Synergies between observational and modeling studies at the Takayama site: toward a better understanding of processes in terrestrial ecosystems

Abstract

This paper reviews past and ongoing ecological studies at the Takayama forest site, one of Japan's long‐term research sites with intensive studies; the emphasis here is on the synergies between observational and modeling studies. This synergism has been encouraged because global environmental change is a complicated and interdisciplinary issue that requires this type of collaboration. The increasing amount and quality of observational data available from this site helps researchers to better constrain their model simulations because substantial uncertainties remain in the behavior of models in their current form. In addition, modeling studies encourage observational research by integrating observational data within a comprehensive framework. They do this by demanding more long‐term and high‐quality data related to specific ecological processes, and by identifying high‐priority processes and parameters that should be studied. We describe the types of modeling studies that have been conducted and how observational data from the Takayama site have improved the accuracy of these models. Many terrestrial ecosystem models have been applied to data from the site, both to validate the present forms of the models and to refine the structure and parameterization of the models. The development of new or improved terrestrial ecosystem models will be further facilitated by the requirements to simulate atmosphere–ecosystem exchanges and internal biogeochemical processes, as well as simulating their responses to a changing environment. We conclude by discussing the remaining research gaps and opportunities for deepening our understanding of terrestrial ecosystems through future collaborative studies.

Long-term and multidisciplinary research networks on biodiversity and terrestrial ecosystems: findings and insights from Takayama super-site, central Japan

“…In the next section, we illustrate the concept of super-site research at the 'Takayama' site in central Japan, which was launched in 1993 starting with the observations of atmospheric CO 2 concentration and CO 2 flux in a cool-temperate deciduous broadleaf forest ecosystem (Fig. 2) (Ito et al 2015;Muraoka et al 2015;Murayama et al 2003;Yamamoto and Koizumi 2005;Yamamoto et al 1999). Takayama site currently functions as a platform of interdisciplinary science of biodiversity ecosystem research, satellite remote sensing, and model simulations in Earth system science.…”

“…Moreover, climate change is also considered to influence winter weather and snow fall, which impacts photosynthetic activity and disturbance on evergreen coniferous forests (Nagai et al 2018;Saitoh et al 2010). To further investigate the impacts of climate change on forest ecosystems combined studies of in-situ observations and modeling analysis must be continued (Ito et al 2015), and thus gained data and knowledge to be shared with science communities.…”

Plant ecophysiological processes in spectral profiles: perspective from a deciduous broadleaf forest

“…Retrieval of leaf biochemical components (e.g., chlorophyll, nitrogen and water content), LMA and canopy structure parameters (e.g., LAI) from remotely sensed data will enable the ecosystem and Earth system sciences to investigate the diversity of ecosystem functions along climatic gradients and environmental changes from landscape to global scales (Ito et al 2015 ; Rogers et al 2017 ). Inversion of physical model and empirical approach are available to estimate the biochemical and structural parameters of vegetation canopy.…”

Long‐term and interdisciplinary research on forest ecosystem functions: challenges at Takayama site since 1993

“…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). (Muraoka et al 2005) Inter-annual variation of leafphotosynthesis at TKY site Vegetation indices at TKY and TKC sites Camera indices at TKY and TKC sites (Nagai et al 2011;Saitoh et al 2012a) Review (Nasahara & Nagai 2015) Review (Ito et al 2014) Carbon budget at TKY site (Ito et al 2005) Future prediction of carbon budget at TKY site (Ito 2010) Carbon budget at TKC site (Saitoh et al 2012b) Carbon partitioning at grassland, young forest, and TKC sites (Dhital et al 2010;Ohtsuka et al 2010;Yashiro et al 2010) Inter-comparison of carbon budget at TKY site (Ohtsuka et al 2009) Soil respiration at TKC site (Lee et al 2008) Soil respiration at TKY site (Mariko et al 2000) Annual soil respiration at TKY site Carbon partitioning at TKY site (Ohtsuka et al 2005(Ohtsuka et al , 2007 Atmospheric CO 2 at TKY site (Nakazawa et al 1997) Carbon budget at TKY site (Yamamoto et al 1999) Inter-annual variation of carbon budget at TKY site Long-term atmospheric CO 2 and its isotopes at TKY site Carbon budget at TKC site Review of warming experiment (Chung et al 2013) Multi-year analysis of leaf phenology at TKY site (Noda et al 2014) Fig.…”