The production rate and labor productivity of grapple saw processing operations ₃ in a secondary hardwood forest dominated₃ by Quercus serrata was determined. The production rate was 3.2 m per hour and labor productivity was 1.6 m per hour per person, with one grapple saw operator and one chainsaw operator. The actual time required for processing was highly correlated with tree trunk diameter at breast height, demonstrated by our regression analyses of this association. Assuming 0.6 dry t/m ³ , the production rate demonstrated in this study is lower than that of overseas grapple saw hardwood processing operations, as the production rate in some cases is higher than that in this study despite the small volume per tree. Comparison between grapple and chainsaw processing operations in Japan indicated the possibility of an improved production rate with a grapple saw, despite the difference in tree size. On the other hand, the labor productivity of this study was relatively lower than production rate, because all the comparison cases were one-person operations. Therefore, grapple saw processing should prioritize one-person operations to improve labor productivity and reduce chainsaw use. However, as eliminating high-quality chainsaw processing would likely reduce the production yield percentage, the most efficient method for effective local resource use must be selected.

From April 2000 to January 2005, we monitored the chemistry of rainfall, throughfall, stemflow, O layer leachate, soil-percolating water, seepage water, and stream water in the Yamashiro Experimental Forest (YMS) in southern Kyoto Prefecture, Japan. To clarify the characteristics of YMS water quality, comparison was made with the data in the Forest Atmospheric Deposition and Stream Chemistry Database (FASC-DB) of the Forestry and Forest Products Research Institute (FFPRI). Rainfall acidity, and inorganic nitrogen and non-sea salt sulfate levels in precipitation were the same in the YMS as those at monitoring sites nationwide. However, throughfall and stemflow had a higher pH and percentage of K⁺ in total cations at the YMS compared to other monitoring sites. Seasonal variations in pH and K⁺ concentration were observed in the throughfall; both were high during the foliated period and low during the defoliated period. The O layer leachate was acidic and had high concentrations of dissolved organic carbon (DOC), Ca ²⁺ , and NO ₃ . Their concentrations were also high in the soil-percolating waters, and no decrease in DOC concentration with depth was observed. Compared to the other monitoring sites in the FFPRI, the stream water in the YMS had slightly higher electrical conductivity, and higher concentrations of NO₃ ^- and other ions. We speculate that the dissolved constituents are concentrated by evapotranspiration in the YMS watershed due to its warm, low precipitation climate. The high NO₃ ^- concentration may be related to the large supply of nitrogen compounds from the densely populated areas in the Kyoto–Osaka area, in addition to the supply of nitrogen from dead trees in the watershed.

The widths of tree growth rings of the main stems of 12 Betula platyphylla var. japonica individuals that were naturally regenerated in a birch stand at the Hokkaido Research Center were measured and converted to a machine readable data format. The sampled stems should have grown over 14 growing seasons. The individuals were felled in May 2019, and disks were sampled at 1-m intervals from a height of 0.3 m above the ground. The ring widths for every year were measured in four directions for each disk using a ring-measuring instrument. The number of cases where year-to-year change patterns in the ring widths were the same among the four examined directions was more than expected under the random condition. Finally, the data were assembled and saved as a comma-separated values file containing values for the mean radius of each stem, year, and height. In addition, stem analysis diagrams were drawn for each sampled stem.

Tree-ring analysis was performed for eight Cinnamomum camphora trees dead and fell after a typhoon storm surge at Ozato Matsubara coastal forest, Tokushima Prefecture, western Japan, to analyze the long-term growth process of broad-leaved trees planted in coastal forests. Tree-ring width in all four directions of the compass was determined on disk samples at 0.3 m ground height. Tree rings of 31 to 37 years were counted, and the mean tree ring width of each individual ranged from 5.5 ± 2.6 mm to 12.0 ± 4.6 mm with an overall mean of 9.4 ± 4.1 mm (±sd). The diameter at breast height was determined to reach 47.3 ± 9.6 cm within 30 years of the establishment, by using the ratio of diameters at 0.3 m and breast height. The sparse planting interval of 5.2 m to the nearest neighbor was causally associated with the quick thickening growth of the C. camphora trees.

We provide observational results of precipitation and runoff from 2011 to 2015 in the Tatsunokuchi-yama Experimental Watershed (34°42′N, 133°58′E) of the Kansai Research Center of the Forestry and Forest Products Research Institute. The experimental site belongs to the Seto Inland Sea Climate, and consists of a pair of adjacent watersheds, the Minami-dani and Kita-dani watersheds. Most of the area of the experimental site is underlain by Paleozoic sedimentary rocks, except the lowest downstream area and the right bank slope of Kita-dani, which is underlain by igneous rocks, mainly consisting of quartz-porphyry. The average annual precipitation from 1981 to 2010, which was 1181.2 mm, was taken as the normal value. The normal annual runoff summed with the normal monthly runoff was 355.1 mm in Minami-dani and 353.8 mm in Kita-dani. During the reporting period, the distribution of vegetation was the same as in 2010, but the growth of trees planted in 2006 on the left bank of the middle stream of Minami-dani was notable. Annual precipitation fluctuated biyearly around the normal value, with values greater than 250 mm and a mean value of 1355.8 mm. Typhoon No. 12 (TALAS) and No. 15 (ROKE) in 2011, and a seasonal rain front and Typhoon No. 17 (TORAJI) in 2013 caused high levels of precipitation. Dredging of the gauging weirs was performed at Kita-dani in late February 2013 and at Minami-dani in mid-February 2014. Runoff during dredging is shown as estimated values. The mean runoff values and runoff rates were estimated to be 395.7 mm and 29.2%, respectively, in Minami-dani, and 499.9 mm and 36.9%, respectively, in Kita-dani.