https://jfwp.ut.ac.ir/ Forest and Wood Products en daily 1 Sun, 23 Aug 2026 00:00:00 +0330 Sun, 23 Aug 2026 00:00:00 +0330 https://jfwp.ut.ac.ir/article_108780.html First, I would like to extend my condolences to the Iranian scientific community on the passing away of two distinguished professors of wood science: Prof. Kazem Doosthoseini and Prof. Saeed Amiri. May their memory be cherished. I would like to notify the authors that some recent changes have been made to the Instructions for Authors. Therefore, authors are kindly requested to carefully review the latest version of the guidelines before submitting their manuscripts. To facilitate the submission process and allow authors to focus more effectively on the scientific quality of their work, the journal has adopted a "free-format submission" policy. Consequently, strict adherence to formatting requirements, such as font type and size or the specified reference style is not required during the initial submission stage. Nevertheless, the submitted manuscript must be legible and complete, containing all necessary sections. Following peer review and acceptance, the manuscript must be prepared in accordance with the journal's guidelines. To facilitate the writing process, new manuscript and figure templates are now available in the Author Guidelines section. As previously mentioned, authors may use any standard citation style for the initial submission; however, upon acceptance, the references must be formatted precisely according to the APA Style, 7th Edition. Additionally, including the DOI as a full URL at the end of each reference is mandatory whenever a DOI is available. As this journal employs a double-blind peer-review process, authors are requested to remove section of Ethical Considerations (e.g., author contributions, funding, acknowledgments, etc.) from the manuscript to maintain anonymity. This section should be added only after the completion or approval of the review process. Authors must highlight all changes made to the manuscript by colored text to facilitate the final review. Following acceptance and the completion of the editing process, articles are published based on their readiness for publication, while adhering to the chronological order of acceptance and the completion of editorial revisions by the authors. Furthermore, the regulations of The Ministry of Science, Research and Technology (MSRT) regarding the annual limit on articles authored by editorial board members and a minimum percentage of articles per issue from authors outside the host institution are strictly observed. Accordingly, the current issue features six articles in the field of wood science and two articles in the field of forest science. In the field of cellulose-based industries, four articles have been published by researchers from University of Tehran, Islamic Azad University, Karaj Branch, Sari Agricultural Sciences and Natural Resources University, and Tarbiat Modares University. These studies address the production of cellulose from banana stem waste and recycled fibers, the development of effective and eco-friendly solutions for treating kraft pulp mill wastewater, and the enhancement of printing and writing paper properties. In another study, specialists from Gorgan University of Agricultural Sciences and Natural Resources modified the properties of urea-formaldehyde adhesive by encapsulation of magnetic nanoparticles for use in radio-frequency (RF) heated presses. Researchers from University of Tehran, in collaboration with specialists from the Agricultural Engineering Research Institute and The Iranian Research Organization for Science and Technology (IROST), successfully modified wood surfaces using plasma technology to enhance coating performance. In a study within the field of forest science, researchers from the West Azarbaijan Agricultural and Natural Resources Research and Education Center (AREEO) investigated the ecological status of Sumac (Rhus coriaria L.) habitats in this province, aiming to establish a principled plan for its conservation, restoration, expansion of cultivation, and sustainable utilization. In another study, researchers from University of Tabriz addressed phytoremediation and the selection of tree species effective in reducing and eliminating pollutants in the area of ​​the Sungun Copper Mine in East Azarbaijan Province. I sincerely thank all the authors for choosing this journal to publish their work. I also extend my sincere appreciation to the reviewers whose efforts throughout the review process contribute to enhancing the quality of the published papers. https://jfwp.ut.ac.ir/article_108781.html During the last summer, the scientific community in the fields of natural resources, and wood and paper science and technology suffered the loss of two distinguished scholars and respected authorities: Prof. Kazem Doosthoseini and Prof. Saeed Amiri. These two eminent professors played a pivotal role in educating and mentoring generations of students over many years. Today, many of their students are working as faculty members at universities and as professionals in industries across the country. Doosthoseini was born in Yazd in 1947. He began his university studies at the Faculty of Natural Resources, University of Tehran, in 1966; following the completion of his bachelor's degree, he undertook a one-year internship in Switzerland. He pursued his master's and doctoral studies at Université Laval, Canada, and was awarded his PhD on Self-bonding of Wood and Lignocellulosic Materials in 1980. He returned to Iran that same year, and joined the Department of Wood Science and Technology, Faculty of Natural Resources, University of Tehran. His teaching and research activities focused on wood-based composite products. One of his works, the book Wood Composites Materials: Manufacturing, Applications published by University of Tehran remains a reputable and widely cited scientific reference in both academia and industry. He attained the rank of full professor in 1998 and retired in March 2011 after years of academic service. A disciplined and diligent approach to work, and a strong sense of responsibility were among his most distinguished personal qualities. His five terms as head of the Department of Wood Science and Technology, two terms as vice dean for education and research affairs at the Faculty of Natural Resources, and membership in the supreme council of natural resources and faculty publications council, a member of the editorial board of Journal of Natural Resources and a five-year tenure as Editor-in-Chief of the journal, a member of The Academy of Sciences of the Islamic Republic of Iran, and head of the wood science division were only part of his academic and administrative contributions. Prof. Saeed Amiri was born in Sabzevar in 1938. After completing his Bachelor’s and Master’s studies in Forest Engineering and Forest Economics at the University of Göttingen in Germany, he began his academic career as a faculty member in the Department of Forestry and Forest Economics at the Faculty of Forestry in 1970, and subsequently joined the Department of Wood Science and Technology at the Faculty of Natural Resources, University of Tehran. In 1976, he pursued his doctoral studies in Forest and Wood Industry Economics at the University of Natural Resources and Life Sciences, Vienna (BOKU; Universität für Bodenkultur Wien), Austria, focusing on Timber Grading. He was one of the pioneers in developing education in Wood Industry Economics and Management in Iran. Humility, modesty, and an unpretentious nature were among his outstanding personal qualities. For many years, he served as the Chair of the National Committee for Wood Standards and Grading at the Iran National Standards Organization. The development of the Iranian National Standard for hardwood timber grading, Acceptable Defects of Logs and Gradation (Standard No. 1275) remains one of his enduring contributions. His other scholarly contributions include the publication of the book Situation und Entwicklung des Holxmarktes in Iran and his contribution to the co-authorship of the book Methods of Grading and Measuring Lumber and Log. He also served as the head of the Department of Wood Science and Technology at the University of Tehran for two terms, and as the head of Publication of the Journal of Natural Resources for one term. He retired in September 2004 after years of academic service.“Their memory and legacy will endure” https://jfwp.ut.ac.ir/article_107770.html Introduction: The present study investigates the ecological status of Sumac (Rhus coriaria L.) habitats in West Azerbaijan Province, Iran. The main objective is to elucidate the ecological conditions influencing the growth and development of this plant species in the region. Given the scarcity of regional data, this research aims to determine the appropriate habitat specifications for the cultivation and natural regeneration of Sumac in the province. Emphasizing the identification of ecological characteristics of these habitats for sustainable management and restoration constitutes a significant portion of this research’s goals.Method: This research was conducted in the central and southern parts of West Azerbaijan Province. Three habitats in Sardasht County (one natural and two semi-natural) and two natural habitats in Urmia County were selected as sample sites. Sampling was carried out using a systematic-random method. Soil samples (0–30 cm depth), fruit production (cluster weight), and quantitative species variables, including shrub height, diameter at breast height (DBH), canopy cover, collar diameter, number of clusters, number of sprouts, tree density, and number of stems per unit were evaluated. Given the extent of the habitats, three 200-meter longitudinal transects were established in each site. Along these transects, sample plots (3×3 m) were selected at 10-meter intervals for data collection. Two-way cluster analysis was performed between soil variables and biological variables, as well as among the habitats, to determine the similarities and dissimilarities between these factors. Principal Component Analysis (PCA) and two-way clustering were performed using the PAleontological STatistics (PAST) software, version 3.04.Results: Soil analysis results indicated variations in soil properties across the five studied habitats. Soil pH ranged from 7.0 to 7.9, salinity from 0.33 to 0.73 µS/cm, calcium carbonate from 0.93% to 1.87%, available phosphorus from 7.1 to 19 ppm, available potassium from 73.3 to 276 ppm, and organic carbon from 0.92% to 1.54%. A positive and significant correlation was observed between soil silt percentage and fruit weight per plant. The correlation coefficient between Sumac shrub height and soil potassium showed a significant negative relationship between these two parameters. Results from the Principal Component Analysis (PCA) indicate that the most significant factors influencing Sumac growth and development are soil potassium levels and soil texture (silt and sand percentages).Conclusion: The findings of this study demonstrate that the most important parameters influencing the differentiation of Sumac habitats in West Azerbaijan are fruit weight per plant, annual precipitation, soil potassium, and soil texture. Sumac’s dependency on water for reproductive growth and its requirement for sunlight are other key factors in determining habitat suitability. Furthermore, a complex relationship was observed between vegetative and reproductive growth, underscoring the importance of balancing these two growth aspects to maximize fruit production. These findings can provide a foundation for sustainable management, habitat restoration, and the selection of suitable sites for the cultivation and development of this valuable species. https://jfwp.ut.ac.ir/article_108038.html Introduction: The increasing production of bananas in tropical and subtropical regions generates substantial amounts of lignocellulosic residues, particularly banana pseudostems. These residues are often discarded or burned without effective utilization, despite containing significant amounts of cellulose, hemicelluloses, lignin, and fibrous constituents that can serve as renewable resources for the production of bio-based materials. Therefore, the objective of this study was to extract high-purity cellulose from banana pseudostem waste and to comprehensively evaluate its chemical composition, structural characteristics, crystallinity, thermal behavior, and degree of polymerization.Method: Banana pseudostem fibers were collected, washed, dried, and mechanically processed prior to treatment. The fibers were subjected to a mild alkaline treatment using a 4 wt. % sodium hydroxide solution at 75-80°C. Subsequently, a three-stage oxidative bleaching sequence was applied to further remove hemicelluloses, lignin, and extractive substances. Chemical composition and ash content were determined using standard analytical methods. Structural changes were investigated by Fourier-transform infrared spectroscopy (FTIR), crystallinity was evaluated using X-ray diffraction (XRD), thermal stability was assessed through thermogravimetric analysis (TGA), and the degree of polymerization was determined by viscometric measurements in cuprammonium hydroxide solution.Results: Chemical composition analysis revealed that the raw banana pseudostem fibers contained 35.5% cellulose, 28.9% hemicelluloses, 16.0% lignin, and 19.6% extractives. Ash content decreased from 14.94% in the raw fibers to 8.75% after alkaline pulping and further to 3.70% after bleaching, indicating the effective removal of mineral constituents and inorganic impurities. FTIR analysis confirmed the elimination of characteristic hemicellulose- and lignin-related absorption bands, while the bands associated with the β-(1→4)-glucan backbone of cellulose remained intact, demonstrating the preservation of the fundamental cellulose structure throughout the treatment process. XRD results showed a substantial increase in the relative crystalline fraction, with the crystallinity index rising from 57.87% in the raw fibers to 86.4% in the bleached fibers, which was attributed to the removal of amorphous components during pulping and bleaching. Furthermore, the degree of polymerization increased from 395 in the raw fibers to 1100 in the purified cellulose product. TGA analysis revealed enhanced thermal stability in the treated samples. In the DTG curves, the degradation peak associated with hemicelluloses within the temperature range of approximately 220–320 °C was markedly reduced and nearly eliminated, confirming the predominance of the cellulose phase in the final material.Conclusion: The findings demonstrated that the combination of mild alkaline treatment and oxidative bleaching is an effective approach for removing non-cellulosic constituents from banana pseudostem fibers and producing cellulose with high purity, crystallinity, thermal stability, and degree of polymerization. Accordingly, banana pseudostem waste can be considered a low-cost, renewable, and valuable feedstock for the production of cellulose fibers and bio-based materials within the framework of a circular bioeconomy. https://jfwp.ut.ac.ir/article_108142.html Introduction: Open‑pit mining operations generate substantial environmental disturbances, most notably the formation of massive waste rock piles and deep excavation pits. These waste deposits, composed largely of fragmented rock material, typically exhibit low moisture‑holding capacity, high bulk density, poor nutrient content, lower pH, and elevated concentrations of potentially toxic elements, including heavy metals. Such characteristics pose significant risks to both environmental and human health. Consequently, developing effective remediation strategies is essential. Among available approaches, phytoremediation leverages the capacity of plant species to extract, stabilize, or accumulate heavy metals from contaminated substrates. The present study aimed to evaluate the uptake of heavy metals by the leaves of Robinia pseudoacacia (black locust) and Fraxinus excelsior (ash) trees planted around the Sungun copper mine in Varzeqan, Iran.Method: Leaf samples were collected from mature black locust and ash trees (approximately 15–20 years old) established within the green belt surrounding the Sungun copper mine. Sampling trees were selected randomly from healthy, pest‑free individuals with intact crowns, using five trees per species and three replicates. From each tree, 20–30 leaves were harvested from the upper third of the canopy in a single sampling event. Samples were transported to the laboratory in paper bags and digested prior to analysis. Concentrations of copper (Cu), molybdenum (Mo), lead (Pb), and cadmium (Cd) were quantified using ICP‑MS. In addition, bioconcentration factor (BCF), comprehensive bioconcentration index (CBCI), and metal accumulation index (MAI) were calculated. Data normality was assessed using the Shapiro–Wilk test, followed by t‑tests to determine significant differences between species.Results: Statistical analyses revealed significant differences in the bioconcentration of Mo, Cu, Pb, and Cd between black locust and ash. According to t‑test results, black locust exhibited significantly higher leaf concentrations of all four metals compared with ash. Overall, the highest extraction levels across both species occurred in the order Cu > Mo > Pb > Cd. Concentrations of Cu, Pb, and Mo in all leaf samples exceeded standard permissible limits. Based on bioconcentration indices, black locust was identified as a specialized hyperaccumulator of Mo, whereas ash functioned as a Mo indicator species. For other metals, differences between species were less pronounced. MAI values further confirmed that black locust had the highest overall heavy‑metal accumulation capacity, and CBCI results similarly ranked black locust above ash. Species classification based on heavy‑metal uptake indicated that black locust acts as a Mo hyperaccumulator, while ash falls within the indicator category for Mo. Additionally, black locust showed strong affinity for Cu, Pb, and Cd, whereas ash demonstrated greater resistance to these metals.Conclusion: The combined evidence from bioconcentration indices demonstrates that black locust possesses superior capacity for heavy‑metal accumulation compared with ash and can be classified as a hyperaccumulator species in this context. Nevertheless, despite its lower index values, ash remains a viable candidate for phytoremediation, particularly in environments requiring species with moderate uptake but higher ecological resilience. This study provides an initial insight into the phytoremediation potential of these two species in mining‑impacted landscapes and highlights future research pathways for improving contaminated‑site management through biomonitoring and bioaccumulation assessment. https://jfwp.ut.ac.ir/article_108143.html Introduction: The pulp and paper industry is one of the most water-intensive industries and generates large volumes of highly polluted wastewater. Kraft pulp mill effluents contain considerable amounts of persistent organic compounds, lignin derivatives, dissolved solids, and suspended particles, resulting in high chemical oxygen demand (COD), turbidity, and a black color. Discharge of such wastewater without proper treatment poses serious environmental concerns. Various treatment methods, including biological processes, chemical coagulation, membrane technologies, and advanced oxidation processes, have been employed to reduce pollutant loads. However, their widespread application is limited by high operational costs, excessive chemical consumption, and large sludge production. In recent years, electrocoagulation has attracted considerable attention as an efficient and environmentally friendly wastewater treatment technology, because of its operational simplicity, low chemical requirement, and high capability for removing organic contaminants. Therefore, the objective of the present study was to investigate the effects of electrolysis time and initial pH on the efficiency of electrocoagulation for the treatment of kraft pulp mill wastewater.Method: Wastewater samples were collected from a hardwood kraft pulp mill located in northern Iran. The initial characteristics of the wastewater were COD of 860 mg/l, total dissolved solids (TDS) of 507 mg/l, and turbidity of 309 NTU. Electrocoagulation experiments were conducted in a batch reactor at room temperature under a constant voltage of 15 V. Iron and aluminum electrodes were used as the anode and cathode, respectively, without the addition of any supporting electrolyte. The initial pH of the wastewater was adjusted to four levels (3, 5, 7, and 10), while electrolysis time was varied at 10, 20, and 40 minutes. COD, TDS, and turbidity were measured before and after treatment according to APHA standard methods. All experiments were carried out in triplicate. Data were statistically analyzed using a factorial experiment based on a randomized complete block design, and mean comparisons were performed using Duncan's multiple range test at the 5% significance level.Results: The results indicated that increasing electrolysis time significantly improved the efficiency of the electrocoagulation process. The individual effects of electrolysis time and initial pH on COD, TDS, and turbidity were significant at the 99% confidence level, whereas their interaction effect was not significant. Increasing the electrolysis time from 10 to 40 minutes enhanced pollutant removal due to greater dissolution of the iron anode, increased formation of metal hydroxides, and improved adsorption and separation of contaminants. Initial pH also had a noticeable effect on treatment efficiency, with the highest removal efficiency observed under near-neutral conditions (pH= 5-7). Lower efficiencies obtained under strongly acidic and alkaline conditions were attributed to changes in iron hydroxide species and reduced floc stability. Under the optimum conditions (pH 7 and 40 minuntes of electrolysis time), COD, TDS, and turbidity decreased from their initial values of 860 mg/L, 507 mg/L, and 309 NTU to 298.5 mg/L, 264.5 mg/L, and 26.5 NTU, corresponding to reductions of 65%, 47%, and 91%, respectively.Conclusion: The results demonstrated that electrocoagulation using iron and aluminum electrodes is an effective, simple, and environmentally friendly method for the treatment of kraft pulp mill wastewater. Electrolysis time and initial pH were identified as the most influential operational parameters, and near-neutral conditions provided the highest pollutant removal efficiency. Overall, the process exhibited a high capability for reducing COD, TDS, and turbidity, and can be considered a promising option for pretreatment or supplementary treatment of pulp and paper mill effluents. https://jfwp.ut.ac.ir/article_108249.html Introduction: In the papermaking industry, mineral fillers are extensively used to reduce production costs and enhance the optical properties of paper. Precipitated calcium carbonate (PCC) is one of the most widely applied fillers due to its low cost, high availability, and excellent contribution to brightness and opacity. However, the major drawback associated with PCC application is its low retention within the fibrous network and the deterioration of paper strength properties. These limitations mainly result from weak interfacial interactions between PCC particles and anionic cellulose fibers, leading to filler loss during drainage and disruption of fiber–fiber bonding. To overcome these challenges, surface modification of PCC using biodegradable cationic polymers has been proposed as an effective strategy to improve filler–fiber compatibility and simultaneously enhance filler retention and paper performance. Therefore, the objective of this study was to investigate the effects of surface modification of PCC using cationic starch, chitosan, and their combination, as well as to evaluate the role of cationic polyacrylamide (CPAM) as a retention aid on the optical, structural, and mechanical properties of printing and writing paper.Method: In this study, PCC was surface-modified separately with cationic starch, chitosan, and a starch–chitosan blend. The modification process involved preparing PCC slurries, adding the cationic polymers under controlled pH and temperature conditions, followed by filtration, drying, and grinding of the modified fillers. Handsheets with a basis weight of 60 g/m² were produced using long-fiber pulp. In selected formulations, CPAM was added as a retention aid. The handsheets were evaluated according to TAPPI standard methods. Ash content was measured as an indicator of filler retention, while brightness, opacity, and apparent density were determined to assess optical and structural properties. Mechanical performance was evaluated by measuring tensile strength index, burst strength index, and tear strength index.Results: The results demonstrated that surface modification of PCC with cationic starch, compared to chitosan, yielded superior performance in simultaneously enhancing filler retention and mechanical properties. Although the addition of cationic polyacrylamide significantly increased filler retention in both systems (starch and chitosan), cationic starch showed a marked advantage due to its greater stability and the formation of more effective bonds with the fibers, particularly regarding strength properties (tensile and burst strengths). This improvement was attributed to strong electrostatic attractions and hydrogen bonding between starch-modified PCC particles and cellulose fibers, which enhanced filler entrapment within the paper structure. In addition, starch-modified PCC significantly improved optical properties, including brightness and opacity. Notably, this treatment also led to substantial improvements in mechanical properties, effectively compensating for the strength losses typically associated with filler addition.In contrast, PCC modified solely with chitosan exhibited limited performance. This behavior was mainly attributed to process-related limitations of chitosan, such as partial loss of cationic charge under near-neutral pH conditions and deactivation during acidic washing steps, which reduced its effective adsorption onto PCC surfaces. The combined use of starch and chitosan did not provide a significant advantage over cationic starch alone, indicating that the performance of this system was largely governed by starch. Although CPAM generally enhanced filler retention, its simultaneous use with multiple cationic polymers occasionally caused excessive flocculation, leading to irregular filler aggregation and reduced mechanical strength. Conclusion: Overall, the findings of this study indicate that surface modification of PCC with cationic starch is a highly efficient, biodegradable, and reliable strategy for improving filler retention as well as the optical and mechanical properties of printing and writing paper. In contrast, the effective application of chitosan requires careful control of processing conditions to maintain its cationic functionality. These results provide valuable insights for the development of sustainable and optimized filler modification strategies in modern papermaking. https://jfwp.ut.ac.ir/article_108351.html Introduction: Wood surface coating is usually done to improve the appearance, improve surface performance and thus increase the lifespan of wooden structures. However, the main problem is that most coatings are separated from the wood surface after exposure to humidity and site conditions, reducing the physical and mechanical properties of the structure. The main objective of this research is to modify the wood surface using modern plasma technology; in such a way that the durability of protective coatings for indoor and outdoor applications is increased and their premature separation is prevented.Method: In this research, two types of transparent and colored (white) polyurethane protective coatings were used to cover the wood surface. Beech (Fagus sylvatica) wood surfaces were treated with dielectric barrier discharge (DBD) plasma pretreatment in a nitrogen gas environment for different times of 30, 60, 120 and 240 seconds before coating. After the treatments, various physicochemical and mechanical tests such as attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were performed to investigate the chemical changes of the surface, colorimetry to evaluate the visual and color changes of the surface, roughness to measure the changes in surface morphology, and abrasion resistance testing to investigate the mechanical durability of the coatings on coated and uncoated surfaces. Results: The results of the study showed that plasma pretreatment increased the roughness of the wood surface, although it did not have a significant effect on the color factors of the surface. The main changes in the color components of the wood surface were affected by the type of coating, and colored polyurethane showed the greatest effect in this regard. Also, the roughness on colored coatings was somewhat higher than on clear coatings. In terms of mechanical properties, plasma pretreatment reduced the wear coefficient in all polyurethane coatings on beech wood, which indicates improved wear resistance and increased durability of the coating. The ATR-FTIR spectroscopy results also confirmed the chemical changes of the pretreated wood surface and the successful presence of the polyurethane coating.Conclusion: Overall, plasma pretreatment at optimal time and conditions increased the durability of both types of polyurethane coatings (clear and colored) by modifying the wood surface morphology without negatively affecting the aesthetic properties. Since the pigments present in colored polyurethane and the aesthetic importance of clear coatings are combined with the synergistic effect of plasma technology, the potential for the application of these coatings in interior and exterior applications such as flooring, outdoor furniture, and decorative and ornamental industries is significantly increased. https://jfwp.ut.ac.ir/article_108627.html Introduction: Development new adhesives and modification of common adhesives are two main fields for wood-based composite studies. Usually, in order to evaluate adhesive performance, some products are made according to certain treatments that increase the research costs and time. The alternative method is the evaluation of strength and rheology properties on a smaller scale but at higher speed and precision in which the adhesive is applied in tiny amounts on smaller samples and hot pressing is done with high accuracy. This technique is performed by an Automated Bonding Evaluation System (ABES) according to a standard method. Method: In this study it was required to modify UF resin by adding nano-magnetic particles to use in plywood production in high frequency heating process. To prevent nano particle aggregation, encapsulation technique for the particles was applied. For this purpose, three types of material, including starch, PEG and Acacia gum were used under various mixing conditions. Then, the performance of the mixing method and material type was controlled qualitatively via visual inspection. After that, 20% of different suspensions were added to UF and the gel time of the modified adhesives were obtained with the Adhesive Bonding and Rheology Evaluating System and compared to each other. After determination of appropriate composition, another investigation was done to obtain shear strength development isothermal graphs as a function of press time. For this purpose lap-joint samples of Beech strands with 0.6 mm thickness and 20Î5 mm2 area, were made under compositions of press temperature and time as variables in three levels of 80, 100 and 120 °C and five levels of 40, 60, 80, 100 and 120 s respectively. Then, the shear strength of them was tested with tension loading system. By investigating the obtained graphs, the trend of shear strength development due to press time and press temperature were determined in different adhesive compositions and the optimum one was selected. In the final stage, to investigate the effect of the encapsulated nano particles load in the adhesive matrix, different levels (0%, 4%, 8%, 12%, 16% ,20% and 24%) of selected compound were added to UF resin. Lap-joints were made similar to those in previous stage but with the optimum temperature and time conditions (100 °C press temperature and 90 s press time), and the shear strength was measured on the specimens. Results: The results showed that the type of encapsulating material has certain effect on the uniform distribution of particles as well as gelation time, and among the three applied encapsulation materials, starch had the best performance. With the presence of encapsulated nano-magnetic particles in UF, the bondline shear strength improved. The amount of this increase compare to pure UF was obtained 2.2%, 5.96%, 8.2%, 7.3%, 9.4% and 8.92% respectively for treatments with 4%, 8%, 12%, 16%, 20% and 24% encapsulated nano-magnetic particles. The isothermal graphs of shear strength development of the modified adhesive showed that the relation between press time and strength was linear until 80 s and then became nonlinear.Conclusion: This study found that the encapsulation of nano-magnetic particles with starch could lead to uniform suspension without accumulation and their presence in UF matrix up to 24% based on adhesive solid mass, didn't have a negative influence on the shear strength of the bondline. Application of this suspension not only caused no disruption to UF curing but also reduced the time of this process compared to pure resin. https://jfwp.ut.ac.ir/article_108641.html Introduction: With the increasing attention to sustainable development and renewable resources, cellulose, as the most abundant natural polymer, is considered an ideal option for the production of biocompatible products. However, its dissolution in common solvents is challenging due to the extensive network of hydrogen bonds, and conventional methods are not sufficiently efficient due to high costs or toxicity. In this regard, the aqueous alkaline solution of sodium hydroxide is known as an inexpensive and biocompatible solvent, and previous studies have shown that the addition of urea improves the performance of this alkaline system. It also appears that thiourea may be effective in combination with alkali in the dissolution of cellulosic carbohydrates. On the other hand, recycled fibers have attracted special attention as a valuable source of cellulose. Accordingly, the aim of the present study was to optimize the alkaline dissolution of recycled printing and writing paper fibers in aqueous urea/sodium hydroxide and thiourea/sodium hydroxide systems, and to investigate the effects of process variables on dissolution efficiency, degree of polymerization, functional groups, crystalline structure, and cellulose film morphology.Method: Unprinted, edge-trimmed printing and writing papers were converted into pulp with 1.5% consistency using a Valley Beater refiner. The fibers were first dissolved in a water/urea/sodium hydroxide solvent with weight ratios of 91:2:7 and 89:4:7, at process temperatures of –10, 0, and +10 °C. In the second phase, the fibers were dissolved in an aqueous thiourea/sodium hydroxide system with the aforementioned weight ratios at the temperature selected from the previous stage (–10 °C). Additionally, the water/urea/thiourea/sodium hydroxide mixture with a weight ratio of 89:2:2:7 was investigated at –10 °C. In all treatments, the solvent-to-fiber ratio was 100:1. After centrifugation, the dissolution yield was determined gravimetrically. The degree of polymerization was measured by viscometry, functional groups by FTIR, crystalline structure by XRD, and surface morphology by FESEM. Cellulose films were prepared from a 1 wt% solution by neutralization with 5% H₂SO₄, washing with water and acetone, and drying at 70 °C.Results: Increasing urea concentration from 2% to 4% increased the dissolution yield from 27.37% to 37.22%, and –10 °C was identified as the optimal temperature. The 4% thiourea system exhibited the highest dissolution (55.05%) and the highest degree of polymerization (624.3), while the combined urea/thiourea system achieved 49.45% dissolution with DP ≈ 556 and the lowest crystallinity (8.65%). The urea and thiourea systems showed crystallinity values of 47.95% and 15.32%, respectively. Increasing the temperature to +10 °C in the urea-containing system reduced the dissolution to 10.2%, while DP decreased from 490 to 376. FTIR spectra confirmed the preservation of the chemical structure of cellulose and physical dissolution (no new bond formation), and FESEM images confirmed the formation of a uniform and defect-free film surface.Conclusion: The 4% thiourea system showed the best performance with the highest dissolution (55.05%) and DP (624.3), but urea remains the preferred option due to its environmental compatibility and higher crystallinity retention (47.95%). The combined urea/thiourea system, with 49.45% dissolution and DP ≈ 556, exhibited the lowest crystallinity (8.65%), making it suitable for applications requiring an amorphous structure. FTIR confirmed physical dissolution. All three systems are competitive with the Lyocell method and hold great potential for producing biodegradable films, textile fibers, hydrogels, water treatment membranes, and nanocellulose. https://jfwp.ut.ac.ir/article_108609.html Introduction: Hemp (Cannabis sativa L.) is one of the most important non-wood fiber crops. In addition to its medicinal applications, it has attracted considerable attention in the textile, papermaking, bio-based composite, and other industries because of its high-quality bast fibers. Hemp is commonly classified based on cannabinoid composition, particularly the content and ratio of tetrahydrocannabinol (THC) and cannabidiol (CBD), and genetic and molecular approaches have been widely used to distinguish drug and fiber chemotypes. However, the role of anatomical and fiber biometric characteristics in differentiating these types has received far less attention. Because fiber biometric traits directly influence fiber quality and performance in various end products, understanding potential differences between drug and fiber types is important for evaluating their industrial value. Therefore, this study aimed to investigate and compare the biometric characteristics of bast and xylem fibers in type I and type III hemps and to identify the traits contributing to their differentiation.Method: Ten C. sativa genotypes, including five Type I and five type III genotypes, were examined. Type I genotypes were THC-dominant and are generally associated with medicinal and psychoactive uses, whereas Type III genotypes were CBD-dominant and more closely resemble industrial fiber hemp in terms of cannabinoid composition. Three stems were sampled from each type. After separating the bark from the woody core, the samples were macerated using Franklin’s method. Fiber biometric traits of bast and xylem fibers, including fiber length, fiber width, lumen width, and cell wall thickness, were measured. Stem height and bark thickness were also recorded. Data were analyzed using a linear mixed-effects model (LMM), independent t-tests, and Mann–Whitney tests. Principal component analysis (PCA) was used to investigate overall patterns of trait variation, linear discriminant analysis (LDA) was employed to assess the discriminatory power of the measured traits, and Pearson correlation analysis was conducted to evaluate relationships among variables. Comparisons between bast and xylem fibers were performed using paired t-tests.Results: Among the ten examined traits, only bast fiber width and bast fiber wall thickness differed significantly between drug and fiber hemp types. In both cases, drug types exhibited higher values than fiber types. In contrast, no significant differences were observed in bast or xylem fiber length, xylem fiber width, lumen width, xylem fiber wall thickness, stem height, or bark thickness. Principal component analysis showed that the first two principal components explained more than 52% of the total variance, and the relative separation between the two groups was primarily associated with transverse fiber characteristics. Linear discriminant analysis further revealed that cell wall thickness, fiber width, and lumen width, particularly in xylem fibers, were the most important traits contributing to the differentiation of drug and fiber hemp types. Correlation analysis indicated that bast fiber traits and xylem fiber traits were more strongly correlated within their respective tissue systems than between them. Comparisons between bast and xylem fibers showed that bast fibers were significantly longer and had thicker cell walls in both groups, whereas xylem fibers, particularly in fiber hemp types, had larger lumens.Conclusion: The results showed that although drug-type and fiber-type hemp can be distinguished based on certain anatomical characteristics, substantial overlap exists between them, and only a limited number of fiber biometric traits differ significantly. The most important finding of this study is that transverse fiber characteristics, particularly fiber width and cell wall thickness, play a greater role in differentiating drug and fiber hemp types than fiber length, which showed no significant difference between the two groups. Furthermore, the observed differences between bast and xylem fibers reflect their distinct functional roles within the hemp stem. These findings may contribute to breeding programs, the selection of suitable genotypes for industrial applications, and a better understanding of the relationship between fiber structure and performance in hemp. https://jfwp.ut.ac.ir/article_108764.html Introduction: In the high-elevation areas of the Hyrcanian forests, frequent fog events and subsequent fog precipitation occur during the growing season, due to the high humidity of the Caspian Sea and complex topography. In addition to supplying water, fog precipitation plays an important role in ion deposition and the nutrient cycling of the forest. However, changes in the chemical composition of fog precipitation after passing through the oriental beech canopy (Fagus orientalis Lipsky) and its contribution to nutrient inputs to the forest floor have not yet been studied. Therefore, this study aimed to measure the acidity (pH), electrical conductivity (EC), and concentrations of potassium (K+), sodium (Na+), calcium (Ca++), and magnesium (Mg++) in fog precipitation of pure beech stands located at the highlands of the Hyrcanian forests and to compare its nutrient contents with those of open-field rainfall. Materials and Methods: This study was conducted in a pure beech stand in the Hyrcanian forests during the growing season, coinciding with four rainfall events. For chemical analysis, rainwater of four events accompanied with fog were sampled. To achieve this, 50 fog precipitation collectors were installed under the canopy. In addition, 30 open-area rainfall collectors and six stemflow collectors were installed in an open area, and on the trunk of selected trees, respectively. In total, for each rainfall event, five fog precipitation and three open-field rainfall samples were analyzed for pH, EC, K+, Na+, Ca++, and Mg++. After confirming normality with the Shapiro–Wilk test, the data were compared using independent t-tests and Mann–Whitney tests at the 5% significance level. Results: The mean (±standard deviation: SD) pH of fog precipitation (6.5±0.6) beneath the beech canopy did not differ significantly from that of open-field rainfall (6.0±0.3) across the studied events (p > 0.05). However, the EC of fog precipitation in the second (112.4 µs cm-1), and fourth (79.6) events (p < 0.05) was significantly higher than those of open-field rainfall (40.8, and 21.8 µs cm-1, respectively). K+ concentrations in fog precipitation were significantly greater than those in open-field rainfall across all events (p < 0.05), with the highest value recorded in the third event at 21.5 ± 1.6 ppm, while the maximum concentration in open-field rainfall was 4.0 ± 0.1 ppm. Na+ concentration of fog precipitation also exhibited significant differences from that of open-field rainfall in all four events (p < 0.05). Third event showed the maximum concentration of Na+ for both fog precipitation (3.4 ppm ± 0.7) and the open-field rainfall (5.8 ppm ± 0.1). Nevertheless, the Na+ concentration of fog precipitation in the second (1.35 ppm) and fourth (0.55 ppm) events was higher than that of open-field rainfall, which differed from the concentration observed in the first and third events. Ca++ and Mg++ showed significant differences in all events (p < 0.05). The maximum Ca++ concentration was observed in the third event for both fog precipitation (14.5 ppm ± 2.7) and open-field rainfall (24.2 ppm ± 0.5). Likewise, the maximum Mg++ concentration was measured for the third event; 3.1 ppm ± 0.5 for fog precipitation and 5.7 ppm ± 0.1 ppm for open-field rainfall. Conclusion: This study indicated that fog precipitation is a significant source of nutrient input into the ecosystem of upper-montane Hyrcanian beech forests. While fog precipitation did not significantly affect pH, it altered EC and nutrient concentrations. K+ showed a significant increase in fog precipitation, indicating intense leaching, whereas Ca++, Mg++, and Na+ exhibited different patterns. These findings could be instrumental in improving the precision of nutrient input estimations, monitoring the health of beech stands, and predicting the consequences of climate change on water and nutrient cycles in forest ecosystems. https://jfwp.ut.ac.ir/article_109268.html Introduction: Intercropping trees with agricultural crops is considered a modern approach to enhance sustainable land and water productivity while reducing investment risks in wood farming. This applied field study was conducted to evaluate the performance and economic viability of intercropping garden thyme (Thymus vulgaris) with black poplar (Populus nigra '62/154') in Markazi Province, Iran. The primary aim was to improve land and water productivity and to propose a suitable model for sustainable wood farming development in semi-arid regions. Method: The experiment was carried out on a 1500 m² field in the Abbasabad region of Shazand County, Markazi Province, over a five-year period from 2020 to 2024. The study area has a semi-arid climate with an average annual rainfall of 570 mm and a mean annual temperature of 12°C, providing suitable conditions for agroforestry systems. The statistical design was a randomized complete block design (RCBD) with three treatments (pure poplar, pure thyme, and poplar-thyme intercropping) and three replications. In March 2020, 120 one-year-old poplar saplings were planted at a density of 1250 trees ha⁻¹ (4 × 2 m spacing). In autumn 2021, thyme seedlings were transplanted between poplar rows at densities of 20 plants m⁻² (pure cultivation, 25×20 cm spacing) and 10 plants m⁻² (intercropping, 50×20 cm spacing). Irrigation was applied weekly using a drip irrigation system. Poplar growth traits (diameter at breast height, height, and volume) were recorded over five years, while thyme traits (plant height, branch number, canopy diameter, fresh and dry weight, fresh and dry yield) were measured over three harvest years (2022–2024). Thymus vulgaris Dry weight was determined using an oven at 75°C for 48 hours. Data were analyzed using an independent T-test, two-way ANOVA, and Duncan's multiple range test at the 5% significance level. System efficiency was evaluated using Land Equivalent Ratio (LER), Relative Value Total (RVT), Actual Yield Loss/Gain (AYL), and Intercropping Advantage (IA) indices. Additionally, a linear programming model was designed and solved to optimize net profit under constraints of water, land, and labor resources. Results: After five years, mean DBH (12.07 cm), height (8.78 m), and total volume (63.46 m³ ha⁻¹) of poplar trees in the intercropping system were significantly higher (P<0.05) than those in pure poplar cultivation (10.33 cm, 7.81 m, and 42.89 m³ ha⁻¹). The current annual volume increment in intercropping (29.90 m³ ha⁻¹) was 39% higher than in pure cultivation. Annual dry thyme yield was significantly higher in pure cultivation (3765 kg ha⁻¹) than in intercropping (3027 kg ha⁻¹). However, the LER and RVT indices (both >1) and the positive IA values confirmed the economic superiority of the intercropping system. The five-year net profit from intercropping was estimated at 65,120 million IRR ha⁻¹. Moreover, the intercropping system reduced water consumption by 26% compared to pure thyme cultivation and increased economic water productivity (based on gross income per cubic meter of water) by more than 2.6 times compared to pure poplar cultivation. Survival rates for both poplar trees and thyme plants were 100% across all treatments. Conclusion: The poplar-thyme intercropping system is recommended as a superior model for semi-arid regions. This system not only reduces pressure on natural forests and improves water and land productivity, but also generates positive cash flow from the second year (through thyme harvesting), thereby significantly lowering the long-term investment risks associated with wood farming. The results of this study provide a scientific basis for policy-making to promote intercropping systems in similar climatic zones. https://jfwp.ut.ac.ir/article_109335.html Introduction: Acacia tortilis (Forssk.) Hayne is a key species of tree in the scorching hot and dry regions of Iran; its natural habitat is entirely limited to Hormozgan Province. Understanding the quantitative and spatial structure of A. tortilis is crucial for sustainable management, preservation and long-term monitoring of this species. The aim of this paper is to find out the structural properties of the natural stands of this species and create a baseline database for future monitoring of the species in Homeyran and Kong regions of Bandar Lengeh County, southern Iran. Method: For this purpose, two one-hectare sample plots were established, and the following variables were measured for all trees: collar diameter, height, crown area, number of shoots, stand density, natural regeneration, and spatial position. In addition, the spatial and quantitative structure of the stands was assessed using Crancod 3.1 software and nearest-neighbor-based structural indices, including neighborhood distance, uniform angle index, diameter differentiation, height differentiation, diameter dominance, mingling, and structural diversity. Results: According to the results, the number of living trees was (49 and 60 ha⁻¹ in Hamiran and Kong respectively). On the other hand, the density of regeneration was almost three times greater in the case of Homeyran (60 saplings ha⁻¹) than in Kong (22 saplings ha⁻¹), thus indicating a better potential for natural regeneration there. Nevertheless, Kong demonstrated higher values in terms of mean basal area (16.49 cm), tree height (3.58 m), and crown area (42.88 m²) as well as substantially better canopy cover (72.25%) in comparison to Homeyran (39.50%). Among the percent of dead trees Homeyran had many more of them (30.06% versus 8.33% for Kong) suggesting that the site may be less favorable or may have experienced greater environmental stress compared to the latter. The distributions for diameter and height are irregular for both habitats of trees with the biggest number of trees being in the lower and intermediate classes which means that there are more young trees than the old ones. The mean distance between the nearest neighboring tree is equal to 4.83 m and 4.99 m for Homeyran and Kong correspondingly while the nearest neighbor’s index is equal to 8.95 m and 8.79 m for these two stands respectively. Results from the Clark and Evans index showed that Homeyran exhibited a clustered spatial distribution while Kong showed a nearly random pattern leaning towards regularity, and the uniform angle index (0.62 and 0.51) indicated that both stands have an aggregated distribution of trees. Diameter differentiation (0.67 and 0.51) and height differentiation (0.50 and 0.34) are also relatively substantial and pronounced in Homeyran than in Kong meaning that Homeyran is more structurally heterogeneous compared to Kong. The low structural diversity index (0.30 in Homeyran and 0.25 in Kong) and a zero mingling index also confirmed that both stands have a rather simplified, mono-specific and homogeneous structure. Conclusion: The results revealed significant differences in the quantitative and spatial structure of natural Acacia tortilis stands between Homeyran and Kong. Despite exhibiting higher natural regeneration, the Homeyran stand showed greater tree mortality and a more aggregated spatial pattern, whereas the Kong stand was characterized by larger trees, higher canopy cover, and relatively greater stand stability. These findings provide valuable baseline information for the long-term monitoring, conservation, and sustainable management of natural A. tortilis stands in southern Iran. https://jfwp.ut.ac.ir/article_109336.html Introduction: In recent years, many efforts have been made to use natural polymers, especially cellulose and lignin, as renewable and environmentally friendly materials. Lignin with phenylpropane units has great potential for reaction, modification, and use in various applications. This material is recovered in large quantities from the pulp and paper industry every year. Lignosulfonate (LS) is obtained from the sulfite pulping process. It is water-soluble and has a high molecular weight. Lignosulfonate can be used as an emulsion stabilizer, dispersant in oil well drilling, cement compounding and paper coating. Given the importance of lignin, it is essential to investigate the capabilities of lignin in the manufacture of paper and cardboard. Therefore, in this research, the effect of using lignin on the properties of packaging paper was studied. Method: First, long-fiber kraft pulp sheets were crushed into small pieces. The fibers were soaked for 24 hours, then they were defibrated using a laboratory disintegrator. After moisture content determination, the fibers were refined according to the TAPPI standard to achieve freeness about 250 ± 25 ml. Hand-sheets with a basis weight (g/m2) of 60 ± 5 was made from the refined fibers, according to the TAPPI standard. Finally, after making the hand-sheets and before press, the hand-sheets surface was modified by using spray method the sodium hydroxide and then 3% hydrogen peroxide. After cold pressing, the surface of the hand-sheets was sprayed with a lignosulfonate solution. The concentration of the coating solution was 2.5 and 5%. The hand-sheets were fixed by using plate and rings to prevent wrinkles. Then, the strengths, physical and barrier properties of the control and coated papers, including tensile, tear, burst, density, thickness, ash content, surface roughness, water absorption, and air resistance, were investigated. Results: The results showed that the highest tensile, burst and tear strengths index in hand-sheets is related to the modified hand-sheets samples with oxidative surface treatment and coated with lignosulfonate 5%. Also, statistical analysis of the data of the strength's properties indicated that the difference in the data is significant at the 95% confidence level. The highest hand-sheets thickness is related to the hand-sheet sample without oxidative surface treatment and coated with lignosulfonate 2.5%. The highest apparent density of the hand-sheets is related to the sample with oxidative surface treatment and coated with lignosulfonate 5%. Also, the highest ash content and the lowest surface roughness value in the hand-sheet samples are related to the modified hand-sheet sample with oxidative surface treatment and coated with lignosulfonate 5%. The lowest water absorption is related to the control hand-sheet sample and then the sample without oxidative surface treatment and coated with lignosulfonate 5%. The highest value of air resistance in the hand-sheets is related to the sample with oxidative surface treatment and coated with lignosulfonate 5%. Also, statistical analysis of the physical and barrier properties' data of hand-sheets showed that the difference in data is significant at the 95% confidence level. Conclusion: The aim of this research is to coat modified fibers with lignosulfonate and investigate the properties of handmade paper. In this process, hydrogen peroxide was used as an oxidizing agent in an alkaline environment. The results showed that the surface oxidation process caused the creation of functional groups such as COOH on the surface of cellulose fibers. Also, this surface agent increased the reactivity of fibers and lignosulfonate, so that in the samples with the oxidation process, the amount of lignosulfonate absorption and, as a result, the percentage of ash in the paper increased.