Major Wood Species Research Articles

Economic Analysis of Sawnwood Marketing in Isokan Local Government area Osun State, Nigeria

Sawnwood is wood that has been produced either by sawing lengthways or by a profile-chipping process and is greater than 6 millimetres. The study evaluates the economic analysis of sawnwood marketing in Isokan Local Government area of Osun state Nigeria using appropriate standard methods. The results showed that 67.5% of the respondents were males while 28.3% were females. Most of the respondents (50%) are in their active ages, a large percentage (51.2%) of the respondents got into the business of planks marketing by training and started its runs through bank loans. Eight (8) major wood species: Albizia zygia, Blighia sapida, Ccordia milleni, Gmelina arborea, Milicia excelsa, Nuclea diderrichii, Termilania superba, and Triplochiton scleroxylon were sold in the study area. The constraints faced by the plank market business are unavailability means of transportation, government tariffs, price fluctuation in purchase, scarcity of timber and bad roads. There is significant relationship between the socio economic characteristics and the constraints facing sawnwood marketing in the study area. Results showed that for every $0.0022 invested into the sawn wood business, $0.0055 is returned, this implies that timber marketing business is a worthwhile business. It is thus recommended that there is a need for sawn wood marketers to organize themselves into cooperative groups in order to secure loan and credit facilities from funding agency so as to ease the constraints faced by them to boost their returns.

Unique characteristics of residual stress distribution of large-diameter keyaki (Zelkova serrata) logs and examination of their measurement method

Large-diameter keyaki (Zelkova serrata Makino) logs have long been used in Japan as high-quality material especially for traditional construction and furniture. However, unlike other major wood species in Japan, keyaki has been practically considered as a wood species of high difficulty when processing. Keyaki frequently shows processing defects due to sawing, such as warping, cracking, and so forth, which often reduces the production yield of logs. Furthermore, there are drastic differences in those behaviors between individual logs, so causing unexpected processing defects. A scientific approach is required to improve this situation, but data on the material characteristics of keyaki were scarce. This study aimed to characterize the radial pattern of the residual stress as one of the processing-related characteristics. The measurement method was also examined. This study used diametral planks obtained from large-diameter keyaki logs to measure released strain of residual stress from pith to the bark sides. The results showed the distribution of released strain often showed peculiar zig-zag patterns characterized with localized residual stress, unlike the smooth bell curve pattern seen in typical logs of other species. Because of the unique characteristics, some practical points related to the measuring methodology were investigated. The extent of influence of this residual stress in the longitudinal direction was limited to within 30 cm from the site of measurement of the strain. In addition, the length of log necessary to measure the released strain without being affected by crosscutting was more than four times the log diameter—greater than the diameter ratio theorized by previous studies.

Seasonal Signal of Photosynthesis in the Forests of North Eurasia

The seasonal course of the water potential in branch xylem reflects the dynamics of photosynthetic СО2/Н2О exchange in the forest stand. Long-term figures of water potential in the branches of major wood species growing in East Siberia—larch (Larixcajanderi Mayr), pine (Pinussylvestris L.) and birch (Betulaplatyphylla Sukaczev)—have been analyzed. The seasonal dynamics of the water potential showed its minimum in the first half of the vegetation period. The time when the minimum of water potential was observed concurred with the earlier determined peak in seasonal dynamics of net ecosystem exchange (NEE) of C/СО2 in the forests of East Siberia. Statistical analysis of a long-term time series of atmospheric СО2 concentration along the latitudinal zone (43°07′–55°45′ N) of the transcontinental transect from Moscow (55°45′ N, 37°34′ E) to Vladivostok (43°07′ N, 135°54′ E) corroborated the existence of the seasonal minimum of atmospheric СО2 in the first half of the vegetation period. However, this transcontinental Eurasian minimum of atmospheric СО2 was reached a month before such a minimum in the region of East Siberia (Yakutsk, 62°05′ N, 129°33′09″ E). It was concluded that the minimum of atmospheric СО2 concentration is a seasonal signal of photosynthesis in the regional forest ecosystems, and time shift of this signal might serve as an indicator of modification in the regional biogenic cycle of carbon caused by climate fluctuation.

Collapse and physical properties of native and pre-steamed Eucalyptus camaldulensis and Eucalyptus saligna wood from Tunisia

Eucalyptus is the second major wood species used for Tunisian reforestation since 1957, and they are found around the country in several arboretums. Eucalyptus may be an interesting raw material to the Tunisian wood industry. The main obstacle to its industrial exploitation is its natural propensity to incur internal checking, collapse and a high transverse shrinkage during industrial drying process. This study focused on the physical and mechanical properties of reforested Eucalytus saligna and Eucalyptus camaldulensis from the north west of Tunisia. Moisture content, densities, shrinkages and mechanical properties were determined. Then, the impact of pre-steaming on the physical properties of modified wood was investigated. The results showed that both Eucalyptus possess low dimensional stability and mechanical properties compared to other Eucalyptusspecies from Tunisia, Morocco, Australia and Brazil. These wood characteristics were mainly due to their low density and sensitivity to collapse reactions, occurred during drying. Pre-steaming process reduced Eucalyptswood moisture content, changing the wood permeability and resulting in a residual collapse recovery and a decrease in wood shrinkage. Pre-steaming treated E. camaldulensis and E. saligna wood could be valuable as furniture and/or structural material without being submitted to moisture content variation.

인도네시아산 주요 조림수종의 해부학적 특성 II

The anatomical characteristics of eight major wood species planted in Indonesia were investigated to provide val- uable information for their effective utilization. The growth-ring boundaries of Damar and Sumatran pine were indistinct. Resin canal was found in Sumatran pine but it was not observed in Damar. Cupressoid pit and taxodioid pit were found in Damar and window-like pit and pinoid pit were observed in Sumatran pine. Tracheid length of Damar and Sumatran pine was shorter than 3,000 µm. There were uniseriate rays in Damar and Sumatran pine and fusiform ray in Sumatran pine. All the hardwood species observed in this study were diffuse-porous. They had different vessel groups, i.e., solitary pore in Afrika and Simpur Batu, pore cluster in Angsana and mostly 2-4 rows of radial pore multiple

Investigation of the Effect of Organoclay Additives on Mechanical Properties of PF resin and MPB-OSL using Creep Behavior Analysis and IB Test

ABSTRACT The effect of organoclays on the mechanical properties of cured phenol formaldehyde resin and oriented strand lumber made from Mountain Pine Beetle killed pine strands was analyzed. Three organoclays were used: a natural montmorillonite, hydrophobic organically modified 10 A, and hydrophilic organically modi-fied 30 B. The oriented strand lumber samples were less creep deformation as well as improved internal bonding strength by adding organoclays in the order of 10 A 2% > MMT 2% > 30 B 2% > control. Furthermore, time-temperature superposition (TTS) analysis was proved to be able to predict the long-term creep behavior of MPB-OSL samples. Keywords : creep behavior, organoclay, internal bonding, MPB-killed pine, oriented strand lumber (OSL), time-temperature superposition (TTS) 1. INTRODUCTION Lodgepole pine (Pinus contorta) is a major wood species used to produce wood composites in Western Canada. However, approximately 4.2 million hectares of the total 8 million hec-tares of mature lodgepole pine in the central in-terior of British Columbia has been infested by the Mountain Pine Beetle (MPB, Dendroctonus ponderosae Hopkins) (Morford et al., 2004; Natural Resource Canada, 2004). To maximize the value from the pine forests, most forest product companies in the province have been harvesting green timber. This will inevitably re-sult in an enormous amount of MPB infested wood, potentially not suitable for traditional wood products. However, the large amount of MPB infested wood could be utilized for wood composite products, one possible end-use being oriented strand lumber (MPB-OSL) (Feng et al., 2007; Oudjehane et al., 2008∼2009).Recently, nano-fillers have been receiving significant attention due to their ability to im-prove mechanical properties and thermal stabil-ity of composite materials (Pinnavaia et al., 2000; Lei et al., 2006; Lin et al., 2005; Lei et al., 2007) Organoclay/polymer composites have exhibited dramatic increases in strength, barrier

양평 지평향교 대성전 목부재의 수종 및 연륜연대 분석

양평 지평향교 대성전의 목부재에 대한 수종 식별과 연륜연대 분석을 통해 정확한 수종과 건축역사를 조사하고자 하였다. 목부재 49점 가운데 연송인 잣나무류로 식별된 창방 5점과 장여 1점을 제외한 43점은 경송인 소나무류였다. 그리고 5개 목부재에 대한 연륜연대가 측정되었는데, 수피가 있는 대보 1점과 종보 1점의 마지막 연도가 각각 1718년과 1720년(만재 형성 완료)으로 측정되어 "학교등록"에 수차례 기록되었던 지평향교 대성전의 이건이 1720년대에 실행되었거나 이건 없이 대규모의 중수가 있었음을 유추할 수 있었다. The objective of this study is to conduct the species identification and tree-ring dating for the wood elements of Daesungjeon (main hall) in Jipyeong Hyanggyo, a Confucian shrine in Jije-myeon, Yangpyeong-gun, Gyeonggi-do, Korea. Major wood species for Daesung Hall was Pinus densiflora (88%) belonging to hard pine. The other species was P. koraiensis belonging to soft pine. One large beam and one collar beam with bark were dated to A.D. 1718 and 1720, suggesting either a large-scale repair or moving in 1720s as the record of an historical document 'Hakgyodeongrok'.