Various strength tests of kouyouzan (Chinese fir: Cunninghamia lanceolata) obtained from multiple sites were conducted. The test results were used to evaluate strength property and verify the relationship with the current design strength. From the verification, the following conclusions were drawn. First, for mechanical grading of structural lumber under the Japanese Agricultural Standard for sawn lumber (JAS1083), it is appropriate to include the Chinese fir in akamatsu (Japanese red pine: Pinus densiflora) and other species groups for bending and compression. However, the shear should be equivalent to that of sugi (Japanese cedar: Cryptomeria japonica). Second, although only from the viewpoint of the select structural grade of A class structural lumber, for the Japanese Agricultural Standard for structural lumber and fingerjointed structural lumber for wood frame construction (JAS0600), it is appropriate to include JSIII for bending and compression and JSII for shear. Therefore, the current species groups are not applicable. For partial compression perpendicular to grain, all kinds of design strength are the same and will be equivalent to sugi. However, these results were obtained from a limited number of specimens, and neither JAS1083 was examined as visual grading of structural lumber nor JAS0600 was examined as no.2 grade for A class structural lumber. Additionally, for the shear strength and partial compression strength perpendicular to grain, some lumber had lower strength than the design strength of sugi. Moreover, some specimens with low density exhibited lower performance than sugi in terms of one-sided shear at nailed joints. As mentioned above, many issues remain, and data accumulation for further verification is essential.

The flagging method was conducted for tick survey in the Forestry and Forest Products Research Institute (FFPRI) in Tsukuba, Japan in May and June of 2022. Haemaphysalis flava, H. longicornis, Ixodes turdus, and Amblyomma testudinarium were collected. The wildlife host fauna in the area lacks large-sized animals such as sika deer and wild boar. Haemaphysalis flava, H. longicornis, and I. turdus may have been carried by infesting small and medium-sized wildlife and wild birds. However, A. testudinarium is commonly distributed in areas distributed by wild boars. Furthermore, cases of tick-bite in human are frequently caused by A. testudinarium. The staff who moved back from the fieldwork and the small and medium-sized wildlife which frequently visit the FFPRI from the wild boar distributed areas are necessary to be considered as the possible cause of A. testudinarium introduction.

Differences in the accuracy of cone detection on the tree crown of Abies sachalinensis were compared using multiple models of the object detection algorithm “You Only Look Once” (YOLO). Training and validation were conducted using YOLOv4 and YOLOv5m, which both showed an average precision (AP) of around 0.9. Five models of YOLOv5 (YOLOv5n, YOLOv5s, YOLOv5m, YOLOv5l, and YOLOv5x) with different neural network layer sizes were also compared. AP was 0.9 in all models except for YOLOv5n, and the accuracy was similar regardless of the neural network layer size.

The Kamabuchi Experimental Watershed (KEW) is located in the snowy cold region of Mamurogawa Town, Mogami-gun, Yamagata prefecture, and has been observing since 1939 to clarify the water resource storage function of forests. The current KEW is covered with a mixed forest of coniferous and broadleaf trees such Cryptomeria japonica, Chamaecyparis obtuse, Fagus crenata and Quercus serrata. In this report, an overview of the topography, vegetation and forest operation history of the Nos. 1, 2 and 3 watersheds of the KEW are shown, and the maintenance works of the forest-watershed experiment are introduced. In addition, this report shows daily runoff at each watershed, and daily precipitation and snow depth at Yamagata Experimental Forest adjacent to the KEW from January on 2006 through December on 2010.

The Kamabuchi Experimental Watershed is located in Mamurogawa Town, Mogami-gun, Yamagata prefecture (38°56′12″ N, 140°15′58″ E), and the four small watersheds from No. 1 to 4 were established. Observations of precipitation has been conducted since 1938. Runoff have been conducted at No. 1 and 2 since 1939, and at No. 3 and 4 since 1961. This report builds upon earlier reports by describing daily precipitation and runoff observed at No. 1–4 from January in 2011 through December in 2016.

Since 1999, we have conducted meteorological observations in a deciduous broadleaf forest in Sapporo, Japan. In this article, we present observation results for a 20-year period between 1999 and 2018. The observation was halted between September, 2004 and May 2005, and again from September, 2018 onward due to typhoon damage to the facilities. The mean global radiation, air temperature, and vapor pressure were 12.6 MJ m⁻² d⁻¹ , 7.4°C, and 9.4 hPa, respectively. The maximum frequency of wind direction was south–southwest, with a mean wind velocity was 2.8 m s⁻¹ . The mean annual precipitation from 2007 to 2018 was1246 mm.

The original document of forest survey in the Ogasawara Islands (the Bonin and Volcano Islands) was digitized as a part of data archive of the research reports from government-owned natural forests in the early Showa era. We scanned images of the original document from the forest vegetation survey report written in classical Japanese and translated it to current Japanese. Moreover, we demonstrated plants with their current names corresponding to their names at that time. This document summarizes the field surveys conducted in 1935 in the national forests at the Ogasawara Islands. In this document, the composition and structure of various forest communities that covered the entire islands at that time, and the distribution of principal component plant species were described. Moreover, vegetational continuum in the islands was discussed. It provides useful information about the forest restoration projects in the Ogasawara Islands; it is a valuable academic asset that demonstrates forest officers’ insights into nature and research capabilities of forest vegetation.