Current main research interests are chemical structure, function, and dynamics of natural organic matter, in particular humic substances, dissolved organic matter (DOM), and black carbon (C). An accumulation of organic matter or C in soil is very important in both aspects of global C cycle/balance related to global warming and improvement of soil fertility (plant production ability). Stabilization process of soil organic matter and relationship between degradation rate and structural property of natural organic matter are studied. Effects of forest type, land use type, or soil type on the quality and quantity of DOM and DOM-metal complex, which are exported from pedosphere to hydrosphere and essential for maintaining aquatic ecosystems, are also investigated. Other research topics include dynamics of silicate in a rice paddy and sustainable agricultural use of tropical peatland.

Recent Publications:

1. Ikeya, K., Sleighter, R.L., Hatcher, P.M., and Watanabe, A. 2015: Characterization of composition of soil humic acids using Fourier transform ion cyclotron resonance mass spectrometry. Geochim. Cosmochim. Acta, 153, 169-182.
2. Kawasaki, S., Ikeya, K., Sugiura, Y., and Watanabe, A. 2015: Changes in the composition of humic acids in various upland field soils with a continuous organic amendment as revealed by fractional precipitation analysis. Soil Sci. Plant Nutr., 61, 450-460.
3. Watanabe, A. 2015: Cultivation management and environment. In The Sago Palm―The Food and Environmental Challenges of the 21st Century. Ed. The Society of Sago Palm Studies, p. 191-198, Kyoto Univ. Press, Kyoto, Japan.
4. Watanabe, A., Ikeya, K., Kanazaki, Y., Makabe, S., Sugiura, Y., and Shibata, A. 2014: Five crop seasons’ records of greenhouse gas fluxes from upland fields with repetitive applications of biochar and cattle manure.J. Environ. Manage., 144, 168-175.
5. Watanabe, A., Tsutsuki, K., Inoue, Y., Maie, N., Melling, L., and Jaffe, R. 2014: Composition of dissolved organic nitrogen in rivers associated with wetlands. Sci. Total Environ., 493, 220-228.

The main goal of research in this laboratory is to understand the water, energy, CO₂, and other mass cycles, and the relationships between these cycles and the biome. The main subjects of our research and education are forest/mountain hydrology, forest/mountain meteorology, and soil erosion control engineering.

Our research is divided into five areas:

1. Water, energy, and CO₂ exchanges between the atmosphere and the biome in multi-scale The results of this research will contribute not only to the understanding of water, energy, and CO₂ exchange processes in spatial scales of from a leaf, canopy to region, and the effects of physiology on these cycles, but also to the prediction of global changes.
2. Evaluation of water cycles on a watershed scale The water cycle system is investigated using several experimental watersheds. The results will contribute to both the physical understanding of run-off systems and the prediction of landslides and debris flow.
3. Hydrometeorological characteristics of sub-alpine mountains The hydrometeorological conditions of sub-alpine mountains are quite different from those in hilly mountains. Our main goals are to estimate the spatial and temporal distributions of meteorological elements throughout the year, and to understand snow accumulation and ablation processes in high mountain areas by using a new model and remote-sensing data.
4. Hydrometeorological characteristics of urban environment In urban or suburban areas where human activities change land surface conditions variously, hydrometeorological effects of complex land use including urban vegetation are investigated.
5. Sediment yield in a mountain watershed The characteristics of sediment yield from a watershed, and watershed conditions such as vegetation, topography, and geology, are investigated. Our results will contribute to watershed management and river planning.

Recent publications:

1. Ohta, T., Hiyama, T., Tanaka, H., Kuwada, T., Maximov, T. C., Ohata, T., and Fukushima, Y. (2001) Seasonal variation in the energy and water exchanges above and below a larch forest in Eastern Siberia. Hydrological Processes, 15, 1459-1476.
2. Matsumoto, K., Ohta, T., Irasawa, M., and Nakamura, T. (2003) Climate change in extending the growing season of Ginkgo biloba L. in Japan. Global Change Biology, 9, 1634-1642.
3. Hamada, S., Ohta, T., Hiyama, T., Kuwada, T., Takahashi, A., Maximov, T. C. (2004) Hydrometeorological behavior of pine and larch forest in eastern Siberia. Hydrological Processes, 18, 23-39.
4. Tanaka, T., Hattori, S. and Park, H. (2004) Measurement of forest canopy structure by a laser plane range-finding method. Improvement of radiative resolution and examples of its application. Agricultural and Forest Meteorology, 125, 129-142.
5. Kotani, A., and Sugita, M. (2005) Seasonal variation of surface fluxes and scalar roughness of suburban land covers. Agricultural and Forest Meteorology, 135, 1-21.
6. Matsumoto, K., and Ohta, T. (2005) Evaluation of the effect of leaf physiological activity on the behavior of stomata by using leaf chlorophyll concentration. Agricultural and Forest Meteorology, 132, 44-57.
7. Toba, T., and Ohta, T. (2005) An observational study of the factors that influence interception loss in boreal and temperate forests. Journal of Hydrology, 313, 208-220.
8. Maeda, K.,Tanaka, T., Park, P., and Hattori, S. (2006) Spatial distribution of soil structure in a suburban forest catchment and its effect on spatio-temporal soil moisture and runoff fluctuations. Journal of Hydrology, 321, 232-256.
9. Kotani, A. and Sugita, M. (2007) Variance methods to estimate regional heat fluxes with aircraft measurements in convective boundary layer. Journal of Hydrology, 333, 68-85.

Studies of our laboratory cover a wide range of research themes closely relating to forest ecology, forest genetics, and tree ecophysiology.

The research projects can be divided into the following four major topics concerning forests and forest trees:

1. Forest structure and dynamics;
2. Genetic diversity and population genetic structure within species;
3. Reproduction and its processes such as flowering, pollination, fruiting, and seed dispersal; and
4. Co₂ gas exchange and dry matter production.

Recent publications:

1. Wang, H., Matsushita, M., Tomaru, N., and Nakagawa, M. (2015) Differences in female reproductive success between female and hermaphrodite individuals in the subdioecious shrub Eurya japonica (Theaceae). Plant Biology: 17: 194-200.
2. Ogawa, K. (2015) Mathematical consideration of the pipe model theory in woody plant species. Trees - Structure and Function 29: 695-704
3. Tokumoto, Y., Sakai, S., Matsushita, M., Ohkubo, T., and Nakagawa, M. (2014) Spatiotemporal variability in the reproductive success of the continually flowering shrub Dillenia suffruticosa in Borneo. Biotropica 46: 583-590.
4. Inanaga, M., Nakanishi, A., Torimaru, T., Nishimura, N., and Tomaru, N. (2014) Distance-dependent but genetically random mating in a Japanese beech (Fagus crenata) population. Botany 92: 795-803.
5. Yoichi, W. and Tomaru, N. (2014) Patterns of geographic distribution have a considerable influence on population genetic structure in one common and two rare species of Rhododendron (Ericaceae). Tree Genetics & Genomes 10: 827-837.
6. Ogawa, K. (2012) Mathematical analysis of age-related changes in leaf biomass in forest stands. Canadian Journal of Forest Research 42: 356-363.

Our research aim is to clarify biotic and abiotic factors responsible for biological phenomena and ecological events in forest ecosystems, which could have various effects upon the health and sustainability of the ecosystems, including biodiversity. Ecology, forest sciences, and evolutional biology are fundamental knowledges in our research fields.

The research projects can be divided into the following major topics:

1. Mechanisms and evolutional processes of the symbiotic interactions between insects and their associated fungi and bacteria (ambrosia and bark beetles, wood wasps, ambrosia gall midges, etc.);
2. Structure and function of arthropod communities in tree canopies and in the soil, with special reference to litter dynamics and community structures of decomposers in relation to the vertical stratification in forests;
3. Spatiotemporal patterns of forest insects and insect-plant interactions (wood-boring insects, seed insects, gall-forming wasps, mycophagous insects, parasitoid wasps, etc.);
4. Conservation of herbaceous and forest ecosystems based on the management of biological communities.

Recent publications:

1. Kobune S, Kajimura H, Masuya H, Kubono T (2011) Symbiotic fungal flora in leaf galls induced by Illiciomyia yukawai (Diptera: Cecidomyiidae) and in its mycangia. Microbial Ecology 63: 619-627.
2. Yoshida T, Hijii N (2011) Microarthropod colonization of litter in arboreal and soil environments of a Japanese cedar (Cryptomeria japonica) plantation. Journal of Forest Research 16: 46-54.
3. Fukumoto H, Kajimura H (2011) Effects of asynchronous acorn production by co-occurring Quercus trees on resource utilization by acorn-feeding insects. Journal of Forest Research 16: 62-67.
4. Ishikawa H (2011) Effects of dung beetles on seedling emergence from herbaceous seeds in the dung of sika deer (Cervus nippon) in a temperate Japanese grassland ecosystem. Ecological Research 26: 725-734.
5. Kawasaki Y, Ito M, Miura K, Kajimura H (2010) Superinfection of five Wolbachia in the alnus ambrosia beetle, Xylosandrus germanus (Blandford) (Coleoptera: Curculiondae). Bulletin of Entomological Research 100: 231-239.
6. Ito M, Kajimura H (2009) Genetic structure of Japanese populations of an ambrosia beetle, Xylosandrus brevis (Curculionidae: Scolytinae). Environmental Entomology 38: 1324-1335.
7. Mizuno T, Kajimura H (2009) Effects of ingredients and structure of semi-artificial diet on the reproduction of an ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Coleoptera: Curculionidae: Scolytinae). Applied Entomology and Zoology 44: 363-370.
8. Karasawa S, Hijii N (2009) Oribatid communities (Acari: Oribatida) associated with bird's nest ferns (Asplenium nidus complex) in a subtropical Japanese forest- a mini-review. Trends in Acarology (MW Sabelis, J Bruin eds): 149-153.

Forests in the world have been decreasing rapidly, followed by serious global warming from greenhouse effect gas (GHG) and impacts on livelihoods of forest-dependent people. In Japan, abandoned forests should be adequately managed and sustained rural villages in the aging population. Our researches investigate sound relationships between global policy issues as climate change/forest conservation and improvement of local livelihoods in tropical countries as Southeast Asia, and development of rural livelihoods ithrough effective use of wood production and biomass resources in Japan

The followings are research topics:

1. Relationships between forests and people in tropical forests, Southeast and South Asian Countries
   -Collaborative forest management in protected areas, especially National Park with governments and local people
   -Certification schemes including forest certification, fair-trade coffee, oil palm plantation (RSPO)
   -Participatory forest management
2. Relationships between forests and people in forests, Japan
   -Working safety and technical training in forest operations
   -Artificial forest management with conserving biodiversity
   -Ergonomic research for sutainable forest managemnt

Selected publications

1. Harada, K., Prabowo, D., Aliadi, A., Ichihara, J. Ma, H.O. (2015) How can social safeguards of REDD⁺ function effectively to conserve forests and improve local livelihoods? A case from Meru Betiri National Park, East Java, Indonesia. Land, 4: 119-139.
2. Yokota, Y., Harada, K., Oktalina, S.N., Rohman, Wiyono, Tanaka, M. and Inoue, M. (2014) Contribution to participant's livelihood by community collaborative forest management system in Java, Indonesia- A case study in Madiun. East Java. Japan Agricultural Research Quarterly, 48(3): 363-377.
3. Harada,K. and Wiyono (2014) Certification of a community- based forest enterprise for improving institutional management and household income: A case from Southeast Sulawesi, Indonesia, Small-scale Forestry, 13(1): 47-64.
4. Harada, K., Rohman, Silvi, N. O., Wiyono (2012) Exploring potentials of forest certification for community-based forest management in Indonesia. Journal of Forest Economics, 58(1): 58-67.
5. Ratsimbazafy, L. C., Harada,K. and Yamamura, M. (2012) Forest resources use, attitude, and perception of local residents towards community based forest management: Case of the Makira Reducing Emissions from Deforestation and Forest Degradation (REDD) Project, Madagascar. Journal of Ecology and the Natural Environment, 4(13): 321-332.
6. Harada, K., Wiyono, Silvi, N. O. and Rohman (2011) Forest certification for community-based forest management as an option for rediscovering community forest in Indonesia. 80-102. The International Conference on Forest Related Traditional Knowledge and Culture in Asia. November 23-26, 2011, Seogwipo, Jeju Islands, Korea Proceeding of International Conference
7. Ratsimbazafy, L. C., Harada,K. and Yamamura, M. (2011) Forest conservaton and livelihood conflict in REDD: A case study from the corridor Ankeniheny Zahamena REDD project, Madagascar. International Journal of Biodiversity and Conservation, 3(12): 618-630.
8. Yozo Yamada, Minoru Kondo, and Kenzo Yogi (2010) Comparative study on physiological burden of a choker man between ground-lead skidding and high-lead Logging -A case study with swing yarder in Miyoshi City, Hiroshima-, Journal of Japan Forest Engineering Society 25(4), 233-2376. (in Japanese)
9. Minoru Kondo and Hiroshi Kobayashi (2006) A study of the statics of H-type skyline systems which two skylines are not parallel and isometry. Journal of Japan Forest Engineering Society 20(4); 219-224. (in Japanese)
10. Minoru Kondo, Sumiko Yamauchi, Takeshi Matsumoto, Yasushi Susuki, and Hiroshi Kobayashi (2005) A study on extraction algorithm of potential yarding area by H-type skyline systems. Journal of Japan Forest Engineering Society 20(3); 193-202. (in Japanese)

Lab. Forest Chemistry conducts organic chemical, biochemical, and analytical chemical researches on the components of woody biomass to clarify its chemical characters, biosynthetic mechanisms, distribution and roles in vivo; and finds new ways to use them, including conversion to functional materials, to realize advanced utilization of forest resources in the recycling-oriented carbon neutral society.

The current research projects are

1. Structures, functions, and formation processes of plant cell walls.
2. 2D/3D visualization of chemical components.
3. Utilization of woody biomass by chemical conversion.

Isolation and structural elucidation, determination of the biosynthesis, and visualization of the distribution of wood extractives.

Recent Publications:

1. Visualization of the distribution of flavonoids in Larix kaempferi wood by fluorescence microscopy, Y. Kawanishi, N. Bito, R. Nakada, T. Imai, Mokuzai Gakkaishi, 61, 297-307 (2015).
2. Isolation and structural elucidation of norlignan polymers from the heartwood of Cryptomeria japonica. Y. Yanase, K. Sakamoto, T. Imai, Holzforschung, 69, 281-296 (2014).
3. Lignification of ray parenchyma cells in the xylem of Pinus densiflora. Part I: Microscopic investigation by POM, UV microscopy, and TOF-SIMS. P. Zheng, D. Aoki, M. Yoshida, Y. Matsushita, T. Imai, K. Fukushima, Holzforschung, 68, 897-905 (2014)
4. The accumulation pattern of ferruginol in the heartwood-forming Cryptomeria japonica xylem as determined by time-of-flight secondary ion mass spectrometry and quantity analysis. K. Kuroda, T. Fujiwara, K.Hashida, T. Imai, M. Kushi, K. Saito, K. Fukushima, Annals of Botany, 113, 1029-1036 (2014).
5. The cryo-TOF-SIMS/SEM system for the analysis of the chemical distribution in freeze-fixed Cryptomeria japonica wood. K. Kuroda, T. Fujiwara, T. Imai, R. Takama, K. Saito, Y. Matsushita, K. Fukushima, Surface and Interface Analysis, 45, 215-219 (2013).
6. Clonal variation in heartwood norlignans of Cryptomeria japonica: evidence for independent control of agatharesinol and sequirin C biosynthesis. N. Bito, R. Nakada, E. Fukatsu, Y. Matsushita, K.Fukushima, T. Imai, Annals of Forest Science, 68, 1049-1056 (2011).
7. In vitro hydroxylation of a norlignan: from agatharesinolto sequirin C and metasequirin C with a microsomal preparation from Cryptomeria japonica. T. Imai, K. Asai, M.Takino, K. Fukushima, Phytochemistry Letters, 2, 196-200 (2009).
8. Heartwood extractives from the Amazonian trees Dipteryx odorata, Hymenaea courbaril, and Astronium lecointei and their antioxidant activities. T. Imai, S. Inoue, N. Ohdaira, R. Suzuki, Y. Matsushita, M. Sakurai, J. M. Henriques, S. K. Ozaki, Z. Finger, K. Fukushima, Journal of Wood Science, 54, 471-475 (2008).
9. Discriminating the indistinguishable sapwood from heartwood in discolored ancient wood by direct molecular mapping of specific extractives using time-of-flight secondary ion mass spectrometry. K. Saito, T. Mitsutani, T. Imai, Y. Matsushita, K. Fukushima, Analytical Chemistry, 80, 1552-1557 (2008).
10. Application of ToF-SIMS to the study on heartwood formation in Cryptomeria japonica trees. K. Kuroda, T. Imai, K. Saito, K. Fukushima, Applied Surface Science, 255, 1143-1147(2008).

The major research objective of BMP is to understand the material properties of wood as well as to clarify the processes of tree growth and cell wall formation, from the physical point of view. Methodology extends over the physical, mechanical, chemical, anatomical and computing methods. Recent our research covers the following topics.
(1): Biomechanics of the living tree: Generation of growth stress and its biological meanings are investigated by means of the field measurement, laboratory analysis, and computing mechanics.
(2) Generation mechanism of the physical properties of wood cell wall: Material testing, electron-microscopic observation, UV-micro-spectrophotometry, X-ray diffraction analysis, molecular biology, as well as theoretical modeling, are employed to make clear the diversity in the physical properties of wood cell wall.
(3) Growth properties and wood qualities of tropical fast-growing species: Wood qualities and maturation properties of tropical fast-growing species are investigated in relation to their rapid lateral growth rate. Our research fields extend over many countries, e.g., Indonesia, Malaysia, Philippine, Brazil, French Guyana, Australia, Argentina, and so forth.

Recent Publications:

1. Kojima, M.; Yamamoto, H.; Yoshida, M.; Ojio,Y.; Okumura, K.: Maturation property of fast-growing hardwood plantation species: A view of fiber length, Forest Ecology and Management, in press (DOI: 10.1016/j.foreco.2008.08.012)
2. Yamashita, S.; Yoshida, M.; Yamamoto, H.; Okuyama, T.: Screening genes that change expression during compression wood formation in Chamaecyparis obtusa, Tree Physiology, 21, 1331-1340, 2008
3. Clair, B.; Gril, J.; Di Renzo, F.; Yamamoto, H.; Quignard, F.: Characterization of a gel in the cell wall to elucidate the paradoxical shrinkage of tension wood, Biomacromolecules, 9, 494-498, 2008
4. Ruelle, J.: Yamamoto, H.: Thibaut, B. : Growth stresses and cellulose structural parameter in tension and normal wood from three tropical rainforest angiosperm species, Bioresources, 2, 235-251, 2007
5. Yamashita, S.; Yoshida, M.; Takayama,S.; Okuyama, T.: Stem-righting mechanism in gymnosperm trees deduced from limitations in compression wood development, Annals of Botany, 99, 487-493, 2007
6. Ruelle, J.: Yoshida, M.; Clair, B.; Thibaut, B.: Peculiar tension wood structure in Laetia procera (Poepp.) Eichl. (Flacourtiaceae), Trees, 21, 345-355, 2007
7. Abe, K.; Yamamoto, H.: The influence of boiling and drying treatments on the behaviors of tension wood with gelatinous layers in Zelkova serrata, Journal of Wood Science, 53,5-10, 2007
8. Nakai, T.; Yamamoto, H.: Properties of the piezoelectric voltage considering the microscopic structure of wood cell walls, Holzforschung, 61, 95-100, 2007

The research target of the laboratory is to establish the effective utilization of timber using physical and engineering methods. The research is developed mainly in the fields of “Timber Engineering” which covers the following three research areas;

(1) Time dependent mechanical behavior of wood and wood-based materials:
The mechanical behavior of wood and wood-based materials in pure and combined stresses are investigated. This research focuses on the influence of the loading states on the strength and deformation in the evaluation of the mechanical characteristics of wood under static and dynamic loading, for example, Poisson’s ratio, fatigue life, and fatigue limit.　The mechanical durability is discussed by energetic and reaction kinetics approaches.

(2) Wood utilization in urban design:
Large-scale inputs of forest resources into urban areas will need to be taken into consideration for the foreseeable future. Urban areas that enjoy the multiple services provided by forests have an obligation to actively promote wood utilization in their design. To help fulfil this obligation, we have launched a research group called “Wood Urban Design Project”. Its purpose is to engage in cross-sectional collaboration toward a fundamental solution to the problems faced by the forestry and timber industries. We discuss the project’s ambit and the problems that may be faced in the effort to revitalize forest and forestry.

(3) Nondestructive inspection for structural safety of historical timber construction:
A method of estimating Young’s modulus of wood-member by measuring only stress wave velocity is newly developed (Japanese patent: 2007-232698). When the method is used, density measurements are not needed. Historical timber construction is inspected with special concern with their structural safety.

Recent Publications:

1. Watanabe, A.; Sasaki, Y.; Yamasaki, M.: Bending Fatigue of Wood: Strain energy-based failure criterion and fatigue life prediction, Wood and Fiber Science, 46(2), 216-227, 2014
2. Nakaya, T.; Yamasaki, M.; Sasaki, Y.: Influence of wall composition on thermal environment of wooden houses, Journal of Wood Science, 60(2), 117-126, 2014
3. Sasaki, Y.; Oya, A.; Yamasaki, M.: Energetic Investigation of the Fatigue of Wood, Holzforschung, 68(7), 843-848, 2014
4. Yamasaki, M.; Uchida, M.; Torichigai, T.; Sasaki, Y.: Strain Measurement and Stress Estimation of Axial Members in the Traditional Wooden Buildings, Journal of Wood Science, 60(6), 403-413, 2014
5. Fukuta, S.; Nomura, M.; Nishizawa, M.; Yamasaki, M.; Sasaki, Y.: Evaluation and fireproofing treatment of wooden heat insulating/acoustic absorbing materials, European Journal of Wood and Wood Products, 72(6), 713-720, 2014
6. Mizutani, M.; Ando, K.: Influence of a wide range of moisture contents on the Poisson's ratio of wood, Journal of Wood Science, 61(1), 81-85, 2015
7. Kawahara, K.; Ando, K.; Taniguchi, Y.: Time dependence of Poisson's effect in wood IV. influence of grain angle, Journal of Wood Science, 61(4), 372-383, 2015
8. Ogawa, K.; Sasaki, Y.; Yamasaki, M.; Fukuta, S.: Theoretical Estimation of Mechanical Properties of Plywood-Sheathed Shear Wall with Combined Use of Adhesive Tape and Wood Dowels, Wood and Fiber Science, 47(4), 421-430, 2015
9. Ogawa, K.; Sasaki, Y.; Yamasaki, M.: Theoretical Modeling and Experimental Study of Japanese "Watari-ago" Joints, Journal of Wood Science, 61(5), 481-491, 2015