In accordance with the “Japanese Agricultural Standard for Cross Laminated Timber,” the bending Young’s modulus of laminae and the bending strength of finger-jointed laminae are graded by a bending test in a flat-wise direction. When a Cross Laminated Timber (CLT) was loaded in an out-of-plane direction, laminae in the CLT are loaded in a flat-wise direction and this direction matches with the direction of the bending test for the laminae. In contrast, when a CLT was loaded in an in-plane direction, laminae in the CLT are loaded in an edge-wise direction and this direction does not match with the direction of the bending test for the laminae. This study assessed the improvement in the accuracy of in-plane bending strength of CLT and compared the bending strength in flat- and edge-wise directions. The results showed that the average of Young’s modulus of sugi finger-jointed laminae in the edge-wise direction was 7% higher than that in the flat-wise direction, while the average of the bending strength of sugi finger-jointed laminae in the flat-wise direction was 20% higher than that in the edge-wise direction. Using bending Young’s modulus and bending strength of laminae in the flat-wise direction, an equation for bending Young’s modulus and bending strength of CLTs was derived and verified. Consequently, the estimated value of bending Young’s modulus and bending strength was well fitted with that of the measured value, and this estimation was also validated.

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To restore coastal forests heavily damaged by the tsunami following the Great East Japan Earthquake of March 2011, the Forestry Agency of Japan has been building berms along the coast in the damaged areas. These berms use sand (loamy sand) brought from adjacent hill areas as a growth base in which the seedlings of domestic tree species are planted. However, in these growth bases, soil surfaces are often covered with water because bulldozing and other heavy machinery has caused compaction of the soil, leaving it susceptible to submersion. The submersion of soils in water is problematic because of the potential for these conditions to interfere with the restoration of coastal forests. The aims of this research are to elucidate the cause of water stagnation in berms, and to evaluate the efficacy of countermeasures to combat water stagnation in these soils. Soils in berms at reforestation areas in Sendai are generally quite hard and dense, having no (massive) structure where the entire soil horizon appears cemented and very low water permeability. Some profiles have gley horizons in topsoil, caused by the reduction of Fe³⁺ under anaerobic conditions. We compared the effects of countermeasures on berms in these areas among the several types of tillage carried out using following machinery; the backhoe with a skelton-bucket, ripper-dozer, and plow/subsoiler. Soil hardness on berms decreased in all cases, although the passage times after execution of tillage were different (1- to 20-months). These findings indicate that the tillage for berms as a growth base were quite effective countermeasure at the depth of cultivated-soils and that the effects of them were kept up for at least 20-months.

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In the 1920’s, nine Japanese Double Gardenia, Gardenia jasminoides form. ovalifolia, trees were discovered at Tatsuda-yama in Kumamato Prefecture. In 1929, a section of the species habitat was designated a Japanese Natural Monument, the ‘Natural Habitat of Tatsuda-yama Yae-kuchinashi (Double Gardenia)’. However, after World War II, Double Gardenia was considered to have become extinct due to cutting and illegal collecting. Subsequently, in 1969, one Double Gardenia was found in the Monument area, part of the experimental forest of the Kyushu Research Center, Forestry and Forest Products Research Institute, but it disappeared within a few years. However, three Double Gardenia clones, “Asai”, “Nishioka”, and “Haishou-in”, derived from the original population were conserved. With the goal being to conserve genetic resources of the Double Gardenia, this report assesses the current status and distribution of the three clones by field surveys, consultation with experts and the literature, while morphological characteristics of the three Double Gardenia clones are also examined. Several distributions were confirmed with most having likely been planted around Mt. Tatsuda-yama. The “Haishou-in” was found to differ from the other two morphologically similar clones in terms of petal characteristics and flowering period. Further research will use genetic analysis to search for individuals that may be remnants of the original natural population and to clarify the relationships between each clone which will inform their conservation management into the future.

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