Hiroyuki Muraoka

Gifu University | Gidai

Long‐term carbon dioxide (CO2) flux measurements between the atmosphere and the ecosystem have been made since 1993 at a cool‐temperate deciduous forest site (Takayama) in Japan influenced by the Asian Monsoon, constituting the longest data set among all the AsiaFlux sites. Interannual variations (IAVs) and trends in the annual carbon budget compon...

Long-term carbon dioxide (CO) flux measurements between the atmosphere and the ecosystem have been made since 1993 at a cool-temperate deciduous forest site (Takayama) in Japan influenced by Asian Monsoon, constituting the longest dataset among all the AsiaFlux sites. Interannual variations (IAVs) and trends of the annual carbon budget components a...

The rate and extent of global biodiversity change is surpassing our ability to measure, monitor and forecast trends. We propose an interconnected worldwide system of observation networks — a global biodiversity observing system (GBiOS) — to coordinate monitoring worldwide and inform action to reach international biodiversity targets.

As interest in natural capital grows and society increasingly recognizes the value of biodiversity, we must discuss how ecosystem observations to detect changes in biodiversity can be sustained through collaboration across regions and sectors. However, there are many barriers to establishing and sustaining large-scale, fine-resolution ecosystem obs...

Recent advances in satellite-borne optical sensors led to important developments in the monitoring of tropical ecosystems in Asia, which have been strongly affected by recent anthropogenic activities and climate change. Based on our feasibility analyses conducted in Indonesia in Sumatra and Sarawak, Malaysia in Borneo, we discuss the current situat...

Solar-induced chlorophyll fluorescence (SIF) can represent gross primary productivity (GPP) in many types of terrestrial vegetation. In principle, the chlorophyll-a fluorescence signal responds to the amount of light absorption and the fraction of energy distribution in photosystems. Therefore, it is mechanistically linked with CO2 assimilation. Re...

To achieve a sustainable society and solve the problems caused by climate change and socioeconomic activities, it is necessary to monitor the spatial and temporal variability of ecosystem functions, services, and biodiversity at both regional and global scales. During the last decade, we have seen rapid and significant improvement in satellite and...

Photosynthetic carbon assimilation in plant leaves supports biomass accumulation and developmental growth and contributes to the regulation of atmospheric CO2 concentration via the carbon cycle. Photosynthesis and its environmental responses have been the central theme of plant physiological ecology and ecosystem ecology, as photosynthesis is invol...

An improved understanding of the global carbon cycle is important to the success of efforts to mitigate climate change, such as agreed in the Paris meeting of the UN Conference of the Parties in 2016. Climate change mitigation and adaptation requires action by individual countries, municipalities, cities, and their citizens. These actions require a...

Key Message The tree ring weight of Betula ermanii was primarily controlled by the ring width, but not by its ring density. The climate responses of them were clarified by dendrochronological analysis. Abstract Global warming scenarios have made the understanding of carbon sequestration changes in the stems of forest trees important. However, ther...

We present the largest freely available EcoPlate dataset for Japan, comprising data collected from a network of 33 natural forest sites (77 plots) in regions of East Asia ranging from cool temperate to subtropical. EcoPlate is a 96‐well microplate that contains three repeated sets of 31 response wells with different sole carbon substrates. The util...

In this study, we analyzed correlations among the earlywood width (EW) and latewood width (LW) chronologies of Cryptomeria japonica, annual stem biomass increment derived from tree-ring width, climatic factors, and carbon budget of a forest ecosystem [gross primary productivity (GPP), ecosystem respiration (RE) and net ecosystem productivity (NEP)]...

Solar-induced chlorophyll fluorescence (SIF) emissions were estimated by the "area-ratio Fraunhofer line depth (aFLD) method", a new retrieval methodology in spectra from a low spectral resolution (SR) spectroradiometer (MS-700: full width half maximum (FWHM) of 10 nm and spectral sampling interval of 3.3 nm), assisted with a scaling to reference S...

The need for progress in satellite remote sensing of terrestrial ecosystems is intensifying under climate change. Further progress in Earth observations of photosynthetic activity and primary production from local to global scales is fundamental to the analysis of the current status and changes in the photosynthetic productivity of terrestrial ecos...

The Asia-Pacific Biodiversity Observation Network (APBON) was launched in 2009, in response to the establishment of the Biodiversity Observation Network under the Group on Earth Observations in 2008. APBON's mission is to increase exchange of knowledge and know-how between institutions and researchers concerning biodiversity science research in the...

Leaf optical properties (reflectance and transmittance spectra of a single leaf) are the key to interpreting remote sensing data regarding the structure and functions of vegetation canopies. These properties are determined by leaf biochemical and anatomical traits, which change seasonally in deciduous species. To reveal the species-specific seasona...

We investigated the effects of climate factors on tree-ring structure of Cryptomeria japonica in central Japan. We collected cores from 33 plantation trees in the Takayama evergreen coniferous forest site at Gifu University and measured annual ring width (RW), annual mean density (RD), earlywood width (EW), latewood width (LW), earlywood density (E...

Key message Climate responses of radial growth of major hardwood species growing in a cool temperate forest in Japan were clarified by dendrochronological analysis combining the phenology observation of radial growth. Abstract To better understand which climate factors limit the radial growth of major hardwood species growing in a cool temperate f...

Satellite remote sensing (RS) is useful to indirectly evaluate the spatial and temporal variability of land uses, land‐cover changes, aboveground biomass of vegetation, leaf‐area index of terrestrial vegetation canopies, and plant phenology. These observations allow us to gain a deeper understanding of the spatial and temporal variability of ecosys...

Litter and soil organic matter decomposition represents one of the major drivers of carbon and nutrient cycling in a given ecosystem; however, it also contributes to a significant production of relevant greenhouse gasses. The Japanese archipelago spans several biomes (boreal‐temperate‐subtropical) and covers a large range of elevations and ecosyste...

Forest ecosystems play important functional roles over a broad spatial scale in our environment ranging from biodiversity sustainability and ecosystem services at local scales to carbon and water cycles at local, regional and global scales. Micrometeorological observations, ecological research, remote sensing, and simulation models have been used t...

To understand the effects of climate change on radial growth of Japanese beech (Fagus crenata), we developed thirteen ring-width residual chronologies for living trees growing at various sites in Japan. Pearson's correlation coefficients and principal components were calculated for the sites. The chronologies at lower altitudes of Tohoku and Hokkai...

We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network (http://www.pheno-eye.org. Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year-to-year variability in the timing of flowering, leaf-flush, leaf-colo...

Since its founding in 1993 the International Long-term Ecological Research Network (ILTER) has gone through pronounced development phases. The current network comprises 44 active member LTER networks representing 700 LTER Sites and ~ 80 LTSER Platforms across all continents, active in the fields of ecosystem, critical zone and socio-ecological rese...

An accurate estimation of the leaf area index (LAI) by satellite remote sensing is essential for studying the spatial variation of ecosystem structure. The goal of this study was to estimate the spatial variation of LAI over a forested catchment in a mountainous landscape (ca. 60 km2) in central Japan. We used a simple model to estimate LAI using s...

There are growing needs to broaden and deepen our multi-faceted understanding of the ecosystems, and the networks of Long-Term Ecological Research (LTER) can play significant roles in fostering and applying ecosystem studies at regional and global scales. The International LTER Network (ILTER) is organized as a global network of field research site...

The responses of soil respiratory components to global warming are poorly understood particularly in high altitude forest ecosystems. To examine the different responses of soil respiration (RS) components, i.e., autotrophic (RA) and heterotrophic (RH) respirations, in a mountainous temperate forest to elevated temperature, we conducted an open-fiel...

Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO2) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO2. In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ec...

Plant phenology research has gained increasing attention because of the sensitivity of phenology to climate change and its consequences for ecosystem function. Recent technological development has made it possible to gather invaluable data at a variety of spatial and ecological scales. Despite our ability to observe phenological change at multiple...

Light use efficiency (LUE) plays a vital role in determination of crop biomass and yield. Important com- ponents of LUE, i.e. canopy structure, nitrogen distribution, photosynthetic capacity and CO2 diffusion conductance were investigated in paddy rice grown under low, normal and high supplemental nitrogen (0, 115, and 180 kg N h...

Key messageIn the open-field warming experiment using infrared heaters, 3 °C warming affected soil respiration more in the deciduousQuercus variabilisBlume plot than in the evergreenPinus densifloraSieb. et Zucc. plot, but did not affect the plant biomass in either species. ContextUnderstanding the species-specific responses of belowground carbon p...

Net primary production (NPP) refers to the net amount of the carbon and energy fixed by green plants through photosynthetic activity. Estimates of NPP are of fundamental human importance, because food supply is predominantly dependent on plant productivity. Moreover, measurements of spatiotemporal variations of forest NPP provide important informat...

Arctic terrestrial ecosystems are extremely vulnerable to climate change. A major concern is how the carbon balance of these ecosystems will respond to climate change. In this study, we constructed a simple ecological process-based model to assess how the carbon balance will be altered by ongoing climate change in High Arctic tundra ecosystems usin...

EditorialForest 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 meteo...

We studied interannual variations in single-leaf phenology, i.e., temporal changes in leaf ecophysiological parameters that are responsible for forest canopy function, in a cool-temperate deciduous broadleaf forest at Takayama, central Japan. We conducted long-term in situ research from 2003 to 2010 (excluding 2008). We measured leaf mass per unit...

Long-term continuous phenological observation of cherry tree blooming is an important and challenging task in the evaluation of year-to-year weather and climate changes in spring in Japan. Here, (1) we performed daily field observations with a time-lapse digital camera in a deciduous broad-leaved forest in Japan from January 2004 to December 2013;...

Clarification of species-specific year-to-year variations of the timings of the start of leaf-expansion (SLE) and the end of leaf-fall (ELF) is an important and challenging task because these timings may alter spatial and temporal variations in ecosystem services such as carbon stock and climate control. Although many previous studies have applied...

We examined the relationship between the spatio-temporal distribution of leaf litter for each species and the seasonal patterns of in situ and satellite-observed daily vegetation indices in a cool-temperate deciduous broad-leaved forest. The timing and distribution of leaf-fall revealed spatio-temporal relationships with species and topography. Val...

This data paper reports spectral reflectance and transmittance data of leaves from 21 terrestrial vascular plant species (seven herbaceous, and 14 broadleaf and long-needle coniferous tree species) and of shoots from one short-needle coniferous tree species. The reflectance spectra of branches of one tree species, of the trunks of 12 tree species a...

Canopy phenology is a key regulator of carbon cycling in forest ecosystems. To clarify its possible effects on carbon budgets of forest ecosystems under ongoing climate change, we developed a canopy-phenology model for a forest with deciduous overstory and evergreen understory based on in situ observations, and used it to improve an ecosystem carbo...

Forests play an important role in regional and global carbon (C) cycles. With extensive afforestation and reforestation efforts over the last several decades, forests in East Asia have largely expanded, but the dynamics of their C stocks have not been fully assessed. We estimated biomass C stocks of the forests in all five East Asian countries (Chi...

Aims Understanding carbon (C) and nitrogen (N) dynamics and their dependence on the stand density of an even-aged, mature forest provides knowledge that is important for forest management. This study investigated the differences in ecosystem total C and N storage and flux between a low-density stand (LD) and a high-density stand (HD) and examined t...

We estimated the snow water equivalent (SWE) of snowpack in central Japan from September 2006 to August 2008 by using a 3.3 km-mesh regional climate model with two land-surface models: Noah land-surface model (Noah LSM), and Noah land-surface model with multiparameterization options (Noah MP). The model validation for temporal variations of SWE at...

It has been argued that scale is the central problem in ecology (Levin, 1992). Studies on carbon cycles and global climate change, the current major themes in modern ecology, require the interfacing of phenomena that occur on different scales of space, time, and ecological organization. For several decades, tremendous efforts have been made to reve...

Clarification of the year-to-year variations and long-term trends of the timings of the start of leaf-expansion (SLE) and end of leaf-fall (ELF) is an important and challenging task because these timings affect spatial and temporal variations in water, heat and carbon cycles. Here, (1) we examined the relationships between daily mean air temperatur...

Evaluation of the carbon, water, and energy balances in evergreen coniferous forests requires accurate in situ and satellite data regarding their spatio-temporal dynamics. Daily digital camera images can be used to determine the relationships among phenology, gross primary productivity (GPP), and meteorological parameters, and to ground-truth satel...

Temperature affects a cascade of ecological processes and functions of forests. With future higher global temperatures being inevitable it is critical to understand and predict how forest ecosystems and tree species will respond. This paper reviews experimental warming studies in boreal and temperate forests or tree species beyond the direct effect...

Five years (2006–2010) of eddy-covariance data were used to investigate inter-annual variation of evapotranspiration (E) under dry canopy conditions (i.e. no rainfall in the previous 24 h) in summer over a cool-temperate evergreen coniferous forest in Japan. The data included the warmest summer (June to September) in the past 50 years (2010) and th...

Accurate information on the optical properties (reflectance and transmittance spectra) of single leaves is important for an ecophysiological understanding of light use by leaves, radiative transfer models, and remote sensing of terrestrial ecosystems. In general, leaf optical properties are measured with an integrating sphere and a spectroradiomete...

Leaf area index (LAI) is an important parameter in many ecological models and is used to link remote sensing and ecological models. The relationship of LAI and vegetation indices (VIs) such as the normalized difference vegetation index (NDVI) or the enhanced vegetation index (EVI) are not as linear relationship especially for deciduous broadleaf fo...

To estimate global gross primary production (GPP), which is an important parameter for studies of vegetation productivity and the carbon cycle, satellite data are useful. In 2014, the Japan Aerospace Exploration Agency (JAXA) plans to launch the Global Change Observation Mission-Climate (GCOM-C) satellite carrying the second-generation global image...

We examined the relationship between four vegetation indices and tree canopy phenology in an evergreen coniferous forest in Japan based on observations made using a spectral radiometer and a digital camera at a daily time step during a 4 year period. The colour of the canopy surface of Japanese cedar Cryptomeria japonica changed from yellowish-gree...

Aims Understanding of the ecophysiological dynamics of forest canopy photosynthesis and its spatial and temporal scaling is crucial for revealing ecological response to climate change. Combined observations and analyses of plant ecophysiology and optical remote sensing would enable us to achieve these studies. In order to examine the utility of spe...

This REgional Carbon Cycle Assessment and Processes regional study provides a synthesis of the carbon balance of terrestrial ecosystems in East Asia, a region comprised of China, Japan, North and South Korea, and Mongolia. We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990–2009 using three differe...

Recent studies have reported that seasonal variation in camera-based indices that are calculated from the digital numbers of the red, green, and blue bands (RGB_DN) recorded by digital cameras agrees well with the seasonal change in gross primary production (GPP) observed by tower flux measurements. These findings suggest that it may be possible to...

We investigated the relationships between soil respiration and environmental factors during foliation and defoliation periods in three ecosystems under the same physical–geographical environmental conditions in central Japan. These ecosystems comprised deciduous broad-leaved forest (Quercus crispula dominated, site Q), deciduous needle-leaved fores...

Leaf area index (LAI) is a crucial ecological parameter that represents canopy structure and controls many ecosystem functions and processes, but direct measurement and long-term monitoring of LAI are difficult, especially in forests. An indirect method to estimate the seasonal pattern of LAI in a given forest is to measure the attenuation of photo...

Climate change and human activity (land use change and management) are the major drivers of changes in biodiversity, which ranges from the genetic composition of a given population to the structure and functions in an ecosystem and to the ecosystems in a landscape. The structural and functional diversity of an ecosystem on a landscape or regional s...

Biodiversity, the variety of life on Earth, maintains ecosystem services. Since the biodiversity is strongly related to human well-being, the monitoring of biodiversity is significant for global environmental issues. Global Earth Observation System of Systems (GEOSS) is composed of nine Societal Benefit Areas (SBAs), and biodiversity is one of the...

This REgional Carbon Cycle Assessment and Processes regional study provides a synthesis of the carbon balance of terrestrial ecosystems in East Asia, a region comprised of China, Japan, North- and South-Korea, and Mongolia. We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990–2009 using three differ...

We investigated the occurrence of patchy stomatal behavior in leaves of saplings and a forest canopy tree of Quercus crispula Blume. Through a combination of leaf gas-exchange measurements and numerical simulation, we detected patterns of stomatal closure (either uniform or patchy bimodal) coupled with depression of net assimilation rate (A). There...

General, global, long-term, and comprehensive phenological observations are required to evaluate the variability of photosynthetic activities due to environmental changes in terrestrial ecosystems. The observation of seasonal changes and detection of interannual variation in canopy phenology over regional and global scales require satellite data wi...

This study evaluated energy balance closure in the eddy covariance method in a cool-temperate evergreen coniferous forest on steeply sloping topography in a region that experiences snowfall. We investigated the ratio of the sum of sensible and latent heat fluxes to available energy (the energy balance ratio; EBR) and the slope of the regression lin...

The daily total photosynthetically active radiation (400-700 nm, PAR) and near-infrared radiation (700-1000 nm, NIR) were measured in the understory beneath the canopy (PARt and NIRt) and above the canopy (PARi and NIRi) of a Japanese cool-temperate deciduous broad-leaved forest during the snow-free period (May to November). The integration of spec...

Background: Recent studies have described a technique that incorporates a digital camera to observe aspects of tree phenology such as leaf expansion and leaf fall. This technique has shown that seasonal patterns of red, green, and blue digital numbers (RGB_DN) extracted from digital images differ between species.Aims: To identify the different char...

Photosynthetic characteristics and their leaf-age dependence were examined to estimate ecophysiological effects on net primary production (NPP) of a polar willow (Salix polaris), a dominant dwarf shrub species in a polar semi-desert area of Ny-Ålesund, Svalbard. Leaves of S. polaris emerged just after snowmelt in early July in 2000; flowers were in...

In this study, we use three process-based terrestrial ecosystem models (Lund-Potsdam-Jena Dynamic Global Vegetation Model — LPJ-DGVM; ORganizing Carbon and Hydrology In Dynamic Ecosystems – ORCHIDEE; Sheffield model – SDGVM) to investigate the historical response of ecosystem Net Primary Productivity (NPP) and Net Ecosystem Productivity (NEP) over...

We investigated the effect of storage CO 2 flux on evaluating RE( ecosystem respiration), GPP( gross primary production), and NEE( net ecosystem exchange) using 3 years of continuous data by eddy-covariance measurement. In the case of estimating carbon budget without consideration of the storage CO 2 flux, large underestimations in RE and GPP were...

This study evaluated heat storage flux or released flux due to biotic activity (SC) in forests. First, as a case study, we investigated diurnal pattern of SC over an evergreen coniferous forest via a three-year continuous eddy-cov riance CO2 flux measurement. We clarified that (1) in some case, SC reached over 15% of total heat storage flux during...

Measuring light, temperature, soil moisture, and growth provides a better understanding of net ecosystem production (NEP), ecosystem respiration (R eco), and their response functions. Here, we studied the variations in NEP and R eco in a grassland dominated by a perennial warm-season C4 grass, Zoysia japonica. We used the chamber method to measure...

Some previous studies have detected the timing of leaf expansion and defoliation using the normalized-difference vegetation index (NDVI), but to examine tree phenology using satellite data, NDVI results should be confirmed using ground-truthing. We examined the relationship between NDVI and tree phenology during leaf expansion and defoliation by si...

We investigated carbon dioxide (CO2) exchange and its environmental response during two years with contrasting climate (2006 and 2007) in a cool-temperate mixed evergreen coniferous forest dominated by Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa). The study, which was conducted in a mountainous region of central...

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase o...

The pattern of light distribution is a critical input for canopy photosynthesis models. We examined how and to what extent the different calculations of light distribution affect estimations of daily photosynthesis (Aday) of herbaceous vegetation, Sasa senanensis, in a deciduous forest understory. Aday was estimated using three models, the M-S1 (th...

The Moderate Resolution Imaging Spectroradiometer (MODIS) is the primary NASA Earth Observing System instrument monitoring the seasonality of global terrestrial vegetation. MODIS products, such as the MODIS Vegetation Index (VI), Normali zed Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Leaf Area Index (LAI), are commonly...

Revealing the seasonal and interannual variations in forest canopy photosynthesis is a critical issue in understanding the ecological mechanisms underlying the dynamics of carbon dioxide exchange between the atmosphere and deciduous forests. This study examined the effects of temporal variations of canopy leaf area index (LAI) and leaf photosynthet...

Many previous studies have detected the timing of leaf expansion and defoliation using the satellite-observed vegetation indices. However, to examine tree phenology exactly, these results should be confirmed using ground-truthing data. We examined the relationship between vegetation indices (normalized difference vegetation index: NDVI and enhanced...

We examined factors controlling temporal changes in net ecosystem production (NEP) in a high Arctic polar semi-desert ecosystem in the snow-free season. We examined the relationships between NEP and biotic and abiotic factors in a dominant plant community (Salix polaris-moss) in the Norwegian high Arctic. Just after snowmelt in early July, the ecos...

Recent studies have suggested that gross primary production (GPP) of terrestrial vegetation can be estimated directly with the satellite-based Enhanced Vegetation Index (EVI). However, the reported EVI–GPP relationships showed wide variability, with the regression functions showing widely scattered data. In the present study, we examined the possib...