Moisture conductivity of pine core wood in a tree trunk

The article considers the process of moisture transfer in wood during its hydrothermal treatment. Obtaining a high-quality dried material with minimal internal stresses is possible based on information about the amount of moisture current in the wood, expressed in terms of the moisture conductivity coefficient. The coefficient of moisture conductivity is greatly influenced by temperature, with an increase in which its value increases significantly. The intensity of the moisture current in the wood is influenced by the breed, the direction of the moisture current and the location of the wood in the tree trunk. The available information on the moisture conductivity of wood does not take into account the variability of the density of wood in the height of the tree trunk and is presented for the butt part of the trunk. The determination of the moisture conductivity coefficient was established in the radial and tangential directions for sound pine wood, taking into account the height of the trunk by the method of stationary moisture current. Experimentally, an increase in the value of the moisture conductivity coefficient of pine wood in the height of the trunk in its middle part by 1.6 times, and in the apex – by 2.05 times compared with the lump. The intensity of the moisture current in the radial direction is higher than in the tangential direction in wood from the butt part of the trunk by an average of 14.0%, from the middle part of the trunk – by 5.0%, and from the apex – by 16.0% regardless of the ambient temperature. The obtained patterns on the variability of the moisture conductivity coefficient of pine wood in trunk height show the expediency of carrying out preliminary sorting of wood before hydrothermal treatment, taking into account its location in the trunk of the tree. This will optimize the processes of drying and moistening of wood, justify rational modes of chamber and atmospheric drying.

1. Afshari Z., Malek S. Moisture Transport in Laminated Wood and Bamboo Composites Bonded with Thin Adhesive Layers – a Numerical Study. SSRN Electronic Journal, 2022. DOI: 10.2139/ssrn.4026076.

2. Alpatkina R.P. About moisture conductivity of the most important native tree species wood. Woodworking industry, 1967, no. 9, pp. 12–14. (In Russ.)

3. Artsikhovskaya N.V. Investigation of wood moisture conductivity. Proceedings of Institute of Forest, 1957, Т. 9: Questions of wood science, pp. 127–157. (In Russ.)

4. Chiniforush A.A., Valipour H., Akbarnezhad A.A. Water vapor diffusivity of engineered wood: Effect of temperature and moisture content. Construction and Building Materials, 2019, vol. 224, pp. 1040–1055.

5. Eitelberger J., Hofstetter K. Prediction of transport properties of wood be-low the fiber saturation point – A multiscale homogenization approach and its experimental validation. Part II: Steady state moisture diffusion coefficient. Composites Science and Technology, 2011, vol. 71, iss. 2, pp. 145–151.

6. Gorokhovskiy A.G., Shishkina E.E., Agafonov A.S. Convective drying of lumber based on controlled moisture exchange. IVUZ. Forest Journal, 2022, no. 1(385), pp. 166-172. DOI: 10.37482/0536-1036-2022-1-166-172. (In Russ.)

7. Gosteev Yu.A., Korobeynikov Yu.G., Fedorov A.V., Fomin V. M. Experimental determination of moisture conductivity of pine samples in the longitudinal direction during convective drying. Applied Mechanics and technical physics, 2003, vol. 44, no. 3, pp. 117–123. (In Russ.)

8. Hofstetter A.K., Eitelberger J. Сomprehensive model for transient moisture transport in wood below the fiber saturation point: Physical background, implementation and experimental validation. International Journal of Thermal Sciences, 2011, vol. 50, iss. 10, pp. 1861–1866.

9. Mikhailova Yu.S., Platonov A.D., Snegireva S.N., Kiseleva A.V., Mozgovoy N.V. Determination of the minimum height of the emission source from the chamber during drying of beech wood. Forestry Engineering Journal, 2019, T. 9, no. 4(36), pp. 117– 125. (In Russ.)

10. Platonov A.D., Voloshin S., Snegireva S.N., Kiseleva A.V., Mozgovoy N., Safonov A.O. Moisture conductivity of apple wood. Forestry Engineering Journal, 2018, vol. 8, no. 4(32), pp. 181–187. (In Russ.)

11. Platonov A.D., Snegireva S.N., Drapalyuk M. V., Novikov A.I., Kantieva E.V., Novikova T.P. Wood Quality along the Trunk Height of Birch and Aspen Growing in the Restoring Forests of Central Russia. Forests, 2022, vol. 13 (11), no. 1758. DOI: https://doi.org/10.3390/f13111758.

12. Platonov A.D., Snegireva S. N., Kantieva E. V., Bondarenko V.S., Kiseleva A.V. Moisture conductivity of pine wood damaged by fire during atmospheric drying. Promising resource-saving technologies for the development of the timber industry complex: materials of Int. sci.-pract. conf. of young scientists and students. Voronezh, 2023a, pp. 126–129. DOI: 10.58168/R-STDTIC2023_126-129. (In Russ.)

13. Platonov A.D., Snegireva S.N., Kantieva E.V., Kiseleva A.V. Heartwood moisture conductivity of standing pine damaged by running crown and strong surface wildfire. Forestry Engineering Journal, 2023b, vol. 13, no. 4 (52), p. 1, pp. 191–208. DOI: 10.34220/issn.2222-7962/2023.4/12. (In Russ.)

14. Rudak A.G., Snopkov B.V. Investigation of moisture conductivity of pine wood in various structural directions. Proceedings of BSTU. Series 2. Forestry and woodworking industry, 2010, no. 2, pp. 180–183. (In Russ.)

15. Sapozhnikov I.V., Skuratov N.V., Alekseeva I.I., Samoylenko D.A., Mamontov M.P., Matveeva K.A. Determination of the coefficient of moisture conductivity during lowtemperature drying of wood. Lesnoy vestnik. Forestry Bulletin, 2016, no. 4, pp. 34–39. (In Russ.)

16. Sergovskiy P.S. Calculation of wood dessication and humidification processes. M.: State Publishing House of Forest and Paper Industry, 1952. 75 p. (In Russ.)

17. Skuratov N.V., Usov D.V., Sergeev I.G. Vapor permeability and moisture conductivity of thermally modified ash wood. Annual nat. sci-tech. conf. for Professors, Lecturers, Postgraduate Students and Students of Mytitschi branch of MSTU named after N.E. Bauman based on results of R&D in 2021. Krasnoyarsk, 2022, pp. 113–115. (In Russ.)

18. Snegireva S.N., Platonov A.D., Kiseleva A.V., Kantieva E. V. Variability of the hardness of pine wood damaged by strong grassroots and rampant riding fire. Forestry Engineering Journal, 2022, vol. 11, no. 4., pp. 79–87. DOI: 10.34220/issn.2222-7962/2021.4/7.

19. Sotnikova M.A., Sokolova A.V. Development of methods and processes for dewatering wood and wood waste. Actual problems of the development of the forest complex: mater. of XVII int. sci.-tech. conf. Vologda: VoSU, 2019, pp. 178–181. (In Russ.)

20. Tyukavina O., Gudina A., Heating capability of postpyrogen-pine wood. Forestry Engineering Journal, 2020, vol. 10, no. 2, pp. 188–195. DOI: https://doi.org/10.34220/issn.2222-7962/2020.2/19.

21. Zaripov Sh.G., Kornienko V.A. On moisture exchange processes during convective drying in batch chambers of larch lumber. Coniferous boreal zones, 2021, vol. 39, no. 1, pp. 60–65. (In Russ.)

22. Zhan T., Sun F., Lyu C., He Q., Xu K., Zhang Ya., Cai L., Huang Zh., Lyu J. Moisture diffusion properties of graded hierarchical structure of bamboo: Longitudinal and radial variations. Construction and Building Materials, 2020, vol. 259, no. 119641. DOI: 10.1016/j.conbuildmat.2020.119641.