 21: Reducing uncertainty in the use of alloetric bioass equations for predicting above-ground tree bioass in ixed secondary forests // Forest Ecology and Manageent 146: Kollann, F. F. P., W. A. Cote, Jr. 1968: Principles of wood science and technology. I. Solid wood. Springer-Verlag, 591 pp. 1. Krzysik F. 1978: Wood Science. Warsaw, 653 pp. 11. Kucera B A hypothesis relating current annual height increent to juvenile wood foration in Norway spruce. Wood Fiber Sci. 26 (1): Poluboyarynov O.I. 1976: Wood density. М.: Forest industry, 16 pp. 13. Sachsse H Der Feuchtegehalt von Buchen-Indusrieholz // Holz als Roh- und Werkstoff. 2: Standard (ГОСТ) : Wood. Method of wood density deterination. М.: Publisher of Standards, 6 pp. 15. Standard (ГОСТ) : Wood. Method of selection of odel trees and saplings for the deterination of physical and echanical properties of wood in forest. М.: Publisher of Standards, 6 pp. 16. Standard (ГОСТ) : Wood. Method of wood oisture content deterination. М.: Publisher of Standards, 4 pp. 17. Senft J.F., Bendtsen B.A., Galligan W.L Weak wood. J.For. 83: Standard (ГОСТ) : Wood. Method of wood oisture deterination. М.: Publisher of Standards, 4 pp. 19. Trendelenburg, R Das Holz als Rohstoff. J. F. Lehanns Verlag, München: Uholev B.N. 1986: Wood Science and Wood Product. Text book. М.: Forest industry, 368 pp. 21. Vintoniv I., Sopushynskyy I. 1996: Probles of woody species breeding on wood quality at forestry sector. Scientific agazine. Scientific technical collection 5: Forestry Science. Lviv: UkrSUFWT Publisher: Walker, J. C. F Priary wood processing: Principles and practice. 1st ed., Chapan and Hall, 595pp.