Ecosystem Production and Dynamics


Akira OSAWA, Professor
Naoki OKADA, Associate Professor
Masako DANNOURA, Assistant Professor

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Dry matter production, plant community dynamics, and plant ecological and physiological functions that produce observed ecosystem patterns in forests and other major ecosystems have been investigated based primarily on two perspectives.

First is the study of structural dynamics and its mechanisms of forest ecosystems. Tree-ring analysis, mathematical models, and ecological field work are used in combination. Carbon dynamics and carbon accumulation of boreal forests are being estimated in addition to their patterns in the past in northwestern Canada, Finland, Estonia, and Japan. Boreal forests are ecosystems where the effects of global warming are likely to appear early.

Second is the research that analyzes internal structure of stem wood. It examines relationships between size and distribution of water-conducting vessels and leaf opening, shoot extension, or growth rate of trees using the methods of ecological wood anatomy, as well as stable isotopes and tree eco-physiological techniques. Trees in tropical regions, Thailand and Malaysia, are being examined along with those in temperate climates.

Fig.1 : Litter traps installed in a pine forest site in northwestern Canada
Fig.2 : A Tropical seasonal forest with deciduous trees in dry season

Fig.3 : A tree-ring sample for estimating tree growth and past stand structure