Comparative study of wood properties for Quercus cerris l. (Turkey oak) from different sites in Hungary

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Absztrakt (kivonat)

Floral ecophysiologists and foresters in Europe and Hungary have classified Quercus cerris L. (Turkey oak), a temperate hardwood species, as a drought-tolerant tree species. In Hungary, the species is a lesser-used timber material. This research investigated the effects of soil quality and stand composition on wood tissues of Turkey oak in Hungary. Four trees were randomly harvested from each of the five selected Counties in Hungary. Further in Vas County only were plots under the influence of soil quality and stand composition, where four trees were randomly harvested from each. Logs processing, wood samples preparation and testing were performed at the Natural Resources Research Centre of the University Sopron (Soproni Egyetem, Hungary). Wood materials from Vas had the highest mean heartwood proportions of 75% followed by materials from Baranya with 71%. The combination of soil quality and stand composition had a slight statistically significant effect on the heartwood-sapwood proportion. The mean annual tree-ring width (TRW) for the wood materials ranged from 1.32 to 3.68 (mm). The Juvenile portion of materials from Baranya recorded the widest mean TRW (3.68 mm). Overall, the TRWs for Turkey oak trees planted in mixed stands were larger than trees from pure species stands. Similarly, the early- and latewood widths recorded were larger for Turkey oak trees from mixed species stands. There was a weak to moderate positive correlation between precipitation and TRW. The correlation between maximum temperature and TRW was negative. The mean values of fibre length (FL) ranged from 1065.14 to 1529.27 (µm). The highest mean FL of 1529.27 was recorded for sapwood portion of materials from Komárom-Esztergom. Wood materials from the Gyor-Moson-Sopron (GMS) recorded the lowest FL. The mean values of fibre double wall thickness (FDWT) ranged from 12.94 to 15.13 (µm). The minimum mean value was from GMS heartwood materials whereas the maximum value was from the sapwood of trees from Vas. Considering soil quality plots within the Vas County, the mean values for FL of wood from good and poor soil were 1096.69291 m and 1179.59201 m, respectively. FDWT were 13.75.24 m and 16.674.98 m, respectively. Regarding stand composition plots within Vas Country, FL for wood from mixed- and pure-stands were 1273.6192 m and 975.89223 m, whereas its corresponding FDWT 17.295 m and 12.924 m, respectively. The results indicate that Turkey oak wood from mixed stands, irrespective of soil quality, produced wood with longer fibres and thicker walls. On good quality soil, the average vessel diameter was 111.4438 m, whereas on poor quality soil the average was 236.87140 m. Vessel length was similar in both earlywood and latewood portions, their diameters were expectedly larger in the earlywood portion. The proportion of vessels was greater in wood from pure stands. The mean values for vessel proportion ranged from 40 – 44%, and that of fibre 39 – 43%. Counterparts from mixed-species stands expressed mean vessel proportion ranging from 32 – 34%, and fibre from 44 – 47%. Basic wood density values ranged from 0.65 to 0.87 g/cm3. The wood materials from mixed-species exhibited higher basic density. The bending modulus of elasticity (MoE) ranged from 8929.74 to 15954.08 (MPa). Higher mean values were recorded for wood materials from mixed-species stands. The bending strength ranged from 104.04 to 167.89 (MPa). The compression strength parallel to the grain ranged from 49.55 to 70.08 MPa. Stand composition and soil quality had significant influence on basic density, MoE and MoR. Janka hardness_longitudinal ranged between 77.15 to 106.71 N/mm2. The same variable tested on radial surface ranged between 63.22 to 88.26 N/mm2 whereas on tangential surface ranged between 64.43 to 93.10 N/mm2. Turkey oak wood materials from mixed-species planting exhibited better mechanical properties apart from compression strength. Hungarian Turkey oak is recommended for valuable applications such as floorings, furniture and cabinets and lasting structural constructions.

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