The profitability of a biomass power station is low because its installation cost and fuel cost are high and its power generation efficiency, around 25%, is lower than the efficiency of an LNG power station, about 50%. On the other hand, the profitability of a combined heat and power (CHP) could be higher since it sells both electricity and heat. To prove the profitability of a CHP plant, we developed a tool for assessing profitability on a steam turbine CHP system using wood biomass. Then we assumed four plant sizes, i.e. maximum power output 1,200, 1,600, 1,999, and 5,700 kW, and simulated the internal rate of return and other factors, under the following three scenarios: 1) stand-alone (without heat supply), 2) CHP with steam supply and 3) CHP with hot water supply. We decided two heat prices, 7.7 and 5.2 yen/kWh, referring to the heavy oil price. We found the following results: a) The profitability of CHP became higher than that of the stand-alone case. b) In the case of the 1,200 kW plant, the CHP project could not make a profit under the lower heat price because of its lower power generation efficiency. c) The profitability of CHP with hot water supply became higher than that of CHP with steam supply because the decrease of power output by steam extraction was smaller. d) Larger heat demand is necessary to make the profitability of CHP higher.

This paper provides a full picture of the current status and movements of the forest use of trail running in Japan, based on interviews with the runners who lead its popularization and conflict resolution with other users. Trail running has become popular in Japan since the 2000s as a new type of recreational use of forests, reflecting the massive information available on trail running resulting from conducting major races, the steep increase in the number of runners due to the increase in marathons and fitness trends, and the growing trend of outdoor recreation, especially among the middle-aged population. However, trail running was also subjected to a lot of criticism by hikers, conservationists, and landowners, who pointed out the potential accidents and environmental damage that could take place from the sudden increase in the numbers of trail runners and races. These conflicts resulted in some of the current restrictive regulations toward the forest use for trail running, such as “Rules for Using Nature Parks” issued by the Tokyo Metropolitan Government in 2015. To efficiently handle these conflicts, many leaders of trail runners shared the need for runners’ unified cooperation, and founded the Japan Trail Runners Association to spread awareness among the trail runners and secure their social status. In addition, multiple projects, such as conducting trail running races and tours as well as renewing or maintaining trails, have been carried out by these leading runners through their strong collaboration with the local governments and communities suffering from declining populations in the rural mountain areas to support the local revitalization.

Mass mortality of oak by Japanese oak wilt disease is caused by an ambrosia beetle vector, Platypus quercivorus. In northern Gunma Prefecture, a geographically isolated mass mortality occurred in Minakami in 2010 for the first time. We hypothesized three origins of the beetle population causing the isolated mass mortality: (1) a population recently migrated naturally or artificially from near or neighboring prefectures, which might exhibit a low genetic diversity due to founder effect; (2) a recently artificially migrated population from a distant area, which might have genetically different lineages and a low genetic diversity due to founder effect; and (3) an indigenous population, which exhibits a relatively high genetic diversity. We examined these hypotheses using variations of nuclear ribosomal DNA (rDNA), mitochondrial DNA (mtDNA), and nuclear microsatellite (nSSR) for Gunma and six other neighboring or nearby prefecture populations. Genetic structures of rDNA and nSSR showed that the Gunma population belonged to a northeastern Japanese Sea of Japan-side lineage, as had neighboring prefecture populations, indicating that the Gunma population did not recently migrate from a distant area with different lineages through human activity. Genetic diversity of mtDNA and nSSR indicated that the Gunma population exhibited a moderate genetic diversity, similar to the other populations. Therefore, we concluded that the Gunma population might have originated from an indigenous population.

The study aimed to clarify the influence of the nuclear disaster on the wood supply and demand and the present situation of forestry and wood industry in Fukushima. Reconstructing the facilities damaged by tsunami and earthquake was partly completed, however, the aftermath of it remains yet. After the disaster, the wood demand rate greatly increased, nevertheless the amount of material production stagnated, so that the imported wood ratio from other prefectures exceeded. The timber price slightly differed from the country's trend, the increase rate was low, and price of roundwood and stumpage price and gross forestry output production decreased than before. In comparative analysis across the areas, the timber demand declined in Soso area in which Fukushima Daiichi Nuclear Power Plant was, and the supply and demand balance was also altered in other areas. The restriction of forestry management owing to the nuclear disaster and the wood price fall stalled the material production and changed the balance of wood production and distribution in Fukushima. Whereas the reconstruction has been progressing in midstream and downstream, the deterioration of management in upstream is getting worse. To reconstruct forestry, measures are needed to improve the upstream process with consideration of situation in Soso area.

Various studies have examined the effectiveness of Nature Experience Activities. In this one, we examined the influence of Ikiru Chikara and Symbiotic Values with Nature on children participating in Nature Experience Activities in a forest environment. This research focused on the characteristics of participants and examined the effect of the program in terms of the impact of the original nature experiences and the mental and physical trauma of adverse experiences of natural disasters. The subjects analyzed were 213 participants in Fukushima Kids Program and their parents, all of whom were asked to provide feedback via questionnaires on aspects of Ikiru Chikara, Symbiotic Values with Nature, nature experiences and the experiences of parents during the disaster. After analyzing Symbiotic Values with Nature, the three factors emerging included an affinity with nature, relationship between nature and life and interest in and consideration of nature. The analysis of all participants showed that the program improved both Ikiru Chikara and Symbiotic Values with Nature. This improvement was clear following a comparison made with children with less experience of nature. What also emerged was how the occurrence or absence of a fearful experience caused by on earthquake affected on the level of physical ability.

In Japan, the origin of the forest planning system can be traced back to two events which made a major impact-namely, the 1939 amendment of the Forest Law and the formulation of the forest policy during the Allied occupation of Japan under the General Headquarters/Supreme Commander of the Allied Powers (GHQ/SCAP). My research involved the analysis of the present forest planning system as well as the discourse of policymakers involved in it. It can be concluded that the 1939 amendment to the Forest Law extended the scope of the forest management plan to private forests as well, and was the basis for the current forest planning system which includes technical mechanisms such as forest registers. At the same time, the evaluation of the 1939 amendment of the Forest Law is a point of contention among policymakers, especially with regards to the wartime regime. For this reason, the significance of the 1939 amendment of the Forest Law may have been underestimated after World War II. With regard to the policy under the Allied occupation, the “forestry program” as given in the GHQ/SCAP document provided an accidental opportunity for the formulation of a forest planning system. Revisiting the discourse of policymakers of that period, it can be inferred that as a result of political horse-trading with the occupation policy, the forest planning system formulated at that time laid the foundation of forest policy in Japan after the war.

We investigated the height and suppression status of planted trees in young sugi (Cryptomeria japonica) plantations that were weeded every year in Yame, Fukuoka, Japan, to develop a criterion to determine the need for weeding. Plantations with varying competing vegetation types were studied, and the height of competing vegetation that had recovered one year after weeding differed with variation in the dominate species. Miscanthus (Miscanthus sinensis) exhibited high recovery values, while the recovery heights of three major component species of the competing vegetation (M. sinensis, Rhus chinensis and Mallotus japonicus) were almost the same within each species irrespective of the number of times of weeding (i.e., years after planting). The planted sugi trees tended to be released from suppression according to their height. However, the degree of the release was different for the different vegetation types; generalized linear models demonstrated that sugi needed to be taller in the miscanthus-dominated type than other vegetation types to achieve the same degree of release from suppression. These results suggest that there is no depression of the recovery height for major weeds or trees caused by repeat weeding, and that the weeding criterion should vary with vegetation types, according to their respective post weeding recovery potential. With the assumption that weeding is needed when 90％ of planted sugi tree are taller than surrounding competing vegetation, the critical height of sugi trees is 2.2 m for the miscanthus-dominated type and 1.4 m for the other vegetation types.

This study aimed to estimate the tree height and volume based on image data, which are obtained by conversion of the sound generated from hammering a stem using deep learning. We hammered 20 trees 100 times, recorded the hammering sound, and generated the spectrogram, which presented the sound pressure at each frequency for 0.6 s. Data comprising 10,000 images were loaded into a deep learning model. We used the Neural Network Console (NNC) as the deep learning system and the LeNet, which forms a programmed regression layer to an output layer, as the deep learning algorithm. We divided 10,000 images into 5 equal sets, and performed three learning patterns (LP-I, LP-II, and LP-III). LP-I used the four sets as training data and the remainder as test data, LP-II used three trees and LP-III used six trees, which select for each tree from three divisions (large, medium, small), as test data. A performance evaluation of the proposed model was performed using three indicators: mean absolute error (MAE), mean absolute percentage error (MAPE), and coefficient of determination (R²). Each learning pattern provided very good estimates (R² values for each learning pattern for the test data ranged from 0.9192 to 0.9996), except for the height estimate by LP-III (R²＝0.3672). LP-III generated very poor height estimates with a bias and tended to underestimate by > 30 m and overestimate by < 30 m. However, each learning pattern provided a good estimate of the tree volume, generally without any bias. Thus, we found this method to be more effective for estimation of tree volume than tree height.

As the world's forest area continues to decline, China's forest area has consistently increased since the 1980s. In this research, we clarified the driving force behind this by focusing on the socio-economic factors of China. There is much previous research on the relationship between socio-economic factors and forest resources in various countries. However, the methods used for research in this field are mainly panel data analysis, and the results produced using such tests, for example unit roots and cointegrations of time series data, are limited. In this research, we used the time series data for the last 40 years on forest area and socio-economic factors in China, and we used an autoregressive distribution lag (ARDL) model considering the stationarity of variables and the cointegration relationship. Unit root tests show that all variables are either stationary or becoming stationary after the first differencing. The estimation results show that the change rate of GDP per capita has a positive impact on the change rate of forest area in the short-run but a negative impact in the long-run, and that the change rate of rural populations has a negative impact in both the short- and long-run. It was also shown that the change rate of urban population and foreign direct investments in China have a positive impact on forest coverage rates in the short-run.

Thematic maps, such as forest change and land cover change maps, are generally inaccurate. The assessment of accuracy, defined as the correctness of a map, is critical for understanding the quality and utility of thematic maps. This review shows the fundamental principles in area estimation and accuracy assessment for forest change maps based on three components: sampling design, response design, and analysis, and then reveals the criterion and recommended practices. Several special cases of accuracy assessment are also discussed. A probability sampling design is implemented in the statistically rigorous accuracy assessment to estimate accuracy based on the comparison of a map and reference data. Population error matrix is crucial in assessing the accuracy and estimating area. Further, the use of unbiased or consistent estimators that correspond to the sampling design is critical for deriving accuracy metrics and area estimates with associated uncertainty. Although the fundamental principles of accuracy assessment are well established, methods for addressing issues have also recently been developed. Practitioners are required to choose the optimal protocols to achieve their objectives of the accuracy assessment because no single protocol or approach can completely address all situations.