Thuja standishii (Gordon) Carr. (Cupressaceae) is an important endemic conifer of Japan but unlike other endemic Cupressaceae species there is a general lack of information about the species including its current distribution, ecology and conservation status. This study investigated the geographic range of the species and evaluated the number of recent population extinctions using available published and online resources along with field based investigations. Additionally, the species potential range was investigated using species distribution modelling. Thuja standishii was found to have a wide range in Japan from 40.67˚ N in northern Honshu to 33.49˚ N in Shikoku occurring across a variety of habitats from warm temperate evergreen forest to near the alpine zone. The core of its range is in central Japan including in both high and low snow-fall mountain regions. On the other hand, the species is extremely rare in western Japan being confirmed at only eight locations including five sites in Chugoku and three in Shikoku. These include the most extreme warm-edge populations known in the species that were poorly predicted by the whole range species distribution model. These populations are of great conservation significance and either represent long term persistence in refugia isolated from the species core range in central Honshu or remnants of a formerly more widespread occurrence in the warm temperate zone of western Japan lost over millennia to human activity. Overall, the species population trajectory appears to be stable with evidence for three population losses only that occurred in the mid-20th century.
Quantification of climatic damage to forests and its differences among regions and species is essential for forestry and forest conservation. Drought risk of forests is one of the critical subject in recent years under the global warming. Temporal, regional, and among-species variations in drought damage at private forests in Japan were investigated based on statistical data from 1959 to 2014, especially concentrating on recent 36 years for which original detail data were available. 1- to 5-years-old stands of private planted forests (PPF1-5) account for 95.3% of actual loss area, which was calculated as the damaged area multiplied by the ratio of the number of damaged trees to that of planted trees, caused by drought damage at whole private forests. The mean annual ratio of actual loss area caused by drought damage to total forested area (rd_real) of PPF1-5 over Japan was 0.26% and showed large inter-annual fluctuation without significant temporal trend. In variation among prefectures, the mean annual rd_real at PPF1-5 were relatively large in Hokuriku, Koushin, Kinki, and Chugoku regions (the south western part of the main island of Japan) and Kagawa prefecture, and were small in Tohoku, Kanto, and Tokai regions (the north eastern part of the main island of Japan) and Hokkaido and Kyushu islands. Annual rd_real of Chamaecyparis obtusa at PPF1-5 was larger and smaller than those of Cryptomeria japonica in 17 and 2 prefectures, respectively. Considerable amount of actual loss area was reported at mature stands in Kyushu in 1994, in which rainfall was quite small than usual from summer to early autumn. As the drought damage at mature stands, which should cause greater economic loss and ecological disturbance, occurred infrequently, comprehensive and long-term monitoring of forest damage needs to be continued to evaluate the trend of drought damage at mature stands.
Soil scarification is a natural regeneration practice that has been widely conducted during the late 1960s and 1990s as a low-cost birch reforestation technique on Hokkaido, the northernmost island of Japan. It has recently received renewed attention as a low-cost reforestation technique following a final cutting of fir plantation. Scarification practices inevitably bring soil disturbance, therefore sustainable forest management should be weighed against the loss of soil resources. To clarify the residual state of soil disturbance in scarified birch forest, we investigated the physicochemical properties of surface soils (depth: 0–5 cm) at 24 strip-like scarification-regenerated birch forests (15-41 years old) treated from the 1970s to the 1990s using a bulldozer with an attached rake. Soils from scarified belt showed significant decreases C and N contents and increase soil bulk density, but slightly decreases the C/N ratio. Lower C and N contents and higher bulk density were generally found in soils forming on non-volcanic materials. Moreover, with regard to the C contents and bulk densities, those differences in non-volcanic soils between scarified and non-scarified belts was significantly larger than those in volcanic soils. This study identified soil disturbance due to scarification in the scarified stands examined in this study (< 41 years old), in particular in area with non-volcanic materials. The findings can contribute to a better understanding of future scarification practices striking a balance between retaining soil resources and birch regeneration.
We investigated vegetation dynamics at clearcut sites to examine the effect of exclosures and/or culling of sika
deer. After weeding at two clearcut sites, exclosure fences were built and vegetation was assessed inside and outside of the exclosures at both sites. A total of 14 sika deer were culled at one of the sites and no culling was carried out at the other site. An unpalatable plant, Macleaya cordata, dominated the vegetation community at both sites initially. Species composition changed and cover of some plants, such as Rubus hirsutus increased rapidly inside the exclosure fence after weeding but did not increase outside the exclosure fence. Rubus and some other plants developed after culling of sika deer, but this change was muted at the site where no culling was conducted. Thus, Rubus can be an indicator plant reflecting browsing pressure by sika deer.
We report here a fungus gnat, Allactoneura akasakana Sasakawa, 2005, as found in indoor facilities of the shiitake mushroom, Lentinula edodes, from Japan and China. Adults and larvae were found in indoor facilities between September and November in Japan, without any infestations to fruit bodies of the mushrooms. Seven adults were trapped on seven of 1320 adhesive sheets installed in five facilities of Ibaraki and Gunma Prefectures, Honshu, Japan, from June 2017 until March 2019. Larvae collected on sawdust mycerial blocks in indoor facilities emerged as adults within two weeks after pupation at room temperature (around 20 degree of centigrade). Allactoneura akasakana was recorded from Tsushima, Okinawa Island, and China for the first time, based on adults collected in indoor and outdoor environments. We suggested that this fungus gnat is a potential pest of the shiitake mushroom, occurring with several generations during summer and autumn seasons in Japan and China.
I conducted bat-capture surveys for seven consecutive years (2004 - 2010) in a forest located in the south of Sapporo, Hokkaido. A total of 285 bats of six species, including Murina ussuriensis and Myotis ikonnikovi, were captured in 194 capture nights. Distinct sexual size dimorphism was observed in the body mass and forearm length of M. ussuriensis ; females were larger than males. Distinct sexual size dimorphism was also observed in the body mass of M. ikonnikovi ; however, the direction was opposite: males were larger than females. The body mass of female M. ussuriensis showed noticeable seasonal changes. It indicated that at the study site the parturition and nursing young occurred during July and that the young of the year began flying at the beginning of August. It also suggested the possibility that mother bats remarkably reduce body mass during the latter part of nursing period.
I surveyed the flora of wild vascular plants in Shikoku Research Center, Forestry and Forest Products Research Institute, which is located on a lowland hill in a warm-temperate zone, and revised the previous flora list published in 2006, following APG III system. As a result, 360 species, 277 genera, 110 families of vascular plants (38 of ferns, 6 of gymnosperm and 316 of angiosperm) are recorded. Thirty-nine species (10 of ferns, 3 of gymnosperm and 26 of angiosperm) are newly added. Shade-tolerant plants such as evergreen ferns (e.g. Crytomium fortune) and evergreen trees (e. g. Elaeocarpus zollingeri) and disturbance-adapted weeds (e.g. Sonchus asper) are newly recorded. It seems that the flora changes as the environment of the Shikoku Research Center changes with transplanting of the experimental forests and with the growth of the forests and the arboretum.