Long-term and interdisciplinary research on forest ecosystem functions: challenges at Takayama site since 1993
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- Muraoka, H., Saitoh, T.M. & Nagai, S. Ecol Res (2015) 30: 197. doi:10.1007/s11284-015-1251-9
Forest ecosystems cover approximately 30 % of the terrestrial area of the Earth, and are expected to play crucial roles in regulating our environments including biodiversity and atmospheric CO2 concentration. As the structure and functions of the forest ecosystems are consists of multiple interactions of organisms, soil chemistry and meteorological conditions, which are quite variable in time and space, challenges to understand their processes and resulting dynamics of the functions have been made by various scientific disciplines/techniques such as ecology (including ecophysiology and biogeochemistry), hydrology, micrometeorology, simulation models and remote sensing.
This research has focused particularly on carbon, which is one of the “common” elements of ecological processes involved in ecosystems such as photosynthesis, respiration, and biomass growth, and of the interaction between the atmosphere and ecosystems, as the carbon cycle regulates biological aspects of ecosystems and hence determines the exchange of CO2 between the atmosphere and ecosystems. In recent decades, the carbon cycle and budget have been the central theme of environmental sciences by reflecting the ongoing climate change partly due to the rise in atmospheric CO2. In order to achieve deeper understanding of the dynamics of the structure and functions of forest ecosystems over time and space, it is essential to conduct investigations on (1) the detailed ecological processes in the carbon cycle, (2) their interactions with the climate, (3) integrated analysis of ecological and meteorological process, and (4) observations of such structure and functions over time and space.
As part of the results of our challenging efforts to achieve the multidisciplinary approach and collaborations, we could publish the following articles in this special issue. The reviews provide overview and challenges at the Takayama site by model integration (Ito et al. 2015) and our vision of sensor and site network for phenology observation (Nasahara and Nagai 2015). Ecological studies on carbon cycle of forest ecosystems have been developed by detailed measurements of tree biomass growth and soil carbon dynamics (Kishimoto et al. 2015; Matsushita et al. 2015). Challenges have been also made for revealing soil microbial components in adjacent grasslands (Yoshitake et al. 2015) and to measure the soil structure by MRI (Tomotsune et al. 2015). Leaf and canopy ecophysiological characteristics which are tightly linked with ecosystem productivity in the Takayama site (Noda et al. 2015), atmospheric approach to reveal the temporal changes in carbon exchange between the atmosphere and forests (Ishidoya et al. 2015), and model analyses to clarify the functional contribution of leaf and canopy phenology on forest carbon balance under current and future conditions (Saitoh et al. 2015) or to evaluate the ecosystem services in the regional scale (Ruidisch et al. 2015).
Beside these achievements the research has also been made for soil biogeochemistry with respect to the carbon and nitrogen dynamics, ecophysiological role of tree sapflow and transpiration in forest water cycle, open field warming experiments on tree canopy photosynthesis and soil carbon dynamics, ‘allocation flux’ of carbon beginning from photosynthetic absorption to biomass growth and respiratory fluxes in plants and soil, and the cross-scale consequences of canopy phenology and its functions between stand and landscape scale on the mountainous area. As the integrative efforts by these studies, prediction of future changes in the carbon cycle and resulting budget, and more effective use of satellite remote sensing will be achieved shortly.
We will be grateful if the articles can provide valuable knowledge and information to the colleagues in related research field, and can bridge multiple research disciplines for further networking among the scientists and research sites for future studies.
The Takayama research community appreciates supports gained by the Takayama field station staff (Mr. K. Kurumado and others) of Gifu University and related observation networks. We thank Ecological Research and its editor-in-chief (Dr. A. Kume), an associate editor-in-chief (Dr. T. Kumagai), the secretariat of the editorial office (Ms. Y. Aoshima), many reviewers, and Ecological Society of Japan, for their supports to realize this special issue.