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To preliminary evaluate the potential wood utilization of Sukaczev trees naturally regenerated in Mongolia, growth characteristics (stem diameter and tree height), wood properties (annual ring width, basic density, and compressive strength parallel to grain at the green condition) of core samples, and stress-wave velocity in stems were investigated for trees grown naturally in three different sites in Selenge, Mongolia. trees, naturally grown in Nikko, Japan, were also examined to compare wood properties between the two regions. The mean values of stem diameter, tree height, stress-wave velocity of stems, annual ring width, basic density, and compressive strength parallel to grain at green condition in Mongolian were 17.6 cm, 14.1 m, 3.50 km s, 1.27 mm, 0.51 g cm, and 20.4 MPa, respectively. Basic density and compressive strength were decreased first from the pith, and then gradually increased toward the bark. The wood properties of trees grown naturally in Mongolia were similar to those in trees grown in Japan. Growth characteristics, especially stem diameter, were positively correlated with the stress-wave velocity of stems and basic density. Early evaluation of basic density in trees is possible by using wood located 2 cm from the pith. Basic density at the position from the 1st to the 15th annual ring from the pith showed significant between-site differences in Mongolian . Based on the results, it is concluded that the wood of trees grown in Mongolia may be used for industrial products as well as those from similar species in other countries.Betula platyphyllaBetula platyphyllaBetula platyphyllaB. platyphyllaâ1â3B. platyphyllaB. platyphyllaB. platyphyllaB. platyphyllaB. platyphylla

To clarify sawn-timber quality and those among-family variations of hinoki cypress (Chamaecyparis obtusa), modulus of elasticity (MOE) and modulus of rupture (MOR) were evaluated for 97 pieces of 38 by 89 mm sawn timber produced from half-sib families planted in a progeny test stand at Chiba, Japan. Correlations were evaluated on mechanical properties in standing trees and logs with MOE and MOR in the sawn timber. Elastic properties, such as dynamic Young's modulus of logs and MOE, were affected by genetic factors compared with air-dry density and MOR. The 5% tolerance limits at a 75% confidence level (f0.05) of MOE and MOR were 8.03 GPa and 39.4 MPa, respectively. The f0.05 values of MOR exceeded the characteristic value of the sawn timber in visual grading class SS of Japanese Agricultural Standard for the JS-I. Visual grading of the sawn timber was effective for eliminating timber with lower MOE. Stress-wave velocity and dynamic Young's modulus of log and timber were significantly correlated with MOE of sawn timber. Correlation coefficients were also significant between MOR of sawn timber and dynamic Young's modulus or MOE. [ABSTRACT FROM AUTHOR]

Decay process of wood of Japanese white birch [Betula platyphylla Sukaczev var. japonica (Miq.) H. Hara] tree by Inonotus obliquus (Fr.) Pilát was clarified by using the regression model in wood color and chemical components as a function of height position (1, 2, 3, and 4 m above the ground), wood type (sound wood and decayed wood), and their interactions, and anatomical observations. The 3 m height position, at which a sclerotium of I. obliquus was found, showed the highest decayed area percentage among four height positions. By the results of two-way analysis of variance, wood type affected all color indice. In addition, all factors (height position, wood type, and their interaction) were significant in all wood chemical components except for Klason lignin and hemicellulose. In the wood of the reaction zone, some substances were formed in the lumens of many vessels and a few wood fibers. Based on the results, we proposed the decay process of I. obliquus in naturally grown Japanese white birch, and the proposed process will contribute to a full understanding of the interactions between I. obliquus and Japanese white birch in the future. [ABSTRACT FROM AUTHOR]

Boundary between core and outer wood should be clarified for tropical fast-growing tree species to utilize its wood resources under sustainable forestry. This study aimed to determine the boundary between core and outer wood based on the mixed-effects models for radial variations of anatomical characteristics and wood properties in three fast-growing tree species grown in community forests in Indonesia – Acacia mangium Willd., Maesopsis eminii Engl., and Melia azedarach L.. On the basis of the results of the radial variation modeling, almost all anatomical characteristics and wood properties were shown to increase or decrease from pith to bark and then become almost stable. The boundary values between core and outer wood based on exponential function with plateau for absolute changing ratios of estimated properties were 6.1, 6.8, and 5.5 cm for A. mangium, M. eminii, and M. azedarach, respectively. In conclusion, boundary between core and outer wood in respect to multiple characteristics and properties in tropical fast-growing tree species can be determined by combination of mixed-effects modeling and exponential function with convergence. [ABSTRACT FROM AUTHOR]