Wood Shrinkage Research Articles

Study on Collapse-Shrinkage Characteristics in Plantation-Grown Eucalyptus Wood under Continuous and Intermittent Drying Regimes

Collapse-type shrinkage is the greatest obstacle to prevent planted eucalypts from being used for solid wood products. In order to make the suitable drying schedules for high effective utilization of eucalypt wood, the total shrinkage and collapse on two species of difficult-to-dry E. urophylla and E.grandis wood under continuous and intermittent drying regimes were measured. The results show that total shrinkage and collapse in both eucalypts exhibited higher values for continuous drying than intermittent drying. With increasing drying temperature, total shrinkage and collapse increase in both drying regimes, while the increasing magnitude of both parameters becomes apparently larger for continuous drying than intermittent drying regime, in particular higher temperature condition. Properly elevating drying temperature to make up for the intermittent-waiting time may be allowed for intermittent drying regime. Drying duration at each intermittent drying period has a greater effect on total shrinkage and collapse of eucalypt wood. When more than a drying duration of 6 hours at an intermittent drying period is used, the differences in shrinkage and collapse between both drying regimes are very slight. Intermittent duration at an intermittent drying period has a comparatively larger effect on total shrinkage and collapse. Accordingly, we may draw a conclusion that intermittent drying regime is very likely to be a potential drying one suitable for collapse-prone lower-density plantation-grown eucalypt wood.

Collapse-Type Shrinkage’s Characteristics in Both <i>Eucalyptus urophylla</i> and <i>E.cloeziana</i> Wood under Heat-Treatment Conditions

In order to explore the formation process of collapse-type shrinkage of eucalypt wood, the collapse-shrinkage properties in Eucalyptus urophylla and E.cloeziana wood under different heat-treatment conditions were systematically investigated by using frozen drying, and simultaneously creative assessments on their collapse-type shrinkage process were conducted based on the novel concepts of both transient collapse and maximum transient collapse advanced for the first time. The results indicated that, for lower-density E.urophylla, total shrinkage and residual collapse under both heat-treatment regimes increased with increasing temperature. As compared to intermittent heat treatment, the above two indices at three levels of temperatures in continuous heat treatment displayed relatively larger values, and exhibited down-open-parabola type; For higher-density E.cloeziana, only higher collapse phenomenon in the part near to the pith were observed, and similar to E.urophylla, while almost slight and /or no collapse occurs in the middle heartwood and sapwood, and shrinkage and collapse in continuous heat treatment is slightly larger than those in intermittent heat treatment, and both shrinkage and collapse take on up-open-parabola type. Trends of radial variation of both parameters for both species in continuous heat treatment were consistent with those in intermittent heat treatment. It can be speculated that the mechanism of the difference in collapse-type shrinkage characteristics between two heat-treatment patterns are that the more types of cells and the more number of cells participated in the collapse development, and the more transient collapse, especially maximum transient collapse, is transformed into the permanent set to develop the residual collapse for continuous heat treatment than the intermittent heat treatment. Therefore, it is very crucial for lower-density susceptible-collapse eucalypt to manage to prevent maximum transient collapse from being transformed into permanent set in the process of drying.

The influence of material properties on the amount of twist of spruce wood during kiln drying

The development of twist in Norway spruce boards (Picea abies Karst.) during normal temperature kiln drying was researched. Tangentially oriented boards were sawn from diametrical radial planks, from which the basic wood properties, i.e. linear shrinkage and grain angle, were determined. The unrestrained boards were kiln dried using a selected drying schedule. During the controlled drying process the moisture content (MC) and twist of the boards were measured. Twist was generally induced by the shrinkage of wood below the fibre saturation point, and increased in proportional to the decrease in MC. The earlier appearance of twist, with regard to MC and drying time, was confirmed in the case of boards sawn from the central part of logs. The final twist amounted to between 10 and 20°/m in the case of boards close to the pith, and decreased to less than 4°/m in the case of boards sawn at a radius of 70 mm from the centre of the logs. Ring curvature had the highest impact on the final twist of the dried boards, followed by grain angle and tangential shrinkage.

Wood stiffness and strength as selection traits for sawn timber in Acacia auriculiformis

Acacia auriculiformis A. Cunn. ex Benth. is an important planting tree species, but little attention has been paid to its wood properties, such as shrinkage, stiffness, strength, and basic density, which are important for use in structural and appearance-grade timber applications. Here we report the genetic variation in static bending stiffness and strength of wood in a 5½-year-old clone trial in southern Vietnam and the genotypic correlations among these traits and tree diameter, wood shrinkage, and basic density. There was significant variation in stiffness and strength among 40 randomly selected clones. Clonal repeatability (H2) was high for stiffness and moderate for strength. There was no consistent pattern of difference between heartwood and sapwood for the estimates of H2 for stiffness and strength, whereas the estimates of H2 were lower for heartwood density than for sapwood density. Diameter showed a significant negative genotypic correlation with stiffness but a nonsignificant correlation with strength. Genotypic correlations between density and stiffness, and density and strength, were positive, but only the latter was significant. Stiffness and strength were not significantly correlated with wood shrinkage. There is potential to simultaneously improve tree growth, wood basic density, and the mechanical properties of juvenile wood of this species.

The within-tree variation in wood density and shrinkage, and their relationship in Populus euramericana

The patterns of wood density and shrinkage in different directions in 22-year-old Populus euramericana trees from one clone were studied in an experimental plantation in Iran. Sample disks were taken from each tree to examine wood density and shrinkage variation from pith to bark at 5%, 25%, 50%, and 75% of total tree height. The results indicate that radial position and height significantly affected all wood physical properties. Within-tree wood density and shrinkage varied at each height level, decreasing along the stem from the base upwards. Moreover, within the samples, at the same height level wood density and shrinkage in the radial direction increased from the pith outwards. Regression analysis showed that longitudinal, radial, tangential, and volumetric shrinkage each had a significantly positive correlation with wood density.

Fiber Saturation Point of Several Indonesian Lesser Known Species

Fiber saturation point (FSP) of several Indonesian commercial wood species was studied comprehensively. Five wood species namely sengon (Paraserianthes falcataria), gmelina (Gmelina arborea) , nangka (Arthocarpus heterophyllus), manii (Maesopsis eminii), and mangium (Acacia mangium) from plantation areas closed to Bogor Agricultural University (IPB) campus were used as the sample. From each species, one normal tree was selected then cut, and one hundred and twenty small healthy blocks of (1 x 1 x 0.5) cm 3 were extracted randomly and utilized for specific gravity (SG) and wood shrinkage -green to air dry and to oven dry conditions- measurement. FSP was then measured as a ratio of total volumetric shrinkage and the SG. It was showed that FSP was affected by species namely extractive content. In all species studied, average value of FSP was below 30%. FSP of sengon, gmelina, nangka, manii, and mangium in average was 26.41%, 16.92%, 14.49%, 22.31%, and 23.94%, respectively.

Rapid prediction of shrinkage and fibre saturation point on teak (Tectona grandis) wood based on near-infrared spectroscopy

• Dimensional stability, along with the natural durability and colour of the wood, is one of the most important characteristics of teak used as timber. However, it is very time-consuming to take measurements of this kind. For the purposes of selection for the production of improved varieties, the number of samples to be measured rapidly exceeds the capacity of a traditional laboratory. • Near-infrared spectroscopy, based on a set of reference data, is a tool enabling many of the chemical properties of wood to be predicted and the number of laboratory measurements to be reduced exponentially. The issue here is a question of checking the effectiveness of NIRS tool to build models and predict the shrinkage and fibre saturation point of teak wood from Togo. • The results show the possible use of NIRS to measure the dimensional stability of teak wood and that it is appropriate to choose the type of wood and type of surface to be measured by NIRS. The best prediction models for radial and tangential shrinkage and fibre saturation point give R 2 values of 0.72, 0.83 and 0.87 respectively with ratios of performance deviation of 1.8, 2.4 and 2.8. • Consequently, after verification on other sets of teak samples, which may or may not be included in the prediction model, NIRS can be used to predict shrinkage and fibre saturation point values accurately for a large number of samples, making it possible to include these characteristics in the selection criteria for classifying wood and high throughput phenotyping.

Predicting Microfibril Angle in Eucalyptus Wood from Different Wood Faces and Surface Qualities Using near Infrared Spectra

The microfibril angle (MFA) of crystalline cellulose in the wood cell wall along the stem axis has major effects on stiffness and longitudinal shrinkage of wood and is of key importance to timber quality. The aims of this study were: (1) to develop partial least square (PLS) regression models for microfibril angle (measured on tangential sections by X-ray diffraction) based on NIR spectra measured on tangential and on radial surfaces; (2) to develop PLS regression models for MFA based on radial NIR spectra collected from wood surfaces of different quality; and (3) to verify the reliability of these PLS-R models by external validations. T values were recorded by X-ray diffraction on tangential sections while NIR spectra were taken on tangential and radial wood surfaces. PLS-R calibrations for MFA based on tangential NIR spectra were better ( r2p = 0.72) than those using radial NIR spectra ( r2p = 0.64). The key role of the chemical components and the effect of surface quality of wood on NIR spectroscopy calibrations are discussed. Considering the differences between experimental conditions, these findings showed the potential of the NIR-based models for predicting MFA in Eucalyptus wood, even using spectra taken from different wood faces and surface qualities.

Modeling Shrinkage Response to Tensile Stresses in Wood Drying: I. Shrinkage-Moisture Interaction in Stress-Free Specimens

This article reports on the wood shrinkage during drying in relationship with the temperature and moisture content. All tests were performed perpendicular to the grain on small clear wood specimens of green Western hemlock while drying at 40, 60, and 80°C to 17, 11, and 5% final moisture contents. Overall, wood dimensional changes and moisture loss phenomena were successfully analyzed and interpolated. The shrinkage strain followed a nonlinear pattern with the moisture loss being the driving force and exhibited good correlation with the square value of moisture content in tangential, and linear moisture values could be used to describe shrinkage in radial direction. Both shrinkage intersection points and end of capillary water values increased with temperature; the distinction between the two values could not be made at all times. A nonlinear function containing two regression coefficients (α and β) was found to be a good interpolation of the moisture loss experimental data. Further analyses revealed that β is independent of both target moisture content and temperature, whereas α appears to be influenced by both variables. The correlation between shrinkage and moisture loss rate is intended to be used as a stress prediction tool.

Paper by M. Ivković, W. J. Gapare, A. Albarquez, J. Ilic, M. B. Powell and H. X. Wu “Prediction of wood stiffness, strength and shrinkage in juvenile wood of radiata pine”, in Wood Science and Technology 43(3–4); 237–257 (2009)

Paper by M. Ivković, W. J. Gapare, A. Albarquez, J. Ilic, M. B. Powell and H. X. Wu “Prediction of wood stiffness, strength and shrinkage in juvenile wood of radiata pine”, in Wood Science and Technology 43(3–4); 237–257 (2009)

Shrinkage processes in standard-size Norway spruce wood specimens with different vulnerability to cavitation.

The aim of this study was to observe the radial shrinkage of Norway spruce [Picea abies (L. Karst.)] trunkwood specimens with different hydraulic vulnerability to cavitation from the fully saturated state until the overall shrinkage reaches a stable value, and to relate wood shrinkage and recovery from shrinkage to cavitations of the water column inside the tracheids. Radial shrinkage processes in standard-size sapwood specimens (6 mm x 6 mm x 100 mm; radial, tangential and longitudinal) obtained at different positions within the trunk, representing different ages of the cambium, were compared. Cavitation events were assessed by acoustic emission (AE) testing, hydraulic vulnerability by the AE feature analysis and shrinkage was calculated from the changes in contact pressure between the 150 kHz AE transducer and the wood specimen. Two shrinkage processes were observed in both juvenile (annual rings 1 and 2) and mature wood (annual rings 17-19), the first one termed tension shrinkage and the second one cell wall shrinkage process, which started when most of the tracheids reached relative water contents below fiber saturation. Maximum tension shrinkage coincided with high-energy AEs, and the periods of shrinkage recovery could be traced to tension release due to cavitation. Juvenile wood, which was less sensitive to cavitation, had lower earlywood tracheid diameters and was less prone to deformation due to tensile strain than mature wood, showed a lower cell wall shrinkage, and thus total shrinkage. Earlywood lumen diameters and maximum tension shrinkage were strongly positively related to each other, meaning that bigger tracheids are more prone to deformation at the same water tension than the smaller tracheids.

Wood shrinkage: influence of anatomy, cell wall architecture, chemical composition and cambial age

The influence of microfibril angle (MfA), density and chemical cell wall composition on shrinkage varied between the longitudinal and tangential directions as well as between wood types, namely compression wood (CW), mature wood (MW) and juvenile wood (JW). At the same MfA, CW exhibited a lower tangential shrinkage than JW, indicating the influence of the chemical composition on wood shrinkage. The chemical composition measured via FTIR micro-spectroscopy has been shown in conjunction with density to be an alternative to MfA data for shrinkage predictions. This was particularly true for wood of young cambial age for which the MfA did not correlate to shrinkage. The results indicate a possibility to reduce distortion of sawn timber by segregation using infrared (IR) and X-ray in-line measurements.

Review of growth and wood quality of plantation-grown Eucalyptus dunnii Maiden

Summary Forests NSW manages Eucalyptus plantations on the north coast of NSW, Australia, for high-value timber production. One species increasingly being planted both in Australia and overseas is Eucalyptus dunnii Maiden. For a species to be considered suitable for forestry, criteria to be met include successful establishment, growth and suitability for end use, be that pulp, solid wood or veneer production. Historic data from E. dunnii plantations aged from 3 to 34 y were reviewed. Growth and wood quality using a range of non-destructive and destructive measurements are reported. Eucalyptus dunnii typically grew equally well as some alternative species, although species ranking was affected by the growing site. Eucalyptus dunnii produced high-quality wood chips with average pulp yield from three NSW plantations aged 8–10 y of 53% and 265 kg m−3. This yield is comparable with that of 10-y-old E. globulus plantation material from Tasmania. Wood density increased with tree age from about 500 kg m−3 at age 10 y to 600 kg m−3 at age 25 y, and more slowly beyond that age. Many solid-wood quality traits such as hardness and strength could be positively correlated with both tree age and basic density. This has implications for the timber industry as it is intended that plantation trees will be harvested at younger ages than native forest trees, but wood quality in such younger material may not satisfy minimum product performance requirements. However, trees selected for higher density achieved strength group ratings at age 9 y that would normally be achieved at age 25–30 y. It is not known if similar improvements can be made in other wood quality traits. Quality traits requiring further examination are growth stresses and end splitting of logs, and shrinkage of sawn timber. Collapse (reversible shrinkage) and non-reversible shrinkage are positively related to wood density, but a greater concern is the high ratio of tangential shrinkage compared to radial shrinkage. This ratio, which can be 2.5 or greater in E. dunnii, leads to excessive distortion in sawn material. It may be possible to reduce overall wood shrinkage and the ratio of tangential to radial shrinkage, as well as other unfavourable wood quality traits, through genetic selection as these traits in related eucalypts (e.g. blackbutt, E. pilularis) are heritable.

Estimation of Drying Stress in a Longitudinally Hollowed Boxed-Heart Lumber Using Finite Element Method

The drying stress in a longitudinally hollowed boxed-heart lumber was estimated using a linear finite element method (FEM). The drying stress due to the anisotropic shrinkage of wood was estimated with the aid of thermal stress analysis in orthotropic materials. The tensile drying stress due to the anisotropic shrinkage of wood concentrated at the middle of wider side surface of the hollowed lumber. In the case of the lumber whose pith was set off from the center of the cross section, higher tensile stress was found at the side surface nearer to the pith than at the other surface. This stress concentration was relieved by allocation of the hollow at the position of the pith.

Genetics of Shrinkage in Juvenile Trees of Pinus radiata D. Don From Two Test Sites in Australia

Abstract To examine the genetic control of wood shrinkage (radial, tangential and longitudinal) in juvenile wood of radiata pine (Pinus radiata D. Don), we assessed samples collected at breast height in two related progeny tests of age 8 and 9 years, established at two different sites in Australia. Green to oven-dry tangential and radial shrinkage for the outer-rings was similar at both sites. Similarly, mean longitudinal shrinkage for the outer-rings was similar at both sites (0.3%, ranging from 0.1 to 1.9 at Flynn and 0.4%, ranging from 0.02 to 1.6, at Kromelite). Mean longitudinal shrinkage for the inner-rings was 4 times greater than that of the outerrings at both sites. The magnitude of the gradient of longitudinal shrinkage from pith to bark (0.001 to 2.9%) is large enough to cause distortion problems including twist and warp, during drying of sawn boards. These values also suggest that shrinkage in the juvenile core of radiata pine is of major economic importance and therefore should be improved either through genetics or silviculture. Individual-tree narrow-sense individual heritability for tangential and radial shrinkage in the outer-rings (4-6) was moderate at Flynn (0.24 ± 0.09 and 0.26±0.07, respectively). There was a lack of significant genetic variation for longitudinal shrinkage in the outer-rings but significant genetic control for the inner-rings (1-2) (h2 = 0.26 ± 0.07). More samples per family are required to detect significant genetic variation for shrinkage traits than other traits due to higher background variation in sampling and measuring shrinkage traits relative to other wood quality traits such as density, microfibril angle (MfA), spiral grain and modulus of elasticity (MoE).

Prediction of wood stiffness, strength, and shrinkage in juvenile wood of radiata pine

Development of optimal ways to predict juvenile wood stiffness, strength, and stability using wood properties that can be measured with relative ease and low cost is a priority for tree breeding and silviculture. Wood static modulus of elasticity (MOE), modulus of rupture (MOR), radial, tangential, and longitudinal shrinkage (RS, TS, LS), wood density (DEN), sound wave velocity (SWV), spiral grain (SLG), and microfibril angle (MFA) were measured on juvenile wood samples from lower stem sections in two radiata pine test plantations. Variation between inner (rings 1–2 from pith) and outer (rings 3–6 from pith) rings was generally larger than that among trees. MOE and MOR were lower (50%) in inner-rings than in outer-rings. RS and TS were higher (30–50%) for outer-rings than inner-rings, but LS decreased rapidly (>200%) from inner-rings to outer-rings. DEN had a higher correlation with MOR than with MOE, while MFA had a higher correlation with dry wood MOE than with MOR. SLG had higher significant correlation with MOE than with MOR. DEN and MOE had a weak, significant linear relationship with RS and TS, while MOE had a strong negative non-linear relationship with LS. Multiple regressions had a good potential as a method for predicting billet stiffness (R 2 > 0.42), but had only a weak potential to predict wood strength and shrinkage (R 2 < 0.22). For wood stiffness acoustic velocity measurements seemed to be the most practical, and for wood strength and stability acoustic velocity plus core density seemed to be the most practical measurements for predicting lower stem average in young trees.

Shape recovery of collapsed archaeological wood ware with active alkali-urea treatment

Most wooden remains from archaeological sites in waterlogged burial environments are found to be intact without shrinkage despite centuries of storage. However, waterlogged wooden remains are subject to shrinkage damage and some even lose up to 80% of their original volume when exposed to air. The shrinkage of archaeological waterlogged wood with the loss of a large part of the initial volume of the wooden remains has been considered irreversible. Here we show that “active alkali-urea”, serving as a re-swelling chemical agent, can almost fully restore the collapsed archaeological wood to its original shape. The restoration experiment showed that the main reason for the restoration of collapsed wood is that the collapsed cell cavity almost completely recovered its original shape during active alkali-urea treatment. We suggest that the shape of collapsed archaeological wood remains can be fully recovered, and that the collapsed archaeological wood can thereby recover its valuable cultural properties.

Genetic variation in Eucalyptus nitens pulpwood and wood shrinkage traits

Eucalyptus nitens plantations are generally established for pulpwood production but an increasing area is being managed for solid wood. Genetic variation in, and correlations among, three Kraft pulpwood traits (diameter at breast height, basic density and near-infrared-predicted cellulose content) and three 12-mm wood-core shrinkage traits (recoverable collapse, net shrinkage and gross shrinkage) were examined, utilising data from two 9-year-old first-generation progeny trials in Tasmania. These trials contained approximately 400 open-pollinated families (over 100 of which were sampled for wood properties) representing three central-Victorian E. nitens races. Significant genetic variation at the race and/or within-race level was identified in all traits. Within races, relative levels of additive genetic variation were higher for shrinkage traits, although narrow-sense heritabilities were lower and the expression of genetic variation less stable across sites than for other wood property traits. Heterogeneous intertrait genetic correlations were identified across sites between growth and some wood property traits. However, where significant, genetic correlations indicated that within-race selection for growth would adversely affect core basic density and all core shrinkage traits. Furthermore, results based on cores suggested that within-race selection for higher basic density would favourably impact on cellulose content and collapse but selection for either higher basic density or cellulose content would adversely affect net shrinkage. Most within-race genetic variation in gross shrinkage appeared to be due to genetic variation in collapse. The implications of these results for sawn timber breeding will depend on the strength of genetic correlations between core traits and rotation-age objective traits and objective trait economic weights.

Windthrow damage in Picea abies is associated with physical and chemical stem wood properties

On 26 December 1999, the windstorm “Lothar” hit large parts of western and central Europe. In Switzerland, windthrow losses reached 12.7 Mio m3 of timber, corresponding to 2.8 times the annual national timber harvest. Although these exceptional losses were due to extreme peak velocities, recent changes in tree nutrition may have increased forest susceptibility. Previous controlled environment experiments revealed that wood density (associated with wood stiffness) tends to increase in elevated CO2, and to decrease when N-availability is enhanced (e.g., by soluble N-deposition). Such changes in wood quality could theoretically influence the risk of wind damage. We used the “Lothar” windstorm as a “natural experiment” to explore links between damage and wood properties. In 104 windthrow sites across the Swiss Plateau, more than 1,600 wood cores from (1) broken, (2) uprooted and (3) still standing (not damaged) spruce trees (Picea abies) were collected in February and March 2000. Wood properties, treering width and chemistry of the wood samples were analysed. Broken trees showed wider treerings in the decade 1990–99 compared to non-broken trees (either uprooted or undamaged trees). Broken trees also showed lower non-structural carbohydrate (NSC) concentration in sapwood, reflecting active structural carbohydrate sinks associated with fast growth. There was also a trend for higher tissue N-concentrations in broken trees. No significant differences between damage types were found in wood density and wood shrinkage during desiccation. We conclude that stem breakage risk of P. abies is associated with a stimulation of growth in the past decade and with changes in tree nutritional status. However, the risk for windthrow of whole spruce trees (uprooted but not broken) was not related to the studied wood parameters.

Tinjauan Hasil-hasil Penelitian Faktor-faktor Alam yang Mempengaruhi Sifat Fisik dan Mekanik Kayu Indonesia Review of Researches on Natural Factors Affecting the Physical and Mechanical Properties of Indonesian Wood

This review deals with several topics concerning natural factors affecting physical and mechanical properties of wood, i.e. (1) wood species; (2) age and location of growing; (3) position of wood sample in the stem; (4) diameter; (5) humidity, moisture content, and temperature ; (5) weathering and fungi ; (6) forest fired; that have been done by researchers who are members of Indonesian Wood Research Society. The purposes of this review are (1) to evaluate the research results that have been done, (2) to promote the applicable and feasible utilization of research results to the users, (3) to provide information concerning previous researches that might be useful for further researches. More than 60 wood species have been reported in this review. Besides the major and minor commercial wood species; lesser known species, i.e. Balsa ( Ochroma spp .), Randu ( Ceiba pentandra Gaertn.), Merkubung ( Macaranga sp .), Cengkeh ( Eugenia aromatica L.), Afrika ( Maesopsis eminii ), Kisereh ( Cinnamomum porrectum (Roxb) Kosterm), Kibawang ( Melia excelsa Jack.), Pulai Konggo ( Alstonia kongoensis Engl.), Sengon Buto ( Enterolobium cyclocarpum Griserb.), Salamander ( Grevillea robusta A.Cunn.), Kilemo ( Litsea cubeba Pers.), Tahongai ( Kleinhovia hospita Linn.), Sukun ( Arthocarpus altilis ), Arang ( Diospyros borneensis ), Berumbung ( Adina minutifolia ), Tisuk/Waru ( Hibiscus macrophyllus ), Urograndis ( Eucalyptus urograndis ), Kelapa ( Cocos nucifera L.), Kelapa Sawit ( Eleais guineensiis Jacq.), Laban ( Vitex Pubescens Vahl.), Rambai ( Baccaurea motleyana Muell.), Ki Sampang ( Evodia latifolia DC.), Nangka ( Artocarpus integra Merr.), Kalapi ( Kalappia celebica ), Gofasa ( Vitex coffasus ), Ketileng ( Vitex glabrata ), Cemara ( Gymnostoma sp .), and Lamtoro ( Leucaena glauca (Willd) Benth). have also been observed. The researches were generally done in relation to the utilization prospect of lesser known species, crops estate species, fast growing species, timber estate species, rural forest species, commercial species, for contruction/structural materials, handy-craft, musical instruments, or out-door exposures. Wood properties were interaction between specific gravity or density, moisture content, shrinkage and mechanical properties of wood. However, the values of those physical and mechanical properties in the papers could not directly compared to each other, because there were various testing standard and strength classification used. And unfortunately, researches on acoustic, thermal, electrical, creep, relaxation, and fatigue behaviour of Indonesian wood species were very rare or almost none.