Softening Behaviour of Indonesian Wood Species

This paper deals with softening behaviour measurements of Indonesian wood species by static bending tests. Wood samples with a size of 110mm (R) x 10mm (T) x 4mm (L) were bending tested in air-dry at 20°C and 65% relative humidity (RH), in water saturation at 20°C, and in water saturation at 80°C to know the decreasing of modulus of elasticity (MOE) and modulus of rupture (MOR) due to moisture content (MC) and both moisture content and temperature (MCT) changes. The wood samples represented Randu (Bombax ceiba. L) as the lowest specific gravity, i.e. 0.27 to Lamtoro (Leucaena glauca (Willd) Benth) as the highest specific gravity, i.e. 0.81. The three-point static bending test was carried out by a mechanical testing machine with a load capacity of 100kgf, loading deflection speed of 5mm/min, a span distance of 80mm at a room with a temperature of 20°C and 65% RH for air-dry wood samples, and that for wet wood samples were conducted in a water bath at 20°C (change in MC) and 80°C (change in MCT), respectively. MOE and MOR increased linearly with specific gravity regardless of wood species. On the other hand, maximum deflection did not correlate with specific gravity for any MCT conditions. The relative MOE and MOR which were calculated in wet 20°C to air-dry were affected from hardly to strongly depending on the wood species. Meanwhile, they decreased extremely when saturated in water at 80°C regardless of wood species. The relative MOE and MOR due to the change in MC or MCT was independent of specific gravity, as well. Furthermore, chemical compositions of the wood species were analysed to clarify the main factors that affected the decreasing of MOE and MOR due to MC and MCT changes. The results showed that the percentage of lignin and hemicelluloses in each wood played an important role in decreasing the static bending properties. Relative MOE and MOR decreased with increasing lignin and hemicellulose contents. It can be concluded that the hygrothermal properties of lignin and hemicelluloses significantly affect the changes of elastic and strength properties of wood in softening conditions.

Antifungal and Antioxidant Activities of Lipophilic Compounds from Swietenia mahagoni (l.) Jacq. Leaves

The investigation on the n-hexane lipophilic extractives of Swietenia mahagoni, alongside the antifungal and antioxidant properties was conducted. The leaf sample was collected from 2- and 3-years-old trees in Perhutani enterprise of Temanggung, Central Java, Indonesia. In addition, the antifungal activity was tested using the white-rot of Phanerochaete chrysosporium, while the antioxidant property involved the DPPH (1,1-diphenyl-2-picrylhydrazyl) method. The results show antifungal of 28.6% and 37.5% growth inhibition in 2- and 3 -years-old leaf, respectively, while 21.7% and 25.4% antioxidant activity were also recorded. Furthermore, the GC-MS results showed the domination of S. mahagoni leaf by fatty acids and hydo-carbons, while the terpenoids and steroids were in minor quantities. These components possibly exhibit growth inhibitory and antioxidant effects against P. chrysosporium and DPPH radicals, respectively.

Thermal Conductivity of Teak Wood from Thinned Stands

Wood has been utilized as a heat conductor or insulator. Hence, this research aims to discover the thermal conductivity of teak wood using thinned stands from the Perhutani plantation forest. The samples obtained had varying moisture content and fiber direction, and were of distinct tree ages, at 12, 15, 20, 25, and 60 years. This result show that the thermal conductivity in air-dry conditions and fiber saturation points were 0.116 to 0.128 and 0.338 to 0.151 in W/Mk, respectively. The analysis of variance showed that the thermal conductivity of teak wood was affected by the interaction of fiber directions and moisture content but not significantly by tree age. Also, there was a weak relationship found between thermal conductivity and specific gravity in air-dry conditions and longitudinal direction.

Recent Research Activities in Solid and Liquid Bioenergy from Lignocellulosic Biomass

The increase in energy demand, the lack of petroleum resources, and concern over global climate change have placed great emphasis on the development of new alternative energy technologies that can be used to replace fossil transportation fuels (Himmel et al. 2007; Labbe et al. 2008; Lee et al. 2009a,b,c; Teramoto et al. 2008, 2009). In this context, many countries have initiated extensive research and development programs for bioenergy. Bioenergy can be classified into three kinds of solid, liquid, and gas bioenergy. For the effective production and utilization of these three types of bioenergy, different technologies are required (Figure 1). Lignocellulosic biomass, such as wood and agricultural residues, are widely distributed and easily accessible at relatively low costs. Of these, wood has the benefit of having a higher energy content per volume, lower ash content, and nitrogen content. In this review, recent research trends and advances in bioenergy from lignocellulosic biomass will be summarized from the author’s point of view.

Inorganic Elements of Mangium Stem (Acacia mangium Willd) from Different Provenanc

This study aimed to investigate the ash content and concentrations of inorganic elements present in the stem of Acacia mangium. The tree samples (24 years) were collected from five different provenances (Sidei, West of Morehead, Daintree, Ellerbeck, and El Arish). Meanwhile, the disc samples were obtained from the trunk of each tree on the lower parts. The samples were collected from four radial positions (bark, sapwood, outer heartwood, inner heartwood), and the ash and insoluble acid contents were determined. Furthermore, the concentration of 5 elements (Ca, Mg, Fe, Mn, K, and Na) was measured by Atomic Absorption Spectrophotometry (AAS). The interaction of provenance and radial position factors affected ash and potassium contents. Also, acid insoluble ash and calcium contents showed a provenance factor effect. The barks obtained from the tree samples contained the highest concentrations of ash content and most of the elements. The wood and bark of El-Arish provenance showed the lowest (0.50~0.72%) and highest levels (4.75%) of ash content respectively. Furthermore, the highest amount of insoluble acid ash (3075 ppm) and calcium (4513 ppm) content was also measured in samples of El-Arish provenance, and radial position factor was a significant source of variation for Ca, Mg, Na, and Mn concentrations. Except Mg, the inner and outer portions of the heartwood mostly showed no significant difference in unprecedented element concentrations. Ash content was positively correlated with Ca in sapwood (r=0.39) and Mn in bark (r=0.54). In addition, moderate correlations were observed between Mg and Ca in heartwood (r=0.63) and bark (r=0.54) tissues. For ash and silica content, the comparatively low concentration on samples from El-Arish provenance are good options to improve wood quality for breeding programs.

Chemical Properties of 15-year-old Teak (Tectona grandis L.f) from Different Seed Sources

Fifteen year-old teak wood samples planted in Ciamis FMU (Perhutani Enterprise) were evaluated for their chemical properties. Three seed sources such as conventional seed, clone, and superior wood and radial positions namely sapwood, outer heartwood, and inner heartwood were the observed factors. The specimens were taken from the bottom parts of their sources. Completely randomized design was used. Cell wall components were analyzed by various gravimetric methods.Analysis of variance and Duncan’s test were performed for data analysis. The results showed that no significant difference in the quantity of cell wall components (cellulose, hemicellulose, and lignin), extractives (ethanol-toluene and hot-water solubles), ash, and silica content among the seed sources. Superior teakwood or Jati Plus Perhutani, which has the highest growth rate (2.1~3.6 cm/year) among others, showed a comparative higher average pH values (7.08~7.38) and solubility in 1% NaOH (17.22~17.83%) than other sources. Radial factors significantly affected ethanol-toluene extractive and lignin content. The ethanol-toluene extractive had the highest content (9.30~11.54%) at the outer part of heartwood while lignin content was the lowest (28.12~30.10%) in the inner part. The result indicated some good characteristics of young teak trees compared to the mature ones in relation to wood processing.

The Natural Durability and Drying Properties of Ganitri Wood (Elaeocarpus sphaericus Schum)

Ganitri (Elaeocarpus sphaericus Schum.) is a fast-growing species that was majority planted in community-based forets in Java. This research aimed to evaluate the natural durability and drying properties of ganitri wood, hence the best uses of the wood can be achieved. The wood durability was tested in laboratory and field scales based on SNI 7207:2014 and ASTM D 1758-02 standards respectively, while the wood treatibilty evaluation used soaking method with 5% borax preservative. The wood drying property was assessed through oven drying at 100°C temperature based on Terazawa method. The resistance of the wood against subterranean termites Coptotermes curvignathus is classified as durability class IV. Ganitri wood was very easy to be preserved with the cold soaking method. Boron retention in ganitri was 22.87 kg.m-³, while its penetration was 27.80 mm or 94.24%. Ganitri had rather poor drying properties, which was prone to surface check. The proper drying for ganitri wood was suggested using initial and final temperatures 53°C and 83°C, respectively, while the initial and final relative humidity were 85% and 30%.

Analysis on Chemical Components of Woods to Predict Ethanol Production Values

This paper deals with analysis on chemical components of woods to predict ethanol production values. The aim is expected to give a reliable value of ethanol production, eliminating the effort needed to directly measure this ethanol production from each wood species. Since the data of wood chemical components is widely available, this result will be valuable in determining a potential use of a wood species as bio-ethanol feedstock. Saccharification and fermentation processes by enzymatic hydrolysis were applied for xylems derived from49 branch trees of Cibodas, 32 branch trees of Purwodadi, and 19 branch trees of Bali Botanical Gardens in Indonesia. Three major wood components were analysed, i.e. cellulose, hemicellulose, and lignin. The results show varied relationships between ethanol production and chemical components of wood. The content of cellulose in wood was not exactly related to its ethanol production. This trend was also occurred for the relationship between hemicellulose and ethanol production. However, lignin content in woods gave an expected trend where the less lignin content, the higher the ethanol production.Furthermore, the ratios of cellulose-hemicelluloses and cellulose-lignin have been quantified. The result showed that the celullose-lignin ratio can potentially be used to predict the value of ethanol production which is expressed by linear regression y = 0.0616x + 0.8341; where R² = 0.4127, x = ethanol production and y = cellulose-lignin ratio. Gymnostoma sumatranum with cellulose content of 43.8% and lignin content of 24.1% (celullose-lignin ratio of 1.8) has actual ethanol production of 12.1 mg/100mg wood meal, compared to 15.7 mg/100mg wood meal resulted from above equation. Therefore, by using its cellulose-lignin ratio, the woods having high ethanol production can be screened from literatures.

Fuelwood Characteristics of Five Species Grown in Merauke Forest

Papua has a large area of production forests, such as in Merauke. These forests provide great benefits for the pulp and wooden industries, which generate a large amount of biomass waste. Therefore, this study aimed to investigate the proximate analysis, specific gravity, calorific value, and Fuelwood Value Index (FVI) of wood and bark of five species, namely Acacia mangium Willd, Acacia crassicarpa A. Cunn, Eucalyptus pellita F. Muell, Melaleuca viridiflora Sol. Ex Gaertn, and Lophostemon suaveolens Sol. Ex Gaertn. The calorific value ranged from 4,066 to 5,435 cal/g, while the FVI values ranged from 4.04 to 76.41. The highest calorific value was observed in the bark of Melaleuca viridiflora, while the highest fuelwood value index was observed in Eucalyptus pellita wood. Furthermore, the calorific value of wood was higher compared to the bark in all species. There was no significant correlation between specific gravity, calorific or FVI value. It is noticed that a strong correlation (r = -0.92*) was observed between the calorific value and volatile matter in the bark. Based on the proximate analysis results, only the moisture content level was significantly correlated with the calorific value of wood or bark.

Mechanical Properties of Compressed Wood with Various Compression Ratios

This paper investigates five groups of compressed wood (CF), four of them made from compressed Japanese cedar with four different compression ratios (CR) of 33%, 50%, 67% and 70% and one without compression (control). The specimens were conditioned in relative humidity (RH) of 60% with moisture content (MC) of 12%. Mechanical properties tested were shear modulus in LR, LT and RT planes by single cube test method, Young’s modulus in the L, R, T directions and poisson’s ratios in all planes. Results showed that in comparison with control specimen, the average improvement on density with CR improvement were 25%, 75%, 175% and 261% corresponding to CRs of 33%, 50%, 67% and 70% respectively. It was also found that Young’s modulus in the L and T directions increased significantly with the increase of CR. Shear modulus of RT plane increased with the rise of CR. Poisson’s ratios tended to decrease with increasing compression ratio of CW.