Research/monitoring period: 1997-2001
Research station: Tomakomai Experimental Forest of Hokkaido University (TOEF)
Responsible researchers belong to: Hokkaido University Forests / Graduate School of Environmental Earth Science / Faculty of Agriculture of Hokkaido University
Host university __
Hokkaido University
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Project Funding __ IGBP-MESSC
2nd Term Page
Steady increase of atmospheric carbon-dioxide level is inducing various responses of forest ecosystems through direct and indirect ways. For example, the stand canopy architecture and organic matter storage in soil are predicted to be modified in direct response to increased concentrations of the gas, which will probably influence upon ecological processes of stream/wetland systems, interacting in complex ways with other direct effects. To access the changes in such forest functioning, detailed census is achieved at watershed-scale with various kinds of observation/sampling systems, and with destructive field manipulative experiments. The synthetic approach over hydrology, meteorology, geochemistry, ecology, pedology and limnology in simultaneous monitoring characterizes this project. Goal of the present 5-year project is to construct a functional model for quantitative-prediction of a particular forest ecosystem at the level of watershed landscape.
(1) Monitoring carbon and water flux in forest canopy
In a ridge plateau forest, canopy tower systems with stable electric
supply of 100V DC and a field laboratory system are established in July
1997, and aerodynamic monitoring of CO2
and H2O flux at both canopy-top and trunk-space
boundaries is carried out. Moreover, stable isotope proportion of carbon
and oxygen from air sampled at various height of forest profile is analyzed.
(2) Shift of forest architecture with environmental change
Two mature (each 4 ha) and one riparian secondary (50-yr-old; 10 ha)
forest plots are monitored in tree size dimensions (trunk diameter, tree
height) and litter fall. Using a canopy access system (18-m high, 12-by-12
m wide 'jungle gym') shoot-level physiological and growth processes are
explored, and through modeling the integration of shoot modular units to
a whole tree crown, and, in turn, forest canopy, regulation mechanisms
and response of forest-level architecture to environmental change is simulated.
(3) Carbon flux at forest-stream interface and response of biota
A long-term monitoring system on transportation of dissolved/particulate
carbon and nutrient at forest-stream interface is established in the Horonai
Stream, of which entire watershed is within TOEF. Basic hydrological factors
related to the transportation and storage processes of the organic matter
are simultaneously monitored within the stream. Moreover, temporal changes
in influences of forest-originated organic matter to the biota, including
microbes, benthic invertebrates and fish, are explored to predict indirect
response of the stream ecosystem to changing forest environment. Several
field manipulations, e.g. stream-enclosure experiments removing the organic
matter influx at the interface, are performed to access their contribution
to the stream biota.
Takashi Kohyama
Graduate School of Environmental Earth Science, Hokkaido University,
Sapporo 060, Japan
Fax: +81.11.706.4954; Tel: +81.11.706.2260
Email: kohyama@ees.hokudai.ac.jp
Shigeru Nakano
Tomakomai Experimental Forest, Hokkaido University Forests, Tomakomai
053, Japan
Fax: +81.144.33.2173; Tel: +81.144.33.2171
Email: shige@exfor.agr.hokudai.ac.jp
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____ kohyama@ees.hokudai.ac.jp