WOOD RESEARCH Volume 70, Number 4, 2025
FAUZAN FAHRUSSIAM, ANDI TRI LESTARI, and DINI LESTARI

PHYSICAL PROPERTIES AND NATURAL DURABILITY OF INDONESIAN COMMERCIAL WOODS MODIFIED BY SURFACE CHARRING AND COATING APPLICATION

This study evaluated the characteristics of Indonesian commercial wood species modified through the yakisugi surface finishing technique combined with coating application. Four wood species, teak (Tectona grandis), pine (Pinus merkusii), mindi (Melia azedarach), and mahogany (Swietenia mahagoni), were treated using a mini butane torch to produce charred surfaces either with or without the removal of carbon layers, followed by transparent exterior coating. The treatments were assessed for volumetric swelling, water absorption, and termite resistance through a 12-week graveyard test. Results showed that combining surface charring and coating improved dimensional stability and termite resistance compared to untreated wood. The durability class of teak and pine increased to class II, while mindi and mahogany showed no significant changes. The findings suggest that surface charring combined with coating provides a simple, practical, and effective finishing method to enhance the performance of tropical commercial woods.

WOOD RESEARCH Volume 70, Number 4, 2025
QINYI GU, HONGHAI LIU, and TAO LI

THE STUDY OF SURFACE DENSIFICATION AND TEMPERATE SUPERHEATED STEAM MODIFICATION FOR RUBBERWOOD

This study aimed to develop a high-value wood composite by surface-densification combined with temperate superheated steam modification technology. Rubberwood boards were hot-pressed, the impact of the peak density and thickness of densified layer on the physical and mechanical properties of wood were studied. In this study the platen temperature was kept constant, after hot-pressing the platen cooling phase was omitted replaced by special compression pressure decreasing and steam discharging technic, which could save much energy and time. Superheated steam treatment (190°C for 1.5 h) and conditioning (110°C for 2 h) were recommended for improving dimensional stability and durability. Study results indicated that the surface hardness and modulus of rupture of surface-densified followed by superheated steam modified rubberwood increased by 55.9% and 41.6% compared with non-densified one respectively. Dimensional stability improved substantially. The durability was improved to ‘durable class’ according to GB/T 13942.1-2009.

WOOD RESEARCH Volume 61, Number 2, 2016
Oliver-Villanueva José-Vicente, García-Andújar Enrique, and Gascón-Garrido Patricia

Analysis of durability and dimensional stability of hydrothermal carbonized wooden pellets

Hydrothermal carbonization (HTC) is a chemical pretreatment of wood waste for convert it in biochar by the application of high temperatures and pressures in a reaction time that do not exceed 10 hours. One of the main applications of the HTC biochar is as pellets. In this research durability against fungal decay and dimensional stability associated with relative humidity changes of HTC pellets were analyzed and evaluated. A comparison of these properties between HTC pellets and wooden EN+ pellets has been carried out. HTC pellets are significantly more durable against fungal attack, more dimensionally stable against relative humidity changes and denser than wood pellets, which confers better properties for logistics processes like storage and transport.

WOOD RESEARCH Volume 62, Number 6, 2017
Christian Brischke, Antje Gellerich, HOLGER MILITZ, and Michael Starck

Performance of coated and uncoated horizontal lap-joint members during 20 years of outdoor exposure

Horizontal lap-joint trials were set up using eleven different wood species representing a wide range of natural durability. Coated and uncoated lap-joint specimens as well as non-jointed reference specimens were exposed for up to 20 years and evaluated with respect to decay, formation of cracks and performance of the coating. The tropical wood species Tatajuba, Cedrorana, and Dark Red Meranti performed still very well and also some Europe-grown softwoods with coloured heardwood were still in good shape. The lap-joint set up turned out to be a method that can be used also for determining the durability and performance of untreated naturally durable wood, but suffered from several drawbacks such as time-consuming and costly specimen preparation, difficult to detect onset of decay, and generally long exposure times needed for a reliable durability assessment. Cracks were often the starting point for internal decay, but did not exclusively occur in the lap area.

WOOD RESEARCH Volume 62, Number 5, 2017
Osman Emre Özkan, Ali Temiz, and Hasan Vurdu

Effects of heat treatment on Turkish fir wood properties

In this study, Turkish fir wood (Abies nordmanniana subsp. bornmulleriana) was subjected to two heat treatment process with varying temperatures (150, 180 and 200°C) and durations (2, 4 and 6 h). Some properties of the heat treated Turkish fir wood; mass change, water absorption, volumetric swelling, bending strength, modulus of elasticity (MOE), compression strength parallel to grain, color change and surface roughness have been tested and evaluated by statistical analysis. Consequently, volumetric swelling and water absorption values of the heat treated wood samples reducing. Bending strength, modulus of elasticity and compression strength parallel to grain values were decreased by heat treatment at high temperatures. Additionally, color change and surface roughness values of heat treated wood decreased with weathering compared to those of control samples.

WOOD RESEARCH Volume 64, Number 2, 2019
Seung-Won Oh, In Yang, Dae Hak Park, Soo Min Lee, and Byoung Jun Ahn

Lignin and sugars contents of Liriodendron tulipifera L. sawdust immersed in acidic/alkaline solutions and the fuel characteristics of wood pellets fabricated with the sawdust

This study was conducted to determine the lignin and sugars contents of yellow poplar (YP) sawdust immersed in tap water (TW), sulfuric acid (AC) and sodium hydroxide (AK) solutions. Klason lignin content of TW- and AC-immersed YP sawdust was higher than that of AK-immersed YP sawdust. Glucose showed the highest content among sugars extracted from YP sawdust. Durability of non-immersed YP pellets was the highest, followed by TW-, AC- and AK-immersed YP pellets. YP pellets became more durable by increasing the Klason lignin and xylose contents as well as decreasing the glucose content. Through microscopic observations and quantitative analysis of lignin distribution, lignin content on the surface of non-immersed YP pellets was higher than that of TW-, AC- and AK-immersed YP pellets. In conclusion, there are significant correlations between lignin or sugars contents of YP sawdust and fuel characteristics of wood pellets fabricated with the YP sawdust.