Laboratory of Forest Ecology

We conduct various studies to achieve sustainable forest management and forest conservation with "an ecosystem approach." We are part of the Graduate School of Agriculture, Kyoto University, and invite applicants to undertake a graduate course for M.Sc. and D.Sc. widely from Japan and foreign countries. We also provide undergraduate students with basic education as part of the School of Agriculture. Graduate students can conduct doctoral or master research in English. “Ecosystem approach” focuses the following three principles: a long-term scale to secure the tree regeneration of multiple generations and to allow the feedback processes between trees and environments, a wide spatial scale to allow matter transfers among ecosystems, and the ecosystem functions of biological diversity. We study the ecosystem functions of biological diversity which are essential to materialize the long-term sustainability of forest ecosystems on an ecological time/spatial scale. Particularly, we focus the nutrient dynamics and the structure and function of biological communities in forest ecosystems. Undergraduate and graduate students, post-doctoral researchers, and faculties in our laboratory study various topics in a friendly atmosphere (Research Activities). We also conduct interdisciplinary projects which consist of many researchers (Projects). Our laboratory is designated as one of the Center of Excellence for promoting academic exchange programs in Asia and Africa by JSPS (Japan Society for Promotion of Sciences) and extends collaborative research programs and international seminars with foreign partner institutes (JSPS Program).

Research Activities

We focus "ecosystem physiology," "community structure and functions of trees and insects," and "sustainable management of forest ecosystems."

We study a wide range of forest types from pristine forests, plantation forests and secondary forests. Pristine forests include gigantic tropical rain forests in Borneo and a beech forest in the university's educational forest located in northern Kyoto. Forest ecosystems are indeed very diverse as their structure and functions vary with physical environments (climate and soils) and with the magnitude of human interference. However, there must be some commonalities across various forest types because all forests consist of the populations of tall trees. We study fundamental ecosystem processes pertinent to the long-term maintenance of forest ecosystems.
-Dilemma of a forest-
In the long evolutionary process, trees have extended their heights for the competition for light. Lignified tissues and organs of trees gave mechanical strength for achieving taller stature and eventually a massive forest structure. On the other hand, the resistance for hydraulic conductance increased as tree became taller. Nutrient recycling from litter became retarded as tissues became increasingly lignified. Furthermore, the diffusion rate of CO2 through lignified foliar tissues became a factor to reduce the photosynthetic rate. Consequently, all tall trees which form a forest ecosystem may suffer from a "dilemma" of being tall while maintaining productivity with a sustained rate of photosynthesis and nutrient recycling.

-Ecosystem physiology-
Trees have developed various adaptive mechanisms for maintaining productivity as well as structure. Diverse organisms such as soil fauna and microbes are also intimately related to the long-term maintenance of forest ecosystems. Without such mechanisms and biological diversity, forests would rapidly decline. We take an ecosystem physiology approach and investigate the adaptive mechanisms of long-term maintenance of forest ecosystems by merging plant physiology, biogeochemistry and biodiversity science. Especially, we are interested in the deficiency of soil phosphorus and ecosystem-level adaptation. We are also interested in the role of soil fauna and microbes in ecosystem processes.

/Example of research

  • Phosphorus deficiency, and the P-use efficiency and adaptation of tropical rain forest trees
  • Soil phosphorus dynamics
  • Ecosystem ecology of polyphenols
  • Water-use and nutrient-use efficiencies of tree leaves
  • Acclimation to light environments through the adjustment of module structure
  • The dynamics of tree roots and adaptations

-Community structure and functions of trees and insects-
A forest ecosystem consists of myriads of organisms. Especially, an equatorial tropical rain forest consists of more than 200 species within 1 ha. Inter-specific competition would drive out subordinate species and eventually a few dominant species would remain. Why do so many species co-exist within one forest despite competition? This has been a challenging research question for many ecologists. We study this research question from our own unique stand point. For instance, we study the niche differentiation among several co-existing tree species by investigating the specific differences in drought avoidance, water-use, nutrient-use, and nutrient acquisition in a Bornean tropical rain forest. We also study localized occurrence of soil microbial communities and the formation of patch units in soil-nutrient availability, which may give rise to the niche differentiation among tree species.

/Example of research

  • Habitat associations among co-existing tree species
  • Water potential of tree species and niche differentiation
  • Soil microbial communities and soil-nutrient dynamics

-Sustainable management of forest ecosystems-
Forests have been heavily used as wood as well as non-wood resources by human beings in her long history. The majority of the forests are now highly degraded. On the other hand, forests are expected to continue providing various ecosystem services for human beings. Under the increasing threats of global warming, the sustainable use of forests is inevitable to sustain healthy human societies. We study the sustainable use of forests with an ecosystem approach. "Sustainability" must be assured with a minimal feedback on a longer time scale on a wider spatial scale. A special attention must be paid to the maintenance of biological diversity because the diversity has essential roles in ecosystem functions. We conduct a research project to jointly achieve timber production, carbon sequestration and biological conservation in a Bornean tropical rain forest in Deramakot, Sabah, Malaysia, with close collaboration with Sabah State Government (Link to Deramakot Project).

/Example of research

  • Relationships of harvest intensity and long-term carbon dynamics in tropical rain forests
  • Harvest intensity and soil organic carbon
  • Developing monitoring methods of and indicators of biological diversity for sustainable forest management
  • Developing the monitoring methods of mammalian diversity and their conservation
  • The application of satellite remote sensing in the sustainable forest management