After the Great East Japan Earthquake in March 2011, countermeasures against earthquakes and tsunamis related to the Nankai Trough in southwestern Japan became an urgent issue, and Shizuoka Prefecture has been working on the construction of “the Fujinokuni Forest Seawall” since 2013. On the other hand, in the coastal area of Hamamatsu City, a coastal disaster prevention forest with a seawall function based on the CSG method has been developed, and was almost completed in March 2021. The growth of trees planted on the embankment of the seawall is affected by various factors, and this paper introduces a case study of coastal disaster prevention forest development, focusing on the wind environment around the seawall, selected tree species, and physical characteristics of the embankment. It was introduced that the wind blowing from the sea side around the seawall generates a circulating current when it blows over the top of the embankment and down to the land side, that the magnitude of the circulating current changes when the wind direction changes, that the growth of planted trees varies depending on the species, and that there are several patterns in the vertical distribution of the soil softness of the embankment. In the future, it is expected that new greening technology will be fostered to cope with the new conditions of creating coastal disaster prevention forests on tidal embankment.

We investigated the growth of cherry trees in the coastal pine forest near the Sendai Bay 10 years after the tsunami disaster. In the summer of 2020, for a total of 90 trees, we recorded tree vigor in the tree crowns and sprouting from 5 m below part of the trunks. Many of the trees showed progressive top-dieback of their crowns and an overall decline in vigor. Conversely, many of the trees showed sprouting from their lower trunk with a range of 1－103 sprouts and an average of 23.5 sprouts per trunk. Half (50.2%) of the sprouts were thin (2－4 mm in diameter), and there was no significant difference in the number of sprouts between species. Principal component analysis was performed based on the sprout position, and cluster analysis was performed with the principal component values, resulting in six clusters. Cerasus jamasakura was characterized by a relatively large number of trunks (36.7% of 71 trunks) belonging to the clusters with a higher number of sprouts in the upper parts of the trunk. The majority (71.4% of 14 trunks) of C. leveilleana belonged to the cluster with a small number of sprouts in all positions. In Padus grayana, 80.0% of 5 trunks belonged to the clusters with few or no sprouts in the upper parts. The cherry trees were able to avoid dying at the individual level by diverting their energy input toward new sprouts. These sprouts potentially contribute to the re-formation of the coastal forest in the future.

Eichhornia crassipes (Mart.) Solms.is listed as one of the worst invasive alien plants that can be introduced to the new environment primarily by human activities. They have very high reproduction rates in favorable conditions, especially concentrated nutrients. Native plants' habitats can be encroached by the density of Eichhornia crassipes mat and disappear in their environment. This study aims to study causes of the increase of Eichhornia crassipes by analyzing land use/land cover and water quality in Nong Bong Khai Non-hunting Area, Chiang Rai, Thailand. Then we used unmanned aerial vehicles (UAV) with 2 flight altitude levels (30m, 90m) for non-submerged aquatic vegetation mapping to study the distribution. The results showed that increases in Eichhornia crassipes resulted from high concentrations of nutrients in water. From 2009 to 2018, The land use/land cover reports indicated changes in land use type which area of field crop highly increased. The distribution map that was generated by applying a 90-m orthophoto from the UAV showed high covering area of Eichhornia crassipes by 13.82% of the lake area. Also, the vegetation map generated from a 30-m orthophoto showed the distribution and proportion of Eichhornia crassipes were more than those of other native plant species. This study showed that changes in land use/land cover around the lake affected water quality changes, which was a main cause of highly increasing rates of Eichhornia crassipes. Moreover, the orthophoto from the UAV at different altitude levels was suitable and useful for monitoring the distribution of Eichhornia crassipes and also other plant species.

In order to improve seed germination rate of Miscanthus sinensis Andersson, this study was conducted on seed weight or time of gathering. Seeds were divided into Heavy, Medium, or Light; dried at 5 ℃ or 25 ℃ in dark condition; watered at 25 ℃ in light condition for 12 hours. As a result, final germination rate was more than 70％ in both Heavy and Medium; was 20％ in Light. Seeds gathered from November to January were subjected to the same treatment. Final germination rate of seeds gathered in November was less than 10％; that in December after the treatment was more than 60％; that in January was more than 50％ regardless of the treatment. Percentage of seeds in Light was 95％ in November, but only about 30％ in December and January. Therefore, a better time of gathering seeds was after December, and removal of lighter seeds might improve germination rate.

This study aims at the implementation of a home gardening therapy program and its evaluation in terms of psychological effect. In this therapy people can avoid close contact with each other and use it even after Covid-19. Four kinds of home-based horticultural kits were sent every 3 weeks, one at a time. Participants themselves made the kits, joining the online meetings. The result of POMS2, an assessment analysis of mood, showed a significant improvement trend in all scores of the TMD (total mood state), fatigue-anhedonia, and friendliness items. This program has gained psychologically positive effect to some extent. With the internet, this home-based horticultural therapy can be provided anytime any place, even for those who have difficulty in going out or lived in remote areas.