Structural Characterization of the Variable Uptake and Distribution of Impregnation Fluids in Fast-Growing Poplar Hybrids
Biomaterials
Forestry
Final Report Abstract
The objective of this research project was to conduct a wood anatomical analysis of the treatability of plantation-grown poplar (Populus × canadensis), with particular emphasis on the structural influencing factors of tylosis formation and tension wood development. Despite the generally good treatability of poplar sapwood, previous studies and practical experience have shown inhomogeneous penetration of impregnation solutions, particularly in the transition zone between sapwood and heartwood (Abb. 1). This phenomenon was investigated through two coordinated sub-studies (TV1 and TV2) involving different genotypes (Dorskamp, Gelrica, Robusta). The first research focus involved macro- and microscopic characterization of the wood structure (TV1). Key vessel properties—such as diameter, density, and degree of tylosis formation—along with pit characteristics, were examined using scanning electron microscopy (SEM), digital light microscopy (DLM), and micro-computed tomography (micro-CT). The results revealed substantial variation in tylosis formation across different stem cross-sectional zones, with the highest occurrence in the transition zone between sapwood and heartwood. In TV2, it was demonstrated that immediate technical drying after harvesting markedly reduced subsequent tylosis formation. Tension wood was identified over large areas both macroscopically and microscopically. Pit geometry analysis revealed that, compared to normal wood, tension wood fibres exhibited significantly smaller and fewer pits, suggesting locally reduced permeability. The second research focus addressed the treatability of poplar boards using a fluorescent rhodamine B solution. Clear differences in penetration behavior were observed between different stem zones. While sapwood could generally be impregnated homogeneously, the transition zone consistently exhibited large unstained areas. Quantitative analysis confirmed a significantly higher degree of tylosis in these non-impregnated areas and thus supported the results from TV1. The influence of tension wood on treatability was also observed only locally; however, completely non-impregnated areas could not be directly attributed to its presence. Overall, the findings demonstrate that tylosis formation is a critical factor affecting the treatability of plantation-grown poplar wood. This study contributes significantly to understanding.
Link to the final report
https://doi.org/10.34657/24088
Publications
-
Structural characterization of the variable impregnation of poplar wood. Konferenzbeitrag, Hardwood Conference 2022, Sopron, Ungarn, 12.-14. Oktober 2022. (open access)
Buschalsky, A.; Löning, S.; Militz, H. & Koddenberg, T.
-
Light microscopy studies on the variable uptake of impregnation fluids by poplar wood. Konferenzbeitrag, 19th Annual Meeting of the Northern European Network for Wood Science and Engineering, 11.-12. Oktober 2023, Ås, Norwegen. (open access)
Buschalsky, A.; Löning, S.; Grebe, A.; Koddenberg, T. & Militz, H.
-
Vergleich der Tüpfelcharakteristika von Normal- und Zugholz in Populus × canadensis. Konferenzbeitrag, 6. Holzanatomisches Kolloquium, 7.-8. November 2024, Dresden, Deutschland. (open access)
Buschalsky, A.; Militz, H. & Koddenberg, T.
-
Anatomical Barriers to Impregnation in Hybrid Poplar: A Comparative Study of Pit Characteristics in Normal and Tension Wood. MDPI AG.
Buschalsky, Andreas; Militz, Holger & Koddenberg, Tim
-
Macroscopic and microscopic investigations of the inhomogeneous distribution of impregnating agents in poplar wood ( Populus × canadensis Moench). Wood Material Science & Engineering, 1-13.
Buschalsky, Andreas; Löning, Sophie; Siegel, Karoline; Militz, Holger & Koddenberg, Tim
