Effect of fungal degradation on physicochemical properties of exploited stumps of oriental beech over a 25-year felling period and the obtained Kraft pulp properties

Abstract

Oriental beech (Fagus orientalis Lipsky) is the most important and valuable industrial wood species in the Hyrcanian forests in the north of Iran mainly used for furniture, veneer, composite, and papermaking industries. The present research was conducted in 2014 aimed at investigating the physicochemical changes of the felled oriental beech stumps over a 2–25 year period, and likewise the feasibility of using the given stumps as an alternative resource for wood pulp production. To do so, the effects of in-situ decay of beech stumps on their physical (wet and dry weights of wood, wet apparent density, and dry apparent density) and chemical (cellulose, hemicellulose, lignin, extractives, and total mass of carbohydrates) properties over a 2–25 year felling period were studied. The effects of the given decay period were also studied on the obtained Kraft pulp yield and Kappa number. The results indicate that the wet and dry apparent densities as well as the wet and dry weights of the wood samples decreased over the study period. Also, the results show that approximately 30% of the total mass of carbohydrates was degraded by the ambient fungi over the initial two years of felling, whereas the same property was reduced by 60% after 25 years. The Kraft pulp yields obtained from 2- and 25-year decayed stumps were 22.5% and 8.4%, respectively. The fungal degradation of wood chemical compounds could considerably reduce pulp yield and Kappa number by 62.8% and 74.2%, respectively. The results of a stepwise multivariate regression model evidence that cellulose not only affects the Kappa number but also owns a greater share (vs. lignin) in modelling the Kappa number. This reveals that the intensity of cellulose degradation, due to fungal exposure, is significantly higher than that of the other components of beech stumps in the studied forest area.

Effects of multiple extrusions on structure–property relationships of hybrid wood flour/poly (vinyl chloride) composites

“…20,21,24,[27][28][29] The existing publications evidence that water absorption of repeatedly recycled wood plastic composites (WPCs) depends on many variables such as interface quality, chemical composition, fiber length and distribution, density, and wood extractives. [30][31][32][33] The results confirm that globally recycling process reduces water absorption rates, thus boosting dimensional stability in WPCs. This is mainly due to better fiber dispersion, higher density, fewer and smaller voids, better fiber/polymer interfacial adhesion, and enhanced hydrophobicity in reprocessed polypropylene and polyethylene WPCs.…”

Suppression of Ganoderma boninense Using Benzoic Acid: Impact on Cellular Ultrastructure and Anatomical Changes in Oil Palm Wood

“…A similar study was also reported by Rees, where the primary infection starts when oil palm roots in contact with fungal mycelia, and penetration occurred through the unwounded root. Invasion of root cortex and parenchyma resulted in the development of holes in all cell wall layers and rapid progression of colonization of the lower stem [27] increasing wood porosity and easier penetration [23]. Degradation of cell wall resulted in the formation of cavities within cell wall [27], separation of the parenchymatous cells and fibers in the early stage.…”

“…Ganoderma boninense is a white-rot fungus due to its ability to enzymatically degrade lignin, a component of oil palm wood. This enzymatic degradation causes a decrease in wood strength during the initial stages of decay [13,22,23]. White-rot fungi play a crucial role in the short-term conversion and degradation of wood polysaccharides [13,24].…”

“…Simultaneous degradation breaks down all structural components, lignin, cellulose and hemicellulose, whereas selective degradation breaks down lignin and hemicelluloses, leaving cellulose-rich wood [13,[25][26][27]. The degradation of these components results in the rapid reduction of wood weight [13,23].…”

Advanced natural fibre-based fully biodegradable and renewable composites and nanocomposites: a comprehensive review

“…Other synthetic biodegradable polymers such as PVA and polyamide have also been reinforced with natural fibres and nanofibres. The results indicated that the addition of such reinforcements could improve the mechanical strength and moduli (due to the stiffening effect of natural fibres) and thermal stability of the resulting biocomposites, which the latter can be attributed to the reduced polymer chain mobility brought about by nanofibre inclusion (Kakroodi et al 2014;Naghdi et al 2015;Oliver-Ortega et al 2016;Yousefi et al 2017;Rahmati et al 2019).…”