Graduate School of Agricultural and Life Sciences, The University of Tokyo

Botany for Protecting the Health of Forests and Trees

Various threats to forest ecosystems have been reported worldwide, including forest area reduction due to urbanization and farmland development, isolation and fragmentation of remaining forests, decline and death of trees caused by environmental stresses such as global warming and air pollution, and the spread of invasive diseases associated with globalization. Therefore, the Laboratory of Forest Botany conducts the following research with the aim of maintaining the health of forests and trees.
1) Research on the ecology of plants and microorganisms in forests: In addition to classical community surveys (tree census) and environmental surveys, we study the reproductive modes of plants and fungi using DNA-based parentage analysis techniques and conduct research on the conservation of rare species in suburban forests.
2) Research on the health and stress responses of individual trees: We have developed the world’s only MRI system for trees to study their responses to drought stress and infections.
3) Research on interactions between trees and microorganisms (saprophytism, parasitism and symbiosis): We study tree pests and diseases such as pine wilt and oak wilt, decay damage in street trees that causes them to fall, and mycorrhizal fungi such as matsutake that symbiotically associate with tree roots.

Understanding the Diversity and Functions of Organisms in Forests and Trees

Through omnibus lectures for Komaba students such as “Ecology of Forest Organisms” and omnibus courses common to the Faculty of Agriculture such as “Diversity and Evolution of Life,” we introduce trees and fungi. As specialized subjects for the Forest Biological Sciences and Forest Environmental Sciences courses, we offer classes covering basics to applications on the physiology and ecology of plants and fungi inhabiting forests, including “Forest Botany,” “Dendrology,” “Forest Ecology,” and “Tree Pathology.” At the graduate level, courses include “Advanced Forest Botany,” “Tree Physiology,” “Environmental Botany,” “Advanced Forest Ecology,” and “Forest Pathology.”
Students in the Forest Biological Sciences and Forest Environmental Sciences majors learn about the major tree species of Japan and the ecology of plants, animals, and microorganisms living in forests through indoor experiments such as “Basic Training for Forest Science Basics” and “Experiments in Forest Life Science” as well as field training at experimental forests conducted jointly with other laboratories.
Our laboratory aims to train researchers involved in the health of forests and trees, public officials and greening engineers engaged in forest conservation and urban tree management, while also providing students in Komaba and Faculty of Agriculture who will play active roles in various fields of society with fundamental knowledge and cutting-edge issues related to “green,” through lectures and practical training, hoping they will become human resources who contribute to the development of a society in harmony with nature.

Seeking New Technologies to Enable Physiological Diagnosis of Trees

We conduct researches on tree physiology and pathology using diverse methods such as measuring physiological states at the individual and leaf levels through photosynthesis-transpiration measurements and chlorophyll fluorescence; observing internal trunk responses with non-destructive observation techniques like MRI and micro X-ray CT; cryo-SEM for observing frozen water in xylem vessels; and histochemical staining for examining cellular-level responses. We are developing various research methods to elucidate the physiological state of trees and the mechanisms of tree diseases, and we welcome collaboration with companies possessing relevant technologies.
Through joint research with the University of Tsukuba and MR Technology Co., Ltd., we have developed MRI for trees and applied it to studies on tree water physiology. To clarify water transport in trees, high-resolution micro X-ray CT is useful for non-destructive observation of internal trunks. However, tree seedlings typically have a height of about one meter despite their small trunk diameter, preventing them from fitting into standard high-resolution CT chambers. The development of high-resolution CT systems with vertically elongated large chambers is awaited. Furthermore, diagnostic methods for assessing the risk of street trees and diagnosing diseases in wild trees—non-destructively observing the internal trunks and underground root systems of tall trees—are also fields with significant social needs and potential for technological development.