Thermal Compression Effect on Several Properties of 8-Year-Old Waru Gunung (Hibiscus Macrophylllus) Wood

Abstract

The study aimed to investigate the effect of thermal compression on the properties of 8-year-old waru gunung wood. Wood specimens with the dimension of 25 mm100 mm150 mm in thickness, width and length, respectively were heated at 180 ˚C and 200 ˚C for 4 h. During the heating process, the specimens were subsequently compressed at 2.452 N mm−2 for 40 mins at each temperature. Changes in the wood chemical structure were examined using the pyrolysis-gas chromatography-mass spectrometry, the wood physical properties were tested according to ASTM D143-94, the wood surface hardness was tested using a Universal Testing Machine and the wood discoloration was examined using the CIELab method. The changes in crystallinity degree was examined using x-ray diffraction and cell structure were collected as supporting data. Results showed that the thermal compression at 180 ˚C and 200 ˚C caused severe degradation on the specimen carbohydrate but less for lignin. The sum effect of thermal compression on the specimens also consecutively increased the density by 34.24% and 41.87% and surface hardness by 52.78% and 63.09% and decreased the swelling thickness by 38.54% and 47.03% and the equilibrium moisture content by 36.53% and 38.59% at 180 ˚C and 200 ˚C, respectively. Thermally compressed specimens also had darker colours, glossier surfaces and smoother texture compared to non-thermally compressed specimens.

Wood Physical and Mechanical Properties of Clonal Teak (Tectona grandis) Stands Under Different Thinning and Pruning Intensity Levels Planted in Java, Indonesia

“…The Implementation of girdling as a pre-harvest treatment could be an option for alleviating the inimical effect of high MCG on the thinned clonal teak stands. Girdling is a pre-harvest treatment that reduces the moisture content of the standing tree's stem as a result of photosynthates flow impediment from reaching the root system by creating inward incisions encircling the stem from the periphery to the cambium zone (Basri et al, 2015;Noel, 1970). This method has been practiced for decades as part of the teak stand management in India, Indonesia (Java), Myanmar, and Thailand (Strugnell, 1932).…”

“…This method has been practiced for decades as part of the teak stand management in India, Indonesia (Java), Myanmar, and Thailand (Strugnell, 1932). Previous studies reported that several months of girdling in young ages trees was effective in reducing MCG by more than 50% from the initial MCG in teak (Rini, 2013), Acacia mangium (Basri et al, 2015), and various coniferous species (Laurila et al, 2014). Therefore, it was suggested to conduct girdling as a pre-harvest treatment when practising thinning and pruning regimes on the clonal teak plantation to alleviate the adverse impact of high MCG on clonal teak wood from both silvicultural practices.…”

“…The application of further treatment could be considered when both silvicultural practices were implemented. Girdling could also be applied as a pre-harvest treatment because of its ability to reduce TS, RS, and T/R-ratio significantly, indicating increased wood dimensional stability (Basri et al, 2015).…”

“…To diminish the adverse impact of high MCG and wood shrinkage parameters, additional pre-harvest treatment must be incorporated as an integral component of clonal teak plantation management when thinning and pruning regimes were implemented. Girdling is one of the pre-harvest treatments that have been scientifically proven to reduce MCG and wood dimensional shrinkage of the stands in various species (Basri et al, 2015;Laurila et al, 2014;Rini, 2013). Therefore, it is suggested that girdling has to be incorporated when thinning and pruning regimes will be applied in managing genetically-improved clonal teak plantations.…”

Problems encountered in log depots and measures to combat them: A review

“…For these reasons, many properties of wood (such as resistance to decay) can be affected (Taylor and Cooper 2007). A longer girdling period decreases the degree of deformation during drying and also increases wood density (Basri et al 2015).…”