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V. Tanušev, J. Ištvanić, M. Moro, J. Butković: ISKORIŠTENJE PRI IZRADI GRUBIH DRVNIH ELEMENATA... Šumarski list br. 9–10, CXXXIII (2009), 483-492 sortimente, Pilanska preradba niskokvalitetne neprave srži, Magistarski rad, Mašinski fakultet bu kovine i ostalih liščara prvenstveno sa aspekta Univerziteta u Sarajevu. industrije namještaja, Šipad – Istraživačko raz Zubčević, R.,1973: Utjecajni faktori pri izradi grubih vojni centar, Živinice. obradaka iz niskokvalitetne bukove pilanske obloPalovič, J.,1973:The influence of the quality of Be -vine, Disertacija, Mašinski fakultet u Sarajevu. ech roundwood on the yield of sawn timber and Zubčević, R.,1983: Utjecaj kvalitete i dimenzija bufurniture stock, Holzindustrie., 26(7): 211–215; kovih trupaca na iskorištenje, Drvna industrija, NLL; 8 ref. 34(5–6): 131–136. Prka, M., Ž. Zečić,A. P. B. Krpan, D. Vusić, HRN D. B4. 028 – 1979.Trupci za piljenje, Listopadno 2009: Characteristics and share of European drvo, Hrvatski zavod za norme, Zagreb. beech false heartwood in felling sites of Central HRN D. C1. 022– 1982.Piljena bukova građa,Hrvat- Croatia, Croatian Journal of Frestry Engine- ski zavod za norme, Zagreb. ering, 30 (1): 37–49. Škaljić, N.,2002: Simulirano piljenje kvalitetnih bukovih trupaca u zavisnosti od položaja i veličine SUMMARY: By agreement, and in practice sometimes without that agreement, to sawmills sometimes are delivered logs which do not fit regulations for standard saw logs. Often those logs are below standard quality or dimensions. Namely, sawmills compensate the lack of standard saw logs, in aspiration to fully use own capacities, by processing round wood with smaller dimensions; so called thin round wood. In this form of sawmill raw material, diameter dimensions and more often quality are below regulations for sawmill raw materials (sawmill logs). Diameter of thin round wood can range from 15 to 24 cm, and length can range from 2 m and above. Apart from thin round wood, high quality stacked wood in form of split or round wood (pulpwood, firewood, chemical conversion wood and others) can be used as input raw material. Nevertheless, that sort of raw material is infrequently used in large industrial sawmills, due to the problematic profitability of sawmill processing and unique sawmill technological basis. Considering the yield at sawing of these logs it is apparent that it is different from yield at processing of standard sawmill raw material. Research aim of this paper was to determine volume yield, lumber value yield and log value yield of common beech (Fagus sylvatica L.) logs with smaller diameter and quality during their processing dimension stock and flooring components. The study is based on common beech trees harvested in Bosnia and Hercegovina. The object of research were beech logs divided into three groups with mid diameter ranging from 18 to 20, 21 to 23 and 24 to 26 cm (Table 1 to 3). Primary sawing of logs was performed by using live sawing technique on long band saw. All obtained sawn boards were sawn up into dimension stock and flooring components by cross – rip sawing method. The best log volume yield in the form of dimension stock and flooring components showed logs with mid diameter ranging from 24 to 26 cm, followed by logs with diameter from 21 to 23 cm, and logs with diameter from 18 to 20 cm, with mutual insignificant difference (Figure 1 and Table 8). Results show that the best quality dimension stock and flooring components were sawn from logs with mid diameter ranging from 21 to 23 cm, followed by logs with diameter from 24 to 26 cm, and logs with diameter from 18 to 20 cm (Figure 2 and Table 9) . The best log value yield results showed logs with mid diameter ranging from 24 to 26 cm, followed by logs with diameter from 21 to 23 cm, and logs with diameter from 18 to 20 cm (Figure 3 and Table 10). The results confirmed some previous research. They indicate the possibility of successful processing of this kind of raw material regarding the research of technological criteria. In doing so, raw material selection and its qualitative classification is very important. Quality criteria and dimensions of dimension stock and flooring components which will be produced from that raw material are also important. In this paper the usage of three very confined diameter groups was compared. It was determined that there is slight but insignificant mutual difference. With further research it should be considered if there is any sense comparing such confined diameter groups, namely experiments should be set so that wider diameter groups are compared. Considering the market status of beech sawmill products, more attention should be given to economic indicators and success criteria of sawmill processing of this form of sawmill raw material. Key words:Common beech (Fagus sylvaticaL.), low quality and small-sized diameter logs, sawmilling production, dimension stock, log volume yield, lumber value yield, log value yield. |