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Nakajima H.,Forestry Research Institute | Kodani J.,Ishikawa Agricultural and Forestry Research Center
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2013

A method for predicting beech seeding based on fallen male inflorescence number was evaluated in Hokuriku district, Japan. Flowering and seeding was investigated for 7-13 years at five stands in disjunct populations and nine stands in continuously distributed populations. It was demonstrated that female flower production can be estimated from fallen male inflorescence number from May to June. Also, it was possible to predict the proportion of filled seeds using estimates of female flower production in the current and previous year. However, Hokuriku district differed from Hokkaido and Tohoku districts in the minimum value of female flower production for mast seeding. In the disjunct populations, the proportions of empty and immature seeds were high, as a result of pollen limitation owing to reduced population size and/or low genetic diversity. Therefore, it is suggested that an equation for estimating the proportion of filled seeds should be formulated for each area and in each population classified by continuity of distribution. The effectiveness of the prediction method was verified by the approximate correspondence between the crops estimated from fallen male inflorescence number and the actual crops. This method is suitable for predicting seed crops until early summer and, for example, may be useful for assessing whether seeds can be collected in autumn. Source


Kodani J.,Ishikawa Agricultural and Forestry Research Center
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2013

To estimate the acorn crops as the food resource of Japanese black bear (Ursus thibetanus), I examined the relationship between the production of sound (mature) acorns and the number of fallen male inflorescences of three Fagaceae species (F. crenata, Q. crispula, and Q. serrata). The annual fluctuation of male inflorescences in F. crenata tended to synchronize strongly with that of the total or sound acorns, and the regression equation between the number of male inflorescences and sound acorns showed a high coefficient of determination. On the other hand, the annual fluctuation of male inflorescences and mature acorns in two Q. species did not synchronize as strongly as that in F. crenata, and the regression equation between the number of male inflorescences and mature acorns in both species showed a low coefficient of determination. However, the acorn crop size estimated by the predicted number of sound (mature) acorn substantially matched up to the results based on the monitoring survey of fruiting intensity of three species in each year. These results showed that grasping the number of fallen male inflorescences is effective to provide a rough tendency of acorn crops in three Fagaceae species in early summer. Source


Kubojima Y.,Japan Forestry and Forest Products Research Institute | Kobayashi I.,Japan Forestry and Forest Products Research Institute | Yoshida T.,Nagano Prefecture Forestry Research Center | Matsumoto H.,Ishikawa Agricultural and Forestry Research Center | And 2 more authors.
European Journal of Wood and Wood Products | Year: 2013

The object of this study is to investigate when wood begins to twist and the extent of the twisting force during drying. Japanese larch (Larix leptolepis Gord.) and hiba (Thujopsis dolabrata Sieb. et Zucc. var. hondae Makino) which tend to twist significantly when drying, were used in experiments to obtain multiple examples of grain angle (GA) variation in the R-direction. A measuring system to measure the twisting force during the drying of wood in real time was developed. It is thought that the time when twisting of timber by drying starts is subject to the variation in R-direction of GA; timber begins to twist when the portion with large GA begins to dry. There is concern that timber with large GA in the inner portion may become twisted during storage after kiln drying. The twisting stress measured in this study is effective for examining the load on the timber to control the twisting. © 2013 Springer-Verlag Berlin Heidelberg. Source


Nogami T.,Hakusan Nature Conservation Center | Yoshimoto A.,Hakusan Nature Conservation Center | Kodani J.,Ishikawa Agricultural and Forestry Research Center | Nozaki E.,Ishikawa Prefecture
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2013

For the purpose of predicting the infest of the Asiatic black bear, Ishikawa Prefectural Government conducted the survey for the prospective yield of the masts of the three Fagaceae species. The survey has been entrusted to the Ishikawa Nature Guide Association, which is a volunteers association for guide service of nature. As a result of questionnaire, most of the members who participated in the investigation answered that they were able to get a greater understanding about the relation between beechnut production and bear infest. And it became clear that this experience was also helpful to improve their normal activities of nature interpretation. Thus, to involve nature guides in such investigation activities is considered to contribute to promote the proper knowledge of bear infest issue to the public secondarily. In addition, when it entrusts a volunteer group, it is important to adopt not only the technical methods to conduct easily the investigation and open the workshop for investigations, but also to choose the investigation sites with an expert. Source


Mizutani M.,Fukui Nature Conservation Center | Nakajima H.,Forestry Research Institute | Kodani J.,Ishikawa Agricultural and Forestry Research Center | Nogami T.,Hakusan Nature Conservation Center | And 2 more authors.
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2013

The relationship between the acorn crops of trees belonging to the Fagaceae family and the mass intrusion of Asiatic black bears (Ursus thibetanus) into the residential areas of the Hokuriku region were investigated based on an acorn crop monitoring survey conducted over a 7-year period, from 2005 to 2011, in the Toyama, Ishikawa, and Fukui Prefectures of Japan. Large fluctuations were observed in the annual acorn production of both Fagus crenata and Quercus crispula located in the high-altitude areas of all three prefectures. In particular, extremely poor yields of acorns were noted for 2006 and 2010, which coincided with the mass intrusion of bears into the residential areas. In contrast, little fluctuation was observed in the annual acorn production of Q. serrata distributed in low-altitude areas, and there were no incidents of years with extremely poor yields. These results infer that food shortages, due to simultaneous poor crops of F. crenata and Q. crispula in the mountainous areas of Hokuriku region, triggered the mass intrusions of bears into residential areas. Since the fluctuations in the annual acorn production of these key species were synchronized across a wide geographic area, a comparative analysis and coordinated survey of the acorn crop monitoring of each neighboring prefecture should result in an effective as well as accurate forecast of the acorn yields and therefore of bear intrusions. Source

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