It is necessary to know the nutritional characteristics of forest trees when considering the effects of changes in nutrient environment due to air pollution on forests. The reasons why Pinus densiflora grows on a poor nutrition area like ridge were examined. It is considered that the soil is acidic and the main nitrogen source is ammonium nitrogen in locations where P. densiflora grows. P. densiflora seedlings grown by both hydroponics and soil cultivation grow better when the nitrogen source supplied is ammonium nitrogen. Nitrate nitrogen is barely detectable in the roots, needles, and xylem saps in P. densiflora. Free amino acids detected in these seedlings are mainly glutamine and arginine, and nitrogen is transferred from the root to the shoot in the form of glutamine most. Absorbed inorganic nitrogen appears to be rapidly assimilated into amino acids in relation with root respiration. In the needles of P. densiflora grown in the field, the concentrations of bases, such as calcium and magnesium, are lower than the concentrations in most other coniferous and broadleaf trees. In many plants such as Cryptomeria japonica, bases are thought to be necessary for electrical balance when nitrate nitrogen is absorbed. However, P. densiflora does not use such a mechanism. In case of P. densiflora, ammonium nitrogen is the main nitrogen source; on the other hand, nitrate nitrogen is reduced immediately after absorption. Furthermore amino acid synthesis progresses smoothly in the root. The quick reduction of nitrate nitrogen in P. densiflora tree might be the adaptation to acidic soil areas where bases are lacking.

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To census the present butterfly fauna of Rinshinomori Park, Tokyo (the site of the National Forestry Research Center), I conducted field surveys on 203 days from 2010 through 2019 and recorded 40 species: 8 papilionid, 5 pierid, 9 lycaenid, 15 nymphalid, and 3 hesperiid species. By Tanaka’s criterion (Tanaka 1988), they comprise 25 forest species (62.5%) and 15 grassland species (37.5%). The Sunose environmental index was 74 that indicates a “moderate natural environment”. On the geographical distribution of the recorded species, the percentage of Himalayan-type (15.0%) species was higher and those of Siberian-type (15.0%) and Ussuri-type (5.0%) species were lower than the national averages in Japan. Percentages of forest, univoltine, egg diapause (overwintering) and Chinese-type species such as Antigius attilia and Japonica saepestriata have declined in comparison with the data collected in the park in 1970s by the National Forestry Research Center.

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Recently, the Forest Tree Breeding Center has been promoting the installation of labels with QR codes to construct a material management system that incorporates automatic identification and data capture. In this study, we used various materials to create labels with a QR code, and we compared the durability of the different labels over 3 years. For both adult tree and seedling labels, we found that a P-touch label coated with a polyethylene terephthalate film after printing with a thermal transfer printer exhibited high durability. However, because this label requires separate preparation of the printing paper and the label mount, it is relatively expensive. Moreover, although some of the labels that we examined were sufficiently durable for use in seedlings, further study is needed to develop a label for adult trees that may be used for more than 30 years.

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An assessment was made of the attitude calculation accuracy of hydraulic excavators used for the computerized construction of forest work roads. An inertial measurement unit (IMU) was mounted on the four parts (upper revolving structure, boom, arm, and bucket) that determine the posture of the excavator. The toe position of the bucket was calculated from the various posture angles, and the accuracy was verified using TS. The results revealed an average height error of 1.03 cm, which is compliant with the specified standard of a maximum error of 5.0 cm set by the Ministry of Land, Infrastructure, Transport, and Tourism. However, the error in the three-dimensional direction was as large as 7.05 cm. A close examination of the cause of this error revealed an error in the IMU azimuth measurement of 0.7° on average and as large as 6.0°. As a different way, the azimuth angle was calculated using the coordinate values of the rear prism surveyed by TS, and it was found that doing so reduced the average error in the three-dimensional direction to 1.75 cm.

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We found original copies of valuable forest ecological survey reports that were carried out in the early Showa era in Japan. The 662 survey reports discovered were the result of vegetation surveys conducted by technical officers in six regional forest offices (Aomori, Akita, Tokyo, Osaka, Kochi, and Kumamoto) and were based on the “Research Methods for Government-Owned Natural Forest,” issued by the Forestry Department, Ministry of Agriculture and Forestry in 1926. The reports contain abundant valuable original forest vegetation data, including tree size and vegetation maps. The purpose of this paper is to document the historical storage process of these reports, publish the report catalogue for forestry researchers, and digitize the original data to promote its use in future forestry research and management.

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