Intrafamily variation of grain spirality was investigated in 210 individual trees of a control-pollinated family of hybrid larch (Larix gmelinii var. japonica × L. kaempferi) at age 12. Grain spirality at each growth ring boundary was measured by applying the splitting method to specimens obtained at around breast height from the sample trees. Mean and maximum spiralities were 0.96º ± 0.58º and 2.72º ± 0.78º (mean ± standard deviation), respectively.These results indicated that, among various larch populations, the investigated family had low-spirality and that intrafamily variation was large even among full sibs. The analysis of interrelationships among various parameters of grain spirality revealed a relatively high correlation between grain spirality at the outermost ring and mean spirality, indicating that log sorting for grain spirality can be achieved when outermost ring spirality can be measured on the logs. In conclusion, the combination of the genetic improvements obtained via family selection and log sorting to select better individual logs from each family is a promising approach towards a more efficient wood utilisation and sustainable forestry development.

The Ryuunohige sugi cultivar, which is grown in the Kumamoto and Oita prefectures in Kyushu Island, has a moderate rate of growth, straight stems and good resistance to the damage by the strong winds of typhoons.However, little is known of its wood properties. In this study, thirty trees were sampled from a forest stand in Kikuchi, Kumamoto prefecture, and logs and wood discs were cut from 0.6 to 8.0 m height, to evaluate the variation of the wood properties among and within the tree stems. It was found the wood has high density and stiffness, with a high percentage of latewood and low microfibril angle, compared with those properties reported for other sugi cultivars. The tangential and radial shrinkage of the wood was relatively high, compared with other sugi cultivars.The heartwood of the green logs had a low moisture content (except at the base of the stem), which reduces the energy required for kiln-drying, and the air-dry heartwood color had high lightness (L*), average redness (a*) and high yellowness (b*). There was low variation in wood properties among the trees, and similar within tree stem patterns for all the trees. The Ryuunohige cultivar has a favorable combination of wood properties, which together with its good stem form and resistance to wind damage, should make it desirable cultivar for plantation use in Japan.

Ogawa Forest Reserve is a 6-ha study plot established in the Ogawa Beech Protected Forest located in the northern region of Ibaraki Prefecture, assigned for researching long-term forest ecology. Approximately 60 tree species and abundant herbaceous grow in the forest floor of this plot. Although the flora list of vascular plants was previously organized according to the old taxonomic system, detailed identification and compilation, including herbaceous plants, have not yet been conducted. Thus, we worked on re-identification of the herbarium specimens collected and retained to date and arranged the flora list following the APG system during 2021-2022. Furthermore, we carried out field surveys in and around the plot and organized a comprehensive flora list of vascular plants. As a result, we recorded 358 species of vascular plants that belong to 88 families and 219 genera. Additionally, we discovered several previously unknown phytogeographically significant species in the field survey.

The double-flowered gardenia, Gardenia jasminoides forma ovalifolia, was first discovered in the 1920’s on Mt. Tatsuda-yama. Although considered extinct in its natural habitat, the double-flowered gardenia survives in cultivation with all individuals consisting of clones originating from wild individuals. The gardenia has been planted for ornamental, greening and conservation purposes in various sites. However, plantings of the double flowered gardenia have frequently been damaged by insect and mite pests. In this study, we conducted a literature review and field survey to investigate the gardenia pests with the aim of accumulating information that may be beneficial for its utilization in cultivation and the success of conservation-plantings for double-flowered gardenia. In the literature review, information on the insects and mites which damage the single-flowered form of gardenia, G. jasminoides, were summarized including the infection pattern of each pest species. The field survey was conducted to identify and record pests found on both forms planted in the Tatsuda-yama Experimental Forest of the Kyushu Research Center, Forestry and Forest Products Research Institute from mid-May to early December 2022. The literature review revealed that a total of 40 pest species, including 13 species of Lepidoptera (12 moth species and one butterfly species), twenty-two species of Hemiptera, four species of Thysanoptera, and one species of Acari have been reported as pests. During the field survey, a total of nine species were identified as pests: eight species of Lepidoptera and one species of Hemiptera. Three moth species (Somena pulverea, Ectropis excellens and Microleon sp.) found in the field survey were not recorded as pests in the literature. The field survey also demonstrated the importance of controlling three particular pests, Cephonodes hylas, Alucita flavofascia and Prophantis adusta, which did serious damage to both gardenia forms during our field survey.