Hirokazu Yamamoto

Methane uptake and nitrous oxide emission in Japanese forest soils and their relationship to soil and vegetation types

Abstract To determine the means and variations in CH4 uptake and N2O emission in the dominant soil and vegetation types to enable estimation of annual gases fluxes in the forest land of Japan, we measured monthly fluxes of both gases using a closed-chamber technique at 26 sites throughout Japan over 2 years. No clear seasonal changes in CH4 uptake rates were observed at most sites. N2O emission was mostly low throughout the year, but was higher in summer at most sites. The annual mean rates of CH4 uptake and N2O emission (all sites combined) were 66 (2.9–175) µg CH4-C m−2 h−1 and 1.88 (0.17–12.5) µg N2O-N m−2 h−1, respectively. Annual changes in these fluxes over the 2 years were small. Significant differences in CH4 uptake were found among soil types (P < 0.05). The mean CH4 uptake rates (µg CH4-C m−2 h−1) were as follows: Black soil (95 ± 39, mean ± standard deviation [SD]) > Brown forest soil (60 ± 27) ≥ other soils (20 ± 24). N2O emission rates differed significantly among vegetation types (P < 0.05). The mean N2O emission rates (µg N2O-N m−2 h−1) were as follows: Japanese cedar (4.0 ± 2.3) ≥ Japanese cypress (2.6 ± 3.4) > hardwoods (0.8 ± 2.2) = other conifers (0.7 ± 1.4). The CH4 uptake rates in Japanese temperate forests were relatively higher than those in Europe and the USA (11–43 µg CH4-C m−2 h−1), and the N2O emission rates in Japan were lower than those reported for temperate forests (0.23–252 µg N2O-N m−2 h−1). Using land area data of vegetation cover and soil distribution, the amount of annual CH4 uptake and N2O emission in the Japanese forest land was estimated to be 124 Gg CH4-C year−1 with 39% uncertainty and 3.3 Gg N2O-N year−1 with 76% uncertainty, respectively.

Ribosomal resistance of an istamycin producer, Streptomycestenjimariensis, to aminoglycoside antibiotics

Abstract Streptomyces tenjimariensis SS-939 was resistant to its own aminoglycoside antibiotics, istamycins, as well as kanamycin A, neamine, ribostamycin and butirosin A, but was susceptible to neomycin B, lividomycin A and streptomycin. This resistance to these antibiotics was found to be due to ribosomes of the strain.

Two thirds of forest walkers with Japanese cedar pollinosis visit forests even during the pollen season

BACKGROUND The most common type of pollinosis in Japan is Japanese cedar pollinosis (JCP). While forest walking is a common form of recreation for Japanese people, it has been unclear whether forest walkers with JCP still choose to visit forested areas during the pollen season or whether they avoid those areas, and as such, the aim of this study was to investigate this question. METHODS The study participants were all healthy men and women volunteers aged 20 years or over who visited the Tokyo University Forest in Chiba during 4 different days. The survey was conducted using self-administered questionnaires. RESULTS The number of available responses was 498. Of these, 112 participants who experienced JCP were included in the analysis. Seventy-three participants (65.2%) responded that they visit forests even during the pollen season. The association between forest walking choices during the pollen season and self-rated levels of pollinosis symptoms was not statistically significant (Cramers V = 0.13, p = 0.47). As many as 60% of the participants who reported serious symptom levels responded that they visit forested areas even during the pollen season. CONCLUSIONS These results revealed that two thirds of forest walkers who had experienced JCP visited forests even during the pollen season. This indicates the further need for public service announcements informing people with JCP that the risk of pollen exposure and subsequent JCP reaction is increased by visiting forested areas during the pollen season.

Application of a tri-capital community resilience framework for assessing the social–ecological system sustainability of community-based forest management in the Philippines

This study proposes and empirically tests a framework that integrates the concepts of community resilience and social–ecological system (SES) resilience through community forestry case studies. The framework provides a possible approach for assessing community resilience based on the development and allocation of socio-cultural, economic, and natural capital of individual households within a given forest community. Furthermore, aspects of SES resilience and system dynamics are used to define the potential state thresholds of community resilience. This exploratory attempt to quantify community resilience, using the proposed framework, aims to advance understanding of the conceptual overlaps of SES and community resilience as applied to forestry management. We consider community forestry groups as SES examples in which the community is an important stakeholder in managing natural forest capital. We selected pioneer communities under the community-based forest management (CBFM) Program in the Philippines as our case studies. We found that, on average, CBFM group members demonstrated moderate levels of resilience according to their acquired levels of capital. Although economic capital remained the weakest capital, the CBFM program had a positive effect in increasing the socio-cultural and natural capital of an entire community.

Object-based larch tree-crown delineation using high-resolution satellite imagery

Olgan larch is a traditional construction material used for the renovation of historical timber-frame buildings in China. However, acquiring the necessary large-sized larch trees from old-growth forests has become a challenge in China because of the rare and inaccessible distribution of these trees. In recent years, remote sensing imagery has provided a more effective alternative for delineating tree crowns automatically with high accuracy. In this study, an object-based method for delineating old-growth larch tree crowns using Geoeye-1 imagery is developed. Tree crown delineation results are tested and evaluated by field data. In addition, the correlation between delineated tree-crown and basal areas are quantitatively validated to ensure that the developed method can be applied for estimating the distribution of old-growth larch trees. Results demonstrate that the developed object-based larch tree-crown delineation method is reliable, thus providing a new technique for detecting old-growth larch tree resources in Northeastern China.

Estimating the Volume of Large-Size Wood Parts in Historical Timber-Frame Buildings of China: Case Study of Imperial Palaces of the Qing Dynasty in Shenyang

Abstract Timber-frame buildings are an important architectural heritage of China, and they play a pivotal role in Chinese architectural history. However the restoration of wood components in ancient buildings has gained significant importance in recent years. Based on the modular theory of ancient Chinese architecture this research includes a case study on the Shenyang Imperial Palace, in order to determine a correlation between the volume of large-size wood parts and the building areas. Linear regression equations have been derived to estimate the volume of large-size wood parts efficiently, and the total volume of the large-size wood parts of the Shenyang Imperial Palace has been estimated as 2912.3 m3. It was found that the regression equations for the flush gable roof type buildings are accurate and can be applied not only to the case study in particular but also to other buildings as well. Finally, determining the volume will bridge the communication gap between the people concerned with restoration and the timber suppliers, which is an increasing concern in China with regard to preservation of ancient buildings and historical monuments.

Inhibitory Effect of Colicin E2 on Transport Systems of Escherichia coli in the Presence of the rex Gene of λ Prophage

Purified colicin E2 was found to cause marked inhibition of the permeation rate of o-nitrophenyl-galactoside (ONPG) in several λ-lysogenic strains of Escherichia coli in the presence of chloramphenicol to prevent prophage induction. The inhibitory effect of colicin E2 on transport systems was analyzed with cells of E. coli CP78(λ). The dose of colicin E2 for the half-maximum inhibition of the ONPG-permeation rate was about 9 molecules of the colicin per bacterium under the aerobic condition, which corresponded to about 1 killing unit per bacterium. Kinetics of the transport of [14C]methylthiogalactoside suggested that colicin E2 began to inhibit the influx rate of β-galactosides within a few minutes after the colicin addition, and the maximum inhibition reached more than 80%. Extensive leakage of intracellular potassium ion and inhibition of l-proline transport also occurred at the same time. Acid solubilization of cellular deoxyribonucleic acid by the colicin was apparently delayed to the initiation of the transport inhibition. The extents of the inhibition of β-galactoside transport and leakage of potassium ion by the colicin were extensive in cells lysogenic for wild λ phage or λind−, whereas the extents were slight in the nonlysogenic cells or cells carrying λrex− prophage. It was concluded that the sensitization of membrane transport systems of E. coli cells to colicin E2 was achieved by the presence of the rex gene product of λ phage.

Overmature periurban Quercus–Carpinus coppice forests in Austria and Japan: a comparison of carbon stocks, stand characteristics and conversion to high forest

Periurban coppice forests have a long history and tradition in Austria, as well as in Japan. Although developed in a slightly different context, such forests faced nearly the same fate during the last century. While these once served biomass almost exclusively as a feedstock for thermal energy, their significance decreased with the increasing use of fossil fuels and coppice management was consequently abandoned, or these forests were converted into high forests with different management aims. This study tries to assess the status of periurban forests that were previously managed as coppice in a comparative approach between Vienna (Austria) and Tokyo (Japan) in view of rising demands for biomass. The focus is to present stand structure, biomass and C stocks, as well as a comparison with high forest in typical stands close to the urban area. In Japan, we further directly assessed the consequences of coppice to high forest conversion on soil chemistry. While lower diameter classes are dominated by Carpinus, Quercus is only found in larger diameter classes, indicating the overmature character of both stands due to the lapse from a recognized system of coppice management with occasional fuelwood harvesting in the past decades. Total C stocks are comparable, but soil organic carbon is significantly higher in Japanese Andosols. The conversion of coppice to high forest in the 1960s in Japan had a notable impact on soil chemistry in our plots. There may be multiple benefits for restoring coppice management to these periurban forests. This includes increased biomass production capabilities and carbon sequestration as well as a better habitat provision and a higher biodiversity.

Indexing of spatial patterns of trees using a mean of angles

The assessment of information relating to the spatial patterns of individual trees is becoming an increasingly important aspect of forest research and practical forestry. Numerous methods have been proposed over the years, with foresters preferring rapid methods able to provide statistically confident information. The Mean of Angles is one of the simplest of these methods. It is applicable for revealing complete spatial randomness (CSR) or the presence of clustering or regularity. We have tested the potential of the arithmetic mean of angles to serve as a practical measure of the degree of regularity or clustering. This study was conducted by applying random point sampling in various simulated theoretical point populations. The Mean of Angles method deserves consideration as a practical option for examining the spatial patterns of trees in forests. We suggest that the arithmetic mean of angles cannot be completely relied upon for indexing spatial patterns, but this deficiency can be overcome by examining the frequency distributions of angular measurements.

The effect of bark decortication for hiwada production on xylem and phloem formation in Chamaecyparis obtusa

Of all plant materials used to cover the roofs of traditional Japanese buildings, Japanese cypress (Chamaecyparis obtusa) bark, hiwada, has the longest service life and has been used from ancient times. However, wood and bark properties after hiwada harvest have not been evaluated in detail. We studied whether decortication for hiwada production in winter affected xylem and phloem formation. Decorticated trees still preserved all inner bark and part of the outer bark, and both decorticated and control trees had similar annual ring structures at all stem heights in the xylem and phloem. In both xylem and inner bark, no significant difference in ring width at any stem height was found between annual rings before and after decortication. Thus, this study revealed that the decortication of bark for hiwada production does not affect the formation of xylem and the inner and outer bark if decortication is carried out by highly skilled workers in winter.