Mass mortality caused by bark beetles occurred locally in a subalpine fir (Abies mariesii) forest in the Zao mountain area in northern Japan. We examined the distribution of the mass mortality of A. mariesii trees and the corresponding locations to analyze the mortality rate in each section of a 50 m mesh, using satellite images and GIS, in a 528 ha fir forest in Yamagata Prefecture. Our results show that there were three areas where sections with mortality rates of 60％ or more were concentrated in this study area. They were located on western slopes with high altitude. However, since there were still many sections with low mortality rates in these locations, the local occurrence of mass mortality could not be explained by location alone. Sasa bamboo (Sasa kurilensis) dominates the forest floor in many fir forests. Study plots with higher sasa coverage had fewer juvenile A. mariesii trees. Sasa coverage tended to increase as altitude increased, and there were no A. mariesii seedlings and saplings in the plots at high altitudes. This tendency was extremely noticeable on the western slope of Mt. Jizoudake, which was also the area in which sections with high mortality rates were most concentrated in this study area. Therefore, mass mortality forests dominated by sasa at high elevations are predicted to be difficult to regenerate because they have few juvenile trees on the forest floor.

Copper-catalyzed carboazidation of alkenes with trimethylsilyl azide and cyclic ethers has been achieved. The employment of naturally abundant copper catalysts allowed cyclic ethers to be used as alkylating reagents under oxidative conditions. The use of styrene derivatives and 1,1-diaryl alkenes afforded carboazidation products. In addition, application of five-and six-membered cyclic ethers to the present reaction gave target organic molecules bearing azide and cyclic ether groups with perfect regioselectivity. Radical trapping and clock experiments revealed that the present reaction proceeded via the radical pathway. To further demonstrate the utility of this carboazidation reaction, transformations from the azide group to the related nitrogen-containing compounds were also performed.

Do Non-dormant Seeds of Black Locust Robinia pseudoacacia L. Contribute to their Natural Regeneration in? J Jpn For Soc 94: 261 268 Dispersal and germination traits were investigated for non-dormant seeds of black locust Robinia pseudoacacia L. by laboratory and field experiments. The dispersal period was ranged from early September to mid December and among this period, the non-dormant seeds accounted for overall half of the healthy seeds. In the laboratory experiment, non-dormant seeds could germinate at 15℃ or more. Though the substantial number of seedlings emerged from the non-dormant seeds in the field condition, the emergence was divided in two seasons i.e. the current autumn and next spring. The seeds sown in September October emerged in current autumn, whereas those sown later emerged in the following spring. Since soil temperatures were less than 15℃ after November, non-dormant seeds could not germinate but keep alive under the snow during winter. Eventually, 4.3 7.1％ of non-dormant seeds could survive by the end of next growing season, and several of them reached up to more than 1 m tall or more. Most of these large seedlings developed horizontal roots. These results suggest that the non-dormant seeds which arrived at an open site may germinate immediately, and subsequently developed root sucker, which enable them to form a new stand quickly after disturbance such as flooding events at the river basin.