Wood Science and Technology

, Volume 47, Issue 3, pp 499–513 | Cite as

Distribution of preservatives in thermally modified Scots pine and Norway spruce sapwood

  • Sheikh Ali AhmedEmail author
  • Lars Hansson
  • Tom Morén


Studying the impregnation and distribution of oil-based preservative in dried wood is complicated as wood is a nonhomogeneous, hygroscopic and porous material, and especially of anisotropic nature. However, this study is important since it has influence on the durability of wood. To enhance the durability of thermally modified wood, a new method for preservative impregnation is introduced, avoiding the need for external pressure or vacuum. This article presents a study on preservative distribution in thermally treated Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) sapwood using computed tomography scanning, light microscopy, and scanning electron microscopy. Secondary treatment of thermally modified wood was performed on a laboratory scale by impregnation with two types of preservatives, viz. Elit Träskydd (Beckers) and pine tar (tar), to evaluate their distribution in the wood cells. Preservative solutions were impregnated in the wood using a simple and effective method. Samples were preheated to 170 °C in a drying oven and immediately submerged in preservative solutions for simultaneous impregnation and cooling. Tar penetration was found higher than Beckers, and their distribution decreased with increasing sample length. Owing to some anatomical properties, uptake of preservatives was low in spruce. Besides, dry-induced interstitial spaces, which are proven important flow paths for seasoned wood, were not observed in this species.


Thermal Modification Turpentine Resin Canal Preservative Solution Longitudinal Tracheid 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Financial support from the European Union and the European Regional Development Fund, the County Administration of Västerbotten, the municipality of Skellefteå, and TräCentrum Norr is gratefully acknowledged.


  1. Ahmed SA, Morén T (2012) Moisture properties of heat-treated Scots pine and Norway spruce sapwood impregnated with wood preservatives. Wood Fiber Sci 44:85–93Google Scholar
  2. Ahmed SA, Sehlstedt-Persson M, Karlsson O, Morén T (2012) Uneven distribution of preservative in kiln-dried sapwood lumber of Scots pine: impact of wood structure and resin allocation. Holzforschung 66:251–258CrossRefGoogle Scholar
  3. Alén R, Kotilainen R, Zaman A (2002) Thermochemical behavior of Norway spruce (Picea abies) at 180–225 °C. Wood Sci Technol 36:163–171CrossRefGoogle Scholar
  4. Andersson S, Serimaa R, Väänänen T, Paakkari T, Jämsä S, Viitaniemi P (2005) X-ray scattering studies of thermally modified Scots pine (Pinus sylvestris L.). Holzforschung 59:422–427CrossRefGoogle Scholar
  5. Awoyemi L, Jones IP (2011) Anatomical explanations for the changes in properties of western red cedar (Thuja plicata) wood during heat treatment. Wood Sci Technol 45:261–267CrossRefGoogle Scholar
  6. Bailey PJ, Preston RD (1970) Some aspects of softwood permeability. II. Flow of polar and non-polar liquids through sapwood and heartwood of Douglas fir. Holzforschung 24:37–45CrossRefGoogle Scholar
  7. Bamber RK (1972) The formation and permeability of interstitial spaces in the sapwood of some Pinus species. J Inst Wood Sci 6:36–38Google Scholar
  8. Bekhta P, Niemz P (2003) Effect of high temperature on the change in color, dimensional stability and mechanical properties of spruce wood. Holzforschung 57:539–546CrossRefGoogle Scholar
  9. Booker RE (1990) Changes in transverse wood permeability during the drying of Dacrydium cupressinum and Pinus radiata. NZ J For Sci 20:231–244Google Scholar
  10. Booker RE, Evans JM (1994) The effect of drying schedule on the radial permeability of Pinus radiata D. Don. Holz Roh- Werkst 52:150–156CrossRefGoogle Scholar
  11. Chayen J, Bitensky L (1991) Practical histochemistry, 2nd edn. Wiley, Chichester, pp 112–113Google Scholar
  12. Dagbro O, Torniainen P, Karlsson O, Morén T (2010) Colour responses from wood, thermally modified in superheated steam and pressurized steam atmospheres. Wood Mater Sci Eng 5:211–219Google Scholar
  13. De Groot RC (1994) Comparison of laboratory and field methods to evaluate durability of preservative-treated shakes. Wood Fiber Sci 26:306–314Google Scholar
  14. Doi S, Kurimoto Y, Ohmura W, Ohara S, Aoyama M, Yoshimura T (1999) Effects of heat treatment of wood on the feeding behavior of two subterranean termites. Holzforschung 53:225–229CrossRefGoogle Scholar
  15. Franklin GL (1945) Preparation of thin sections of synthetic resins and wood-resin composites, and a new macerating method for wood. Nature 155:51CrossRefGoogle Scholar
  16. Jämsä S, Viitaniemi P (2001) Heat treatment of wood- Better durability without chemicals. In: Rapp AO (ed) Review on heat treatments of wood. Proceedings of special seminar, Antibes, France, pp 21–26, 9 FebGoogle Scholar
  17. Jinxing L (1989) Distribution, size and effective aperture area of the inter-tracheid pits in the radial wall of Pinus radiata tracheids. IAWA Bull ns 10:53–58Google Scholar
  18. Kamdem DP, Pizzi A, Jermannaud A (2002) Durability of heat-treated wood. Holz Roh- Werkst 60:1–6CrossRefGoogle Scholar
  19. Karlsson O, Sidorova E, Morén T (2011) Influence of heat transferring media on durability of thermally modified wood. BioResources 6:356–372Google Scholar
  20. Kollmann FFP, Côté WA (1984) Principles of wood science and technology. Volume I: solid wood. Springer, Berlin, p 592Google Scholar
  21. Liese W, Bauch J (1967) On the closure of bordered pits in conifers. Wood Sci Technol 1:1–13CrossRefGoogle Scholar
  22. Lindgren O, Davis J, Wells P, Shadbolt P (1992) Non-destructive wood density distribution measurements using computed tomography. Holz Roh- Werkst 50:295–299Google Scholar
  23. Metsä-Kortelainen S, Antikainen T, Viitaniemi P (2006) The water absorption of sapwood and heartwood of Scots pine and Norway spruce heat-treated at 170 °C, 190 °C, 210 °C and 230 °C. Holz Roh- Werkst 64:192–197CrossRefGoogle Scholar
  24. Olsson T, Megnis M, Varna J, Lindberg H (2001) Study of the transverse liquid flow paths in pine and spruce using scanning electron microscopy. J Wood Sci 47:282–288CrossRefGoogle Scholar
  25. Petty JA, Preston RD (1969) The removal of air from wood. Holzforschung 23:9–15CrossRefGoogle Scholar
  26. Rak J (1976) Leaching of toxic elements from spruce treated with ammoniacal solutions of copper-zinc-arsenic preservatives. Wood Sci Technol 10:47–56CrossRefGoogle Scholar
  27. Rhatigan RG, Freitag C, El-Kasmi S, Morell JJ (2004) Preservative treatment of Scots pine and Norway spruce. For Prod J 54:91–94Google Scholar
  28. Sailer M, Rapp AO, Leithoff H, Peek R-D (2000) Upgrading of wood by application of an oil-heat treatment. Holz Roh- Werkst 58:15–22 (in German with English abstract)CrossRefGoogle Scholar
  29. Sandberg K, Salin J-G (2010) Liquid water absorption in dried Norway spruce timber measured with CT scanning and viewed as a percolation process. Wood Sci Technol 46:207–219CrossRefGoogle Scholar
  30. Scheepers G, Morén T, Rypstra T (2007) Liquid water flow in Pinus radiata during drying. Holz Roh- Werkst 65:275–283CrossRefGoogle Scholar
  31. Siau JF (1972) The effects of specimen length and impregnation time upon the retention of oils in wood. Wood Sci 4:163–170Google Scholar
  32. Terziev N, Daniel G (2002) Industrial kiln drying and its effect on microstructure, impregnation and properties of Scots pine timber impregnated for above ground use. Part 2. Effect of drying on microstructure and some mechanical properties of Scots pine wood. Holzforschung 56:434–439Google Scholar
  33. Thomas RJ, Kringstad KP (1971) The role of hydrogen bonding in pit aspiration. Holzforschung 25:143–149CrossRefGoogle Scholar
  34. Tjeerdsma BF, Boonstra M, Pizzi A, Tekely P, Militz H (1998) Characterisation of thermally modified wood: molecular reasons for wood performance improvement. Holz Roh- Werkst 56:149–153CrossRefGoogle Scholar
  35. Walters CS, Côté WA (1960) The distribution of pentachlorophenol in the micro-structure of basswood. Holzforschung 14:183–189CrossRefGoogle Scholar
  36. Weigenand O, Militz H, Tingaut P, Sèbe G, de Jeso B, Mai C (2007) Penetration of amino-silicone micro- and macro-emulsions into Scots pine sapwood and the effect on water-related properties. Holzforschung 61:51–59CrossRefGoogle Scholar
  37. Westin M, Rapp A, Nilsson T (2006) Field test of resistance of modified wood to marine borers. Wood Mater Sci Eng 1:34–38CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Department of Engineering Sciences and Mathematics, Division of Wood Science and Engineering, Wood PhysicsLuleå University of TechnologySkellefteåSweden

Personalised recommendations