There remains limited information to characterize the solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationship in C4 cropping systems. The annual C4 crop corn and perennial C4 crop miscanthus differ in phenology, canopy structure and leaf physiology. Investigating the SIF-GPP relationships in these species could deepen our understanding of SIF-GPP relationships within

Perennial crops can improve the ecological and economic sustainability of agroecosystems because of their potential to provide diverse ecosystem services including carbon storage. Intermediate wheatgrass (IWG; Thinopyrum intermedium) is a stress-tolerant grain and forage species that can be grown in bicultures with legumes for symbiotic nitrogen fixation that provide additional ecosystem services but

Intrinsic water-use efficiency (iWUE) is a key physiological trait; however, the spatiotemporal variation in iWUE and which factors affect iWUE in the tropics and subtropics are poorly known. We determined the temporal (1920-2010) and spatial patterns of iWUE using leaf carbon-isotopic composition (δ13C) of 1,811 herbarium specimens and associated these patterns with environmental factors across biomes

The importance of deciduous plants’ autumn phenological phase is reflected not only in the material cycle but also in the fall foliage ecotourism industry. However, the lack of observation data has made it difficult to model the phase of deciduous plants in the high-elevation karst region. Based on the data between 2001 and 2020, methods including multiple linear regression, multivariate binomial regression

The peak photosynthesis timing (PPT) is a key factor that affects the seasonality of the terrestrial carbon uptake. Carbon phenology derived from gross primary production (GPP) has been used to validate the peak greenness timing (PGT) from satellite-based vegetation indices (VIs) in phenology research. However, PPT, derived from GPP, has not been comprehensively analyzed, especially taking different

Changing climate conditions are influencing quality and yield of the United States rice (Oryza sativa L.) export industry. The occurrence of high heat episodes, along with rising atmospheric carbon dioxide (CO2), is of particular concern for as-yet uncharacterized hybrid varieties. A popular rice hybrid was grown in soil-plant-atmosphere-research (SPAR) chambers under two CO2 levels (450 or 740 ppm)

Remote sensing capabilities to monitor evergreen broadleaved vegetation are limited by the low temporal variability in the greenness signal. With canopy greenness computed from digital repeat photography (PhenoCam), we investigated how canopy greenness related to seasonal changes in leaf age and traits as well as variation of trees’ water fluxes (characterized by sap flow and canopy conductance). The

The accurate and timely prediction of crop yield at a large scale is important for food security and the development of agricultural policy. An adaptable and robust method for estimating maize yield for the entire territory of China, however, is currently not available. The inherent trade-off between early estimates of yield and the accuracy of yield prediction also remains a confounding issue. To

Stumps are a key component of managed forest ecosystems, but their role in ecosystem respiration is poorly understood and commonly ignored. Nitrogen (N) addition can affect soil respiration, yet only a few studies have assessed the effect of stumps on soil respiration in intensively managed forests under increasing N deposition. Here, we report the results of a 7-year field experiment to investigate

A more efficient use of limited canopy space and, thus, a higher canopy space occupation (CSO) in forests can result in an increased absorption of photosynthetically active radiation, which in turn can promote productivity. Although there is some evidence for a positive relationship between tree diversity (TD) and CSO, the generality of this hypothesis is still under debate. Here, we propose a conceptual

Eucalypt is one of the most-planted broadleaf genera around the globe, exhibiting high yield, plasticity and growing capacity on a broad range of environments. The main objective of this study is to present the integration of a specific module for eucalypt short-rotation plantations into ECOSMOS (Ecosystem Model Simulator). Different calibrations and validations, from intensively monitored sites, experimental

The frequency and severity of drought are increasing in the context of global warming. Elucidating the responses of crop productivity to drought is essential for informing agricultural management and ensuring food security. Here we used satellite-derived solar-induced chlorophyll fluorescence (SIF) data and vegetation indices to evaluate the impacts of the 2012 drought on crop productivity in the U

Vegetation phenology is highly sensitive to climate change, although the data and methods used to estimate key phenological states can influence this sensitivity. Because of its direct relation to leaf photosynthetic carbon uptake, remotely sensed solar-induced chlorophyll fluorescence (SIF) can provide new insight assessing changes in vegetation phenology. Here, we investigated the potential of using

Using multi-layer pressure fluctuations and other conventional turbulence observational data over a nearly flat and homogeneous dune underlying surface, the temporal and spatial characteristics of pressure flux and its profile were analyzed to illustrate the physical mechanism of pressure flux convergence/divergence and the impact of pressure transport terms on the estimation of turbulent fluxes in

Global warming advances bud break, mismatches plant phenology from the local climate, and exposes the developing leaves to higher risks of frost damage. Bud break of sugar maple [Acer saccharum (Marsh.)], a species included in recent programs of assisted migration, is sensitive to nighttime spring temperatures. This suggests a link between frost events and leaf development. In this study, we raise

In warming climates, soil water content (SWC) may act as an important factor in determining belowground carbon dynamics in boreal forests. Here, we estimated the respiration and nonstructural carbohydrate (NSC) concentrations of tree roots in a mature Scots pine (Pinus sylvestris L.) stand in southern Finland during two growing seasons with contrasting weather conditions. Root respiration was estimated

Drought condition indices (CIs), including single condition (SCIs) and combined condition indices (CCIs), can reveal the characteristics of drought evolution and have been widely used in drought monitoring tasks. However, in practical applications, CIs are constructed in different normalization methods rather than based on a uniform standard. The diversely constructed CIs not only mislead the scientific

In summer 2018, Europe experienced a heatwave that impacted the forest carbon cycle. We assessed the influence of elevated temperatures on the carbon exchange of three forest stands of different types (coniferous, deciduous, and conifer-broadleaved) and a clear-cut area located in the geographical vicinity within a hemiboreal zone. The carbon fluxes were calculated using the eddy-covariance technique

Precise determination of canopy conductance (gs) is needed to quantify the water loss and CO2 exchange from forest canopies and their response to changing environmental conditions. In this study, we combined measurements of the leaf-to-air vapour pressure difference (DL) derived from canopy surface temperature, and tree transpiration to calculate canopy gs in a pine forest at the ICOS site FR-Bil.

Abstract not available

Crop productivity is largely dependent on canopy photosynthesis, which is difficult to measure at farming sites. Therefore, real-time estimation of the canopy photosynthetic rate (Ac) is expected to facilitate effective farm management. For the estimation of Ac, two types of mathematical models (i.e., process-based models and empirical models) have been used, although both types have their own weaknesses

Nitric oxide (NO) is a highly reactive trace gas affecting atmospheric chemistry and air quality. Although forest soils have been recognized as an important source of atmospheric NO, there are large uncertainties in global forest soil NO emission inventories (ranged from 0.03 to 8.00 kg N ha−1, averaged 1.34 ± 0.28 kg N ha−1), partly due to the paucity of high-frequency monitoring from unmanaged forests

Sun-induced chlorophyll fluorescence (SIF) is a direct indicator of plant photosynthetic activities and can potentially indicate plant physiological changes caused by water stress. However, the direct effect of water stress on the physiological SIF responses in crops at the field level still needs further research to clearly understand the involved mechanisms. To study this relationship, we made use

Spring vegetation phenology is highly sensitive to global change. However, the effects of ongoing climate warming and N deposition on grassland spring phenology and how abiotic and biotic factors modulate such effects remain unclear. Here, we conducted a factorial field experiment of warming and N addition in three types of grasslands with varying aridity indices (0.20–0.39) in Inner Mongolia, China

Leaf angle distribution influences forest canopy processes like radiation balance, photosynthesis, and evapotranspiration. Indeed, a strong sensitivity to variability in the leaf angle distribution is reported for many models. Difficulties in conducting leaf angle distribution measurements limit data availability and explanations of its species-specific phenology and variation across environmental

Live Fuel Moisture Content (LFMC) is one of the main factors affecting forest ignitability as it determines the availability of existing live fuel to burn. Currently, LFMC is monitored through spectral vegetation indices or inferred from meteorological drought indices. While useful, neither approach provides mechanistic insights into species-specific LFMC variation and they are limited in the ability

Thermal ecology studies on the ecophysiological responses of organisms to temperature involve two paradigms: physiological rates are driven by body temperature and not directly by the environmental temperature, and they are largely influenced not only by its mean but also its variance. These paradigms together have been largely applied to macro invertebrates and vertebrates but rarely to microorganisms

Urban heat islands (UHI) exacerbates the heat-related risk associated with global warming, increasing morbidity and mortality of urban residents. While the impacts of the spatial pattern of urban greenspace (UG) and its change on urban heat have been widely examined, there is less understanding of the aggregate effect of the change of UG- considering the loss and gain of UG simultaneously - on urban

We aim to identify the importance of vapour pressure deficit (VPD), soil water content (SWC) and photosynthetic photon flux density (PPFD) as drivers of tree canopy conductance, which is a key source of uncertainty for modelling vegetation responses under climate change. We use sap flow time series of 1858 trees in 122 sites from the SAPFLUXNET global database to obtain whole-tree canopy conductance

Incomplete understanding of the processes controlling senescence limits our ability to forecast how the timing of leaf senescence will change in coming decades. In this study, we use a hierarchical Bayesian model (HBM) in association with a 27+ year record of field observations for 12 temperate deciduous tree species collected at Harvard Forest in central Massachusetts to examine how variability in

Plant phenology and growth rate are sensitive bio-indicators of climate change and anthropogenic disturbances. Fire is widespread in many ecosystems worldwide. Understanding how plant growth varies in its response to fire disturbance is critical for fire management. Despite the effects of fire on various aspects of plant ecology, such as the composition and growth of vegetation, little is known about

When applied to plant canopies, classical radiation theory for a turbid medium yields relatively simple expressions for average fluxes of absorbed radiation within an arbitrary volume of vegetation. However, due to the effects of shading and leaf angle, these averaging volumes usually contain a continuous distribution of leaf-level radiative fluxes ranging from full sun to full shade. These distributions

Modeling vegetation phenology is crucial to assessing how climate change impacts carbon cycles in terrestrial ecosystems. The process-based biogeochemical model Biome-BGCMuSo is widely used for simulating carbon and water storages and fluxes of grassland ecosystems. However, the lack of accurate phenological information, such as the start of the growing season (SOS), impedes better simulations of the

Jet streams are a key component of the climate system, whose dynamics couple closely to regional climate variability. Yet, the link between jet stream variability and vegetation activity has received little attention. Here, we leverage our understanding of the mid-latitude jet stream dynamics over the Euro-Atlantic sector to probe climate–vegetation interactions across Europe. We link indices related

Sun-induced chlorophyll fluorescence (SIF) is one of the most promising remote-sensing signals to assess spatio-temporal variation in photosynthesis. Yet, it has been shown that the positive linear relationship of SIF and photosynthesis, often reported from satellite and proximal remote sensing, is mainly driven by the amount of absorbed photosynthetic active radiation (APAR). By normalizing SIF by

Variations in phenology are regarded as a dynamic bio-indicator of global climate change. Rising incomes and the shift toward a diverse diet have been increasing the cash crop demand. However, the response of cash crop phenology to climate change and adaptive management practice remains largely unknown. In this study, using phenology records from 1991 to 2010, we separate the effects of climatic factors

The leaf area index (LAI) is an important indicator reflecting the growth status of vegetation and is widely used in agriculture, ecology, climate change, and other fields. The shortcomings of the currently available methods for manually measuring LAI include labor-intensive, low sampling frequency, and asynchronous data collection. Focusing on these issues, a LAI sensor based on hemispherical photogrammetry

Leaf mass per area (LMA) is an important indicator of plant functioning and photosynthetic capacity and is critical for understanding plant physiology and ecosystem function. Despite detailed and continuous spectral information offered in hyperspectral reflectance, LMA remains a difficult leaf characteristic to be retrieved due to its complex constituents and overlapping absorptions with leaf water

Accurate measurements of leaf temperature and area are crucial to calculate leaf gas exchange parameters when using portable gas analysers such as the LI-6400 XT portable photosynthesis system (LI‐COR Inc., Lincoln, USA). The importance of leaf temperature data is well known for robust measurements, but there are still technical limitations in measuring it with full accuracy. Here we present a tentative

Representing the altitudinal limit of typical vegetation, the alpine timberline is a unique natural landscape that is also a sensitive indicator of the well-being of alpine ecosystems. Schrenk spruce (P. schrenkiana) is a tree species unique to arid Central Asia. In this study, we found that the P. schrenkiana can grow at elevations of up to 3600 m. To better understand how this species survives at

Accurate estimation of chlorophyll content is important for diagnosing the physiological and phenological status of vegetation. Establishing the relationship between vegetation indices (VIs) and leaf chlorophyll content using remote sensing is crucial for large-scale earth observation. However, existing VIs for estimating chlorophyll content generally suffer from the saturation effect or depend on

To study the effects of heat stress in dairy cattle, animal performance records are merged with weather data from nearby meteorological stations. However, the stations location and distribution may render them less reliable. Alternatively, weather information from several meteorological stations can be interpolated using empirical algorithms to produce gridded estimates of weather parameters at desired

The ability of forests to withstand, and recover from, acute drought stress is a critical uncertainty regarding the impacts of climate change on the terrestrial carbon (C) cycle, but it is unclear how drought responses scale from individual trees to whole forests. Here, we assembled a dataset of tree-ring chronologies co-located within the footprint of eddy covariance towers across North America and

The primary focus of this study is to simulate, characterize and validate diurnal patterns of global solar radiation (GSR), temperature, relative humidity and wind speed from daily ground observations from 2017 to 2020 at Obafemi Awolowo University, Ile-Ife, Nigeria. The study also estimates diurnal variations of the meteorological parameters from three daily reanalyses (NASA, NCEP/NCAR and ERA5) and

Observations of the vertical structure of the turbulent flow in different stability regimes above and within the Amazon Forest at the Amazon Tall Tower Observatory (ATTO) site have been presented in Part I. Here, the influence of stability on the inception and development of coherent structures is investigated. According to the mixing-layer analogy the coherent vortices that dominate the turbulent

Understanding the processes that govern the mixing and transport of scalars within and above the Amazon Forest is of great importance for many environmental applications. The impact of atmospheric stability on the roughness sublayer (RSL) as well as the influence on it by the processes in the overlying atmosphere are investigated using measurements collected at the Atmospheric Tall Tower Observatory

Surface soil moisture (SSM) is of great importance in understanding global climate change and studies related to environmental and earth science. However, neither of current SSM products or algorithms can generate SSM with High spatial resolution, High spatio-temporal continuity (cloud-free and daily), and High accuracy simultaneously (i.e., 3H SSM data). Without 3H SSM data, fine-scale environmental

Understanding the impact of land use and land cover change on surface energy and water budgets is increasingly important in the context of climate change research. Eddy covariance (EC) methods are the gold standard for high temporal resolution measurements of water and energy fluxes, but cannot resolve spatial heterogeneity and are limited in scope to the tower footprint (few hundred meter range).

Agricultural land use and management affect land surface albedo and thus the climate. Increasing the albedo of cropland could enhance reflection of solar radiation, counteracting the radiative forcing (RF) of greenhouse gases (GHGs) and local warming. However, knowledge is lacking on how agricultural practices affect albedo under local conditions, and on the benefits of individual practices. In this

Despite the importance of forests in the water and carbon cycles, accurately measuring their contribution remains challenging, especially at night. During clear-sky nights current models and theories fail, as non-turbulent flows and spatial heterogeneity become more important. One of the standing issues is the ‘decoupling’ of the air masses in and above the canopy, where little turbulent exchange takes

Ecological studies have long examined large-scale geographic gradients in abiotic conditions and their relationship to the structure and function of ecological systems, but many critical processes in forested systems are driven by abiotic gradients that vary at fine spatial and temporal scales. To adequately characterize fine scale microclimatic variability, intensive sampling is required that may

Quantifying the ratio of transpiration (T) to evapotranspiration (ET), T/ET, is crucial for understanding and predicting the water cycle and energy balance between the land and atmosphere. Here, we used three well-validated ET partitioning models to estimate T/ET at global fluxnet sites. The models are the Shuttleworth-Wallace-Hu (SWH) model, the Priestley-Taylor Jet Propulsion Lab (PT-JPL) model,

A drought is an extreme moisture deficit event caused by meteorological factors that destroys the structure and function of ecosystems. The recovery time (RT) is a critical metric that describes the responses of ecosystems to drought. However, the factors influencing ecosystem RTs are still unclear at the seasonal scale, especially the influence of the climatic state and the biological processes behind