Reliable forestry technology studies should be based on the scientific base and the social justice. It means that the technologies necessary for the sustainable forest management to maintain and enhance the multiple functions (services) of forest ecosystem should be studied. As the basic studies on forest management, it is essentially necessary to clarify the tendency how develop the stand structure after a main disturbance. And then, it is also necessary to clarify how the functions of forest ecosystem vary in accordance with stand development stages. By grasping this relationship, the target stand structure for each function can be settled on the desirable stage. It is always necessary to evaluate the technology systems by relating to total organized technology and individual technology such as thinning. In forestry (forest science), although basic studies have developed, applied studies have delayed. The reason of this was searched for and what is necessary to improve it was discussed. The most important thing for it is considered to the existence of forester such as the one seen in European countries. Such high revel leaders of technology should be essential for the development of forestry technology studies.

Ambrosia beetle traps were installed in the Suzuka Youth Forest Park, Mie Prefecture, from July to October, and the number of captures of oak ambrosia beetles Platypus quercivorus (Murayama) was investigated daily. From the results of the analysis of the relationship between the number of captures and climate conditions, it is conceivable that this beetle quickly flies to a new host tree after escaping from the previous tree. In addition, it was established that this beetle has difficulty flying not only on low-temperature days, but also on high-temperature days. Furthermore, the number of captures decreased in the period with longer daylight hours and lower precipitation (the end of July to the end of August), and the number of captures increased sharply on a day following a day with heavy rainfall. Therefore, it is thought that this beetle refrains from flying in the midsummer season during dry conditions and high temperatures, and that they actively fly in humid seasons such as the rainy season (mainly June) or periods of autumn rain (mainly September). It was also confirmed that this beetle tends to fly more readily on days with a gentle breeze than on windless days or on days with a strong wind. As a result of distinguishing between the Pacific Ocean type and the Sea of Japan type according to the number of circular holes on the female mycangia, it became clear that both types are mixed in this investigation area. Regarding the beetles captured in September, the relationship between the ratio of the Pacific Ocean type and climate conditions was analyzed. The results suggested that there was no major difference in climate conditions that made flight easier between both types. From the above, it can be considered that the behavior of P. quercivorus in the rainy season has become more active as the temperature of the rainy season has increased due to global warming, which may be one of the reasons for the increase in Japanese oak wilt disease.

Kumamoto Prefecture in Japan was struck by two huge earthquakes of Japanese seismic intensity scale 7 in April 2016. This paper describes the following sediment-related disasters caused by the 2016 Kumamoto Earthquake: a debris flow, a landslide and a collapse. We discuss debris flow runoff characteristics based on relationship between the torrent gradient and the sediment concentration and landslide and collapse occurrences based on slope stability analyses. Especially, we set both rainfall and earthquake calculation conditions for a semi-infinite slope and conducted slope stability analyses that focused on the outbreak factor of slope disasters. According to the results, when the debris flow structure consisted of a high sand-water mixture, the material of a small particle size raised the pore water density. An earthflow and a mudflow might form in the mild gradient torrent, arrive downstream and overflow even if the bed slope gradient is very small. For a landslide and a collapse, earthquakes caused a repeated load and generate excess pore water pressure, and since they reduced the shear strength near the sliding surface, the mountain slope lost stability and collapsed rapidly. If we could appropriately estimate the loss of the shear strength caused by the earthquake, we might be able to explain mass movement occurrences on a mountain slope that didn't collapse due to rainfall. Depending on the earthquake's scale, mass movements might not occur. Our result suggests that the enormity of the 2016 Kumamoto Earthquake was a primary factor in its destruction.