WOOD RESEARCH Volume 70, Number 2, 2025
ZIXING MA, MENG ZHOU, YANGYI WANG, QIYUE WANG, HELAN XU, and XIULIANG HOU

PREPARATION OF ECO-FRIENDLY COMPOSITE PAPER WITH GINKGO LEAF AND BIO-BASED FIBERS

Ginkgo leaf was treated with deep eutectic solvents and then mixed with bio-based fibers, willow catkins or kapok fibers as reinforcing materials to prepare ginkgo leaf composite paper. The effects of the papermaking process conditions and the proportion of ginkgo leaf on the properties of the composite paper were studied. The results showed that the properties of the composite paper were better when the proportion of ginkgo leaf was within the range of 70-90%, with a smooth surface, high strength, and flexibility, which can meet the needs of daily packaging. The higher the proportion of ginkgo leaf, the better the anti-ultraviolet property and the higher the strength. When the proportion of willow catkins or kapok fibers was higher, the water resistance and flexibility were better. Among them, when the proportion of ginkgo leaf was 90%, the ultraviolet protection factor (UPF) could reach 128, showing excellent anti-ultraviolet property. When the proportion of ginkgo leaf was 70%, the water contact angle to composite paper was 144.2°, indicating water resistance

WOOD RESEARCH Volume 70, Number 2, 2025
GANIS LUKMANDARU, MUHAMMAD AKBAR FAQIH, and SIGIT SUNARTA

PULPING AND PAPERMAKING POTENTIAL OF ACACIA AULACOCARPA BENTH WOOD IN INDONESIA

In this study, samples from 27-year-old Acacia aulacocarpa grown on a plantation were examined to determine suitable kraft pulping conditions and properties for paper production. The results showed that A. aulacocarpa had a high basic density of 0.65 g/cm3 and a short fiber length of 0.84 mm. The derived values for Runkel, slenderness, and flexibility ratios were 1.02, 53.01, and 0.48, respectively. Five different active alkali concentrations ranging from 14% to 22%, with intervals of 2% were applied for kraft cooking. The percentages of reject, kappa number, and residual active alkali of black liquor were negatively related to the charge applied in pulping runs. Pulping with 18% active alkali content obtained a screened yield of 51.4% at a kappa number of 34.1. The 20% active alkali cook had the highest mechanical properties of the handsheets. The burst and tear indices met the Indonesian National Standard for leaf (hardwood) bleached kraft

WOOD RESEARCH Volume 70, Number 2, 2025
TSHWAFOELIAS MOTAUNG, ELLA CEBISA LINGANISO-DZIIKE, ZIKHONA TETANA, LEHLOHONOLO FORTUNE KOAO, and SETUMO VICTOR MOTLOUNG

EFFECT OF ALKALINE TREATMENT ON MORPHOLOGY AND BIODEGRADATION OF BAGASSE AND MAIZE CELLULOSE

This study investigates the biodegradation behaviour of cellulose extracted from sugarcane bagasse (SCB) and maize using chemical treatments involving sodium hydroxide (NaOH), sodium chlorite, and buffer solutions (NaOH and glacial acetic acid). The extraction process yielded cellulose at 38.00% from SCB and 45.14% from maize, based on the weight of the raw material. The resulting celluloses were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), confirming their structural and chemical integrity. Biodegradability was evaluated through composting tests, revealing weight losses of 9.08% for SCB cellulose and 29.47% for maize cellulose. The higher degradation rate of maize-derived cellulose suggests enhanced biodegradability

WOOD RESEARCH Volume 70, Number 2, 2025
LI LILI, LIU WENWEN, LUO ZHIYING, LIU DE, YU JIANFANG, WANG XIMING, ZHANG GUO, and ZHEN JING RU

THE EFFECT OF UV ABSORBERS ON THE LIGHTFASTNESS OF DYED VENEERS

To address the problems of fading, surface yellowing and breakage of dyed veneers under prolonged sunlight, this paper uses ash veneers as raw material and new coccine as dye to investigate the effects of bleaching pretreatment, different concentrations (0.5%, 1% and 1.5%) and types of UV absorbers (benzotriazole, TiO2, nano-TiO2) on the color difference value △E of the dyed veneers in the process of aging by natural light and aging by artificial light. The effect of UV absorbers on the color difference △E of dyed veneers during natural light aging and artificial light aging was clarified. The experimental results show that under the natural light condition, the bleached dyed veneer with 0.5% benzotriazole has the lowest △E value, which is about 1.3, and under the artificial UV irradiation condition, the bleached dyed veneer with 1% TiO2 has the smallest △E value, which is about 0.4

WOOD RESEARCH Volume 70, Number 2, 2025
LIN YANG, PUYAN ZHAO, and QIN YIN

STUDY ON THE HYDROTHERMAL TREATMENT OF KILN-DRIED TIMBER OF RED ALDER

This study used red alder (Alnus rubra f. pinnatisecta) and applied humidity control during storage to shorten the health cycle and enhance preservation effects. Orthogonal testing was conducted to assess the impact of humidity control on drying quality and identify optimal conditions. The results showed that: 1) Post-humidity control, most materials exhibited high surface and low core moisture distribution. Surface moisture difference before and after treatment was largest and negatively correlated with moisture increase. Higher temperatures reduced differences at the same treatment duration. 2) Reasonable humidity control significantly improved drying quality: surface moisture remained stable, elastic and mechanical adsorption creep strains decreased, and residual stress was reduced by up to 59.5% after 7 days of humidity and curing compared to room temperature curing. 3) Moisture treatment initially reduced residual stress significantly then rebounded slightly, with stress elimination efficiency generally higher than room temperature. This indicates that humidity control shortens wood storage and curing cycles. 4) Orthogonal test results identified optimal humidity control conditions as 70°C, 85% relative humidity, and 48 h treatment

WOOD RESEARCH Volume 70, Number 2, 2025
LIN YANG, HONGWEI FAN, and JINGTING ZHENG

EFFECT OF SUPERCRITICAL CO2 DEHYDRATION TREATMENT ON THE JUGLANS MANDSHURICA

Conventional kiln drying (CKD) has a long drying period and is easy to cause drying defects. Supercritical CO2 dehydration (SCD) can quickly dehydrate water-saturated wood to above the fiber saturation point without damaging the microstructure and avoiding drying defects. In this study, Juglans mandshurica was treated by SCD to 40% moisture content, then was oven-dried. CKD specimens were used as a control to investigate the effect of SCD treatment on the wood properties of Juglans mandshurica. In the moisture absorption test, the equilibrium moisture content of the SCD and CKD samples was found to be 8.95% and 8.66%, respectively.The final tangential and radial swelling of the SCD samples were 2.5% and 2.03%, respectively, which were 0.1% and 0.24% larger than those of the CKD samples. In the water uptake test, the equilibrium moisture content of SCD and CKD samples was found to be 104.79% and 117.71%, respectively. The final tangential and radial swellings of SCD specimens were 9.38% and 4.6%, which were 2.35% and 1.16% larger than those of CKD specimens. Also, it was confirmed that the extraction content of SCD specimen was reduced, the chemical composition was unchanged, and the open diameter of the pits was about 1.35 μm at 20 MPa/60°C

WOOD RESEARCH Volume 70, Number 2, 2025
TAMAS HOFMANN, LASZLO TOLVAJ, and ZOLTAN PASZTORY

CHEMICAL CHANGES DURING WOOD CUTTING

Scots pine (Pinus sylvestris) and poplar (Populus euramericana) species were chosen for the experiments.Sawdust was made by a circular saw with a rare tooth spacing for producing bigger particles beside the fine fractions. Particles were separated by a vibration separator with the sieve sizes 1 mm, 0.63mm, 0.315 mm, 0.1 mm and 0.063 mm. Infrared reflectance spectra of the particles were measured to determine the chemical changes generated by the cutting procedure.The experimental results showed that the grinding of wood resulted in bond rupture for all ether bond types appearing in the infrared spectrum. The number of conjugated and unconjugated carbonyl groups in the wood was significantly reduced during the cutting procedure. After bond breaks, oxidation and recombination processes occurred generating compounds similar to the aromatic structure of lignin, which were shown by increases in absorption at 1514, 1271 and 1231 cm-1

WOOD RESEARCH Volume 70, Number 2, 2025
CHUN-WON KANG, MASUMI HASEGAWA, KAWANISHI MARIA, and HARADHAN KOLYA

Short notes. INFLUENCE OF WOOD ANATOMY ON THE DISTRIBUTION OF GUANIDINE BASED FIRE RETARDANTS IN FIVE FAST GROWING JAPANESE HARDWOODS

This study investigates the influence of wood anatomy on the distribution of fire retardant chemicals in five fast-growing Japanese hardwood species (Melia azedarach, Toona sinensis, Choerospondias axillaris, Alnus japonica, and Liriodendron tulipifera). Given Japan’s increasing demand for sustainable and locally sourced materials, fire retardant treatments are critical for enhancing fire resistance in fast-growing hardwoods used for construction. Using low vacuum scanning electron microscopy (SEM), we examined the distribution of fire retardants in cross-section, radial section, and tangential sections, comparing the effectiveness in ring-porous versus diffuse-porous species. Results revealed that diffuse-porous species (Alnus japonica and Liriodendron tulipifera) retained higher levels of fire retardants with a more even distribution. In contrast, ring-porous species (Melia azedarach, Toona sinensis, Choerospondias axillaris) showed the highest chemical concentration at the edges.