Morpho-anatomical Evaluation of Stem Wood and Bark Fibers of Solanum dulcamara and Genista tinctoria for Paper Applications

As paper remains an essential material in communication, packaging, and various industrial applications, rising demand and the depletion of wood-based raw materials have prompted growing interest in renewable non-wood fiber sources. Alternative fiber sources for paper production have emerged as important non-traditional supply sources due to rising demand for fiber raw materials, a global tree crisis, and growing awareness of sustainability. This study evaluates the morpho-anatomical properties of fibers obtained from the stem wood and stem bark of Solanum dulcamara and Genista tinctoria in order to investigate environmentally sustainable and renewable non-wood fiber sources. The lengths, widths, lumen widths and wall thicknesses of the fibers, as well as slenderness ratio (related to paper mechanical properties), flexibility ratio (related to fiber bonding potential) and Runkel ratio (associated with pulp quality) were determined. It was determined that the bark samples of both species had longer, thicker-walled and narrower lumen fibers than the wood samples. Overall, the morphological properties of G. tinctoria fibers make them suitable for packaging papers that require moderate strength and flexibility. In contrast, the wood fibers of S. dulcamara appear suitable for low-strength paper applications due to their short and narrow structure, while its bark fibers show potential for high-strength paper applications, provided that fiber clustering is managed—highlighting both species as promising non-wood fiber sources for diverse paper products.