Bamboo forests are distributed across sites with various natural and social properties, although distribution patterns and site properties vary widely with regions and periods studied. Abandoned Bamboo Forests (ABFs) have been invading the adjacent lands since the bamboo industry had declined in 1980s. Bamboo can invade sites with various natural properties such as slope degree, slope position, land-use types and so on, leading that ABFs has increased their area largely. Expansion of ABFs also are affected by human impacts as well as the land-use types neighboring the ABFs. Studies on awareness about the expansion of bamboo forests for local residents showed that the many residents recognized that expanded bamboo forests have been abandoned but had less recognition that many bamboo forests have been expanding. Further, urban and suburban residents had different opinions about the ecosystem services bamboo forests provide. Ecosystem services such as habitats for wildlife and carbon stock have deteriorated in ABFs. To enhance ecosystem functions of ABFs, various techniques could be used such as constructing the new uses for bamboo culm and effective logging methods. In order to use ABFs as part of green infrastructure, establishment of long-term management systems that can be enhance ecosystem services of ABFs are important.
Range expansion of unmanaged invasive Phyllostachys bamboo stands is one of the most serious problems in ecosystem management in Satoyama area across Japan. It is feared to be accelerated by depopulation and climate change. In this study, we analyzed changes in vegetation and land use by using aerial photography between 1977 and 2014 in a deserted area in Ikusaka village, Nagano Prefecture, central Japan. We also conducted field surveys in 2017, 2018, and 2020. Consequently, the areas of bamboo stands were estimated to have expanded 13.54 times from 0.26 ha of 3 stands in 1977 to 3.52 ha of 17 stands in 2014. The annual expansion ratio of the whole area was estimated to be 1.073 ha·ha-1·year-1, which was in the range (0.96-1.11) of those previously reported majorly for moso bamboo (Phyllostachys edulis). Among the 17 bamboo stands recognized in the aerial photography in 2014, 14 were identified as hachiku (P. nigra var. henonis) and 3 as madake (P. bambusoides) bamboos by the field surveys. The annual expansion ratios of individual stands that were comparable between 1977 and 2014 were 1.016, 1.056 (for 2 hachiku stands), and 1.036 (for 1 madake stand). These results imply that there are risks of range expansion of hachiku and madake bamboos even in cooler hilly and mountainous areas comparable to those of moso bamboo in western Japan.
I evaluated moso bamboo Phyllostachys edulis growth and wild animal activity in a bamboo stand in Kyoto, western Japan, during 2016-2019. The aboveground biomass increment of the moso bamboo stand, an index of bamboo growth, was consistently negative throughout the study period, presumably due to limitations on the production of new bamboo shoots. Using camera traps, I frequently observed damages to moso bamboo shoots by wild boar Sus scrofa and sika deer Cervus nippon between March and May, which led to growth failure for new bamboo shoot production. This report highlights the possibility that wild animal activity may inhibit moso bamboo growth in naturalized moso bamboo stands in Japan.
Bamboo forest expansion is a well-known problem, not only in Phyllostachys pubescens but also in P. bambusoides. The conversion of abandoned bamboo groves to broadleaf forests is desirable for ecosystem function. We first investigated the effects of sodium chlorate (Chlorate S) on plant germination following disturbance by conducting a three-month sowing test. Next, we established three plots in an abandoned P. bambusoides stand in Chiba Prefecture, Japan, in May 2013 to compare the changes in vegetation over 5 years. To prepare the plots, clear-cutting of bamboo culms was carried out in all plots and chemical treatment was applied to two for examining the effects of chemical treatment on revegetation. The results of the sowing test showed the presence or absence of the chemical had no significant effect on the number of germinated species, although the response to the chemical was species-dependent. The density and average diameter of regenerated bamboo culms were lower in the chemically-treated plots than in the untreated plot. In the chemically-treated plots, bamboo culm regeneration was suppressed after September 2013, whereas other plants grew abundantly. Regenerated bamboos thrived in the non-treated plot until October 2014, after which other plants increased. By the third year, broadleaf trees were growing in all plots. The chemical treatment did not almost affect the growth of seedling-derived trees adversely and few differences in species composition emerged between treated plots and the untreated plot. Our study demonstrated that it is essential to leave as many woody species as possible when clear-cutting culms and that chemical treatment can also be an effective method for forest conversion.
We applied select herbicides, chlorate and glyphosate, upon invasive bamboo forests and then monitored the herbicidal residue present within the fallen leaves, fine roots, soil, and stream water of the forests in question. In addition, we examined the effects of herbicides on seed germination and the understory vegetation within the bamboo forests studied. The herbicide chlorate nearly degraded completely within a one month period within the soil, whereas the herbicide glyphosate was slightly detected at low levels within the bamboo forest leaf fall, fine roots, and the soil. Simultaneously, none of the two applied herbicides were detected within nearby stream water during the assessment period. The possibility of herbicidal outflow from the application area is considered to be low. Among three tree species which are widespread within clearcutting sites, or the understory of bamboo forests, the germination rate of Zanthoxylum ailanthoides significantly decreased following the application of the herbicide chlorate. Furthermore, the understory vegetation within the bamboo forest was additionally surveyed in order to assess the effects of glyphosate application upon the vegetation. Following the application, vegetation coverage increased rapidly, reaching nearly double the amount of prior coverage before application across number of species, which included pioneer trees and herbs. It is assumed that glyphosate application caused effects akin to clearcutting via killing bamboos, since similar vegetation dynamics were reported within clearcutting sites. Taking all factors into account, the negative environmental impact of the select herbicides applied to bamboo forests should be limited in scope.
Vegetation map is an essential material in regional/local planning as well as environmental assessment, and it has been created by phytosociological field survey with an aid of aerial photographs and/or satellite images. The UAV (unmanned aerial vehicle) becomes strong tool as low altitude remote sensing (LARS) in vegetation mapping, because it can provide high resolution images whenever and wherever desired. An aim of the study is to develop a technology of vegetation mapping for local planning, through a case study at a forest in Tkaragaike Park of Kyoto City, Japan. Phytosociological survey was conducted at 74 locations in the forest from 21 to 23 of June 2019, and 7 plant communities were distinguished based on species composition and vegetation height; Pinus densiflora - Rhododendron reticulatum community, Quercus serrat - Q. variabilis community, Castanopsis cuspidata community, Cryptomeria japonica - Chamaecyparis obtusa plantation and their sub-communities. Prior to the phytosociological survey, aerial photographs were taken by using UAV from March to May in 2019. Near-infrared sensor was used to take aerial photographs in March, because the season was easy to distinguish the boundaries of evergreen- and summer green-type forests, and to find evergreen trees under the canopy of deciduous trees. Normalized difference vegetation index (NDVI) was also calculated from the images to evaluate a density of evergreen trees. May is the blooming season of C. cuspidata and thus it is suitable to identify its area. Using the Digital Surface Model (DSM) produced from the LARS images and Digital Terrain Model (DTM) provided from Kyoto City, the canopy height model (CHM) was created. The location of every individual of P. densiflora was identified from the LARS image by a method of deep learning, and the density of P. desiflora was calculated in a circle with 10 m radius from every tree of P. densiflora. By linking those spatial attributes obtained from LARS images with attributes of phytosociological communities, vegetation boundaries were fixed and map was produced. The method developed in the study is cost-effective and applicable to any other areas.
Roadkill (RK) refers to wildlife killed as a result of the collision with a vehicle. RK prevention is an important issue not only for environmental conservation but also for safe driving. In this study, we focused on RK records (RKR). RKR is an invaluable source of biological information that provides the basis for solving RK problems. The RKR can be used to identify RK hot spots, analyze the causes of its occurrence, propose preventive countermeasures, and understand the animal habitat. Moreover, RKR is big data with a large amount and variety. Therefore, the systematization of records is important. Previous studies have reported the content and management of RKR; thus, this study focuses on the current situation and issues of the RKR in Tottori Prefecture. Besides, future RKR improvements and methods are also proposed. Data on RKR were collected through interviews via phone, e-mail, and direct visits to related organizations such as road administrators, police department, prefectural departments that rescue injured birds and mammals, and local museums during the period from 2018 to 2019. Consequently, it was found that some organizations did not record RKR and even if it was collected, the data are too few to meet the need for countermeasure implementation and scientific analysis both from qualitative and quantitative points of view. One of the main reasons for insufficient records is the RK status in each organization. Nearly all organizations (except highway road administrators) did not utilize RKR for countermeasure implementation and analysis. In the future, it is desirable to improve the content and format of RKR, considering the importance and burden of RKR in each organization. Establishment of a suitable RK recording system and enactment of favorable RK policies are of paramount importance for the alleviation of RK.
The Northern Goshawk (Accipiter gentilis Linnaeus 1758), a rare raptor, is listed as an near threatened (NT) species on the red lists by the Ministry of Environment of Japan. Many guidelines about how to manage the forest have been suggested for habitat conservation of the Northern Goshawk, and suggested that active forest management is required to maintain appropriate habitat conditions for extended periods. However, there are few cases of actual active management in Japan. The aim of this study is to evaluate the effectiveness of the active forest management implemented in “The Forest of Accipiter gentilis, Daisen, Tottori Prefecture” by comparing the forest structure and avifauna before and after forest management and to suggest an appropriate management plan. A management plan (Management of pine tree density, improvement by cutting of broad-leaved trees that reached the sub-tall tree layer) was suggested based on the first survey by the Tottori Chapter of the Wild Bird Society of Japan and Tottori University in 2003, and this suggestion was implemented by Tottori Prefecture for the five ensuing years. A second survey, conducted after the management, revealed that pine trees with a large diameter at breast height (DBH) and open spaces between the canopy and understory foliage for flying were preferred as nest areas by the Northern Goshawk. In addition, there was a good foraging range around the case study area. The mosaic of farmland and forest of the Satoyama range was utilized by the Northern Goshawk for foraging. Forest management that includes (1) promoting growth of large diameter trees for nesting and (2) securing flight space in the forest was made clear appropriate for both the conservation of Northern Goshawk habitat and timber cultivation.
Significance of emotionally engaging factors such as fun or aesthetics has been pointed out in order to promote the spread of Green Infrastructure. One of the fine examples are "Artful Downspouts" whose design can appeal additional values and meanings of beauty, fun or enlightenment though the function of conveyance of run-off is the same as the ordinal ones. As there is no comprehensive report about "Artful Downspouts", this research organized the following information by collecting the photos via online: variety of design types, kinds of functions, distribution and increase rate. 351 photos were found in total. The location of 162 photos were revealed, of which 119 were in the United States. Most photos were found in the cities which had proactively introduced green infrastructure. The classification of design types was proposed from the information of changing parts of downspouts. As the result of summary counts based on the classification, 64 % of "Artful Downspouts" were made by altering the forms of the end of pipes or swapping the rain chains. It indicates the importance of easiness of installation. The design of 27 % had little relation with flood alleviation or nature conservation. It implies that "Artful Downspouts" could incorporates diversity of interest and its non-exclusiveness might have contributed to the dissemination of Green Infrastructure.
Edible wild plants, Sansai as an ecosystem service are possible resources to enhance regional development for depopulated regions. Sansai has been sold at roadside stations called as Michi-no-Eki. The amount of Sansai sold at the roadside station is considered to be determined by the purchasers and by availability of Sansai in the area. The availability is probably affected by land mosaic, proximity between residents and (semi-)natural lands.
We got the data of sales of Sansai 22 road side stations, Michi-no-Eki in Gifu and Aichi Prefectures in 2016, and analyzed geographic conditions that affect sales and items of Sansai. Geographical conditions affecting item composition and sales were analyzed by simple correlation analysis, generalized linear models (GLM).
As a result, 33 kinds of wild plants were sold. The number of units sold per roadside station had a positive correlation with the number of items sold and the number of users, and a negative correlation with the distance from the population center of the nearest-large city, Nagoya. The number of users had a negative correlation with the distance from the center of population. In the GLM analysis using the number of sales per user as the response variable, the model that included only the number of items as the explanatory variables was the best model with the smallest AIC. On the other hand, there was no significant correlation between the number of items and regional attributes such as land use diversity and population density, but a model with a quadratic curve with a high distance of about 115 km from the city was selected by GLM.
The number of Sansai sold was affected by the number of visitors and the number of items sold. The former is mainly affected by the distance from the city center, so it is difficult to improve it. However, the latter is expected to be improved by roadside stations and sellers.