scholarly journals Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part I evaluation of a water and carbon balance model

2015 ◽  
Vol 353 ◽  
pp. 260-268 ◽  
Author(s):  
Shanlei Sun ◽  
Ge Sun ◽  
Peter Caldwell ◽  
Steven G. McNulty ◽  
Erika Cohen ◽  
...  
Keyword(s):  
Carbon Balance ◽  
Ecosystem Functions ◽  
Balance Model ◽  
National Forests ◽  
Drought Impacts ◽  
The U.S

Soil organic carbon sequestration potential for Canadian Agricultural Ecoregions calculated using the Introductory Carbon Balance Model

2008 ◽  
Vol 88 (4) ◽  
pp. 451-460 ◽  
Author(s):  
M A Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
L -E Parent
Keyword(s):  
Biological Activity ◽  
Carbon Balance ◽  
Crop Production ◽  
Field Experiments ◽  
Balance Model ◽  
Agricultural Crop ◽  
Organic C ◽  
Soil Biological Activity ◽  
Sequestration Potential

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_crop value of 0.95 for western ecoregions was on average 0.23 units lower than that of the eastern ecoregions, indicating a lower decomposition rate of SOC. Although the estimated annual C inputs to soil for small-grain cereals were on average ≈7.5% higher in the eastern ecoregions (305 vs. 285 g C m-2 yr-1), the overall results suggest that the western ecoregions would have a greater potential to maintain high SOC levels in the long term. However, these parameters varied between ecoregions and, consequently, the SOC sequestration potential was not always higher for the western ecoregions. The effect of fallow was on average ≈0.04, i.e., SOC decomposed slightly faster under fallow. Predictions for 24 out of 33 site and treatment combinations across Canada were significantly improved (P = 0.003), compared with a previous application with the ICBM that did not differentiate between crops and fallow. The methodology used here enabled us to examine regional differences in the potential for SOC sequestration as a balance between annual C inputs to soil and soil biological activity. Key words: Annual C inputs, climate, fallow, soil biological activity, agroecosystems

scholarly journals Quantifying the effect of nitrogen-induced physiological and structural changes on poplar growth using a carbon-balance model

2011 ◽  
Vol 31 (4) ◽  
pp. 381-390 ◽  
Author(s):  
L. Coll ◽  
R. Schneider ◽  
F. Berninger ◽  
S. Domenicano ◽  
C. Messier
Keyword(s):  
Carbon Balance ◽  
Structural Changes ◽  
Balance Model ◽  
Poplar Growth

scholarly journals Bayesian calibration of a carbon balance model PREBAS using data from permanent growth experiments and national forest inventory

2019 ◽  
Vol 440 ◽  
pp. 208-257 ◽  
Author(s):  
Francesco Minunno ◽  
Mikko Peltoniemi ◽  
Sanna Härkönen ◽  
Tuomo Kalliokoski ◽  
Harri Makinen ◽  
...  
Keyword(s):  
Forest Inventory ◽  
Carbon Balance ◽  
National Forest Inventory ◽  
Balance Model ◽  
National Forest ◽  
Bayesian Calibration ◽  
Using Data ◽  
Growth Experiments

scholarly journals Drought impacts on tree phloem: from cell-level responses to ecological significance

2019 ◽  
Vol 39 (2) ◽  
pp. 173-191 ◽  
Author(s):  
Yann Salmon ◽  
Lars Dietrich ◽  
Sanna Sevanto ◽  
Teemu Hölttä ◽  
Masako Dannoura ◽  
...  
Keyword(s):  
Tree Mortality ◽  
Phloem Transport ◽  
Water Shortage ◽  
Cellular Level ◽  
Ecosystem Functions ◽  
Future Research ◽  
Severe Drought ◽  
Long Distance ◽  
Drought Impacts ◽  
Tree Survival

Abstract On-going climate change is increasing the risk of drought stress across large areas worldwide. Such drought events decrease ecosystem productivity and have been increasingly linked to tree mortality. Understanding how trees respond to water shortage is key to predicting the future of ecosystem functions. Phloem is at the core of the tree functions, moving resources such as non-structural carbohydrates, nutrients, and defence and information molecules across the whole plant. Phloem function and ability to transport resources is tightly controlled by the balance of carbon and water fluxes within the tree. As such, drought is expected to impact phloem function by decreasing the amount of available water and new photoassimilates. Yet, the effect of drought on the phloem has received surprisingly little attention in the last decades. Here we review existing knowledge on drought impacts on phloem transport from loading and unloading processes at cellular level to possible effects on long-distance transport and consequences to ecosystems via ecophysiological feedbacks. We also point to new research frontiers that need to be explored to improve our understanding of phloem function under drought. In particular, we show how phloem transport is affected differently by increasing drought intensity, from no response to a slowdown, and explore how severe drought might actually disrupt the phloem transport enough to threaten tree survival. Because transport of resources affects other organisms interacting with the tree, we also review the ecological consequences of phloem response to drought and especially predatory, mutualistic and competitive relations. Finally, as phloem is the main path for carbon from sources to sink, we show how drought can affect biogeochemical cycles through changes in phloem transport. Overall, existing knowledge is consistent with the hypotheses that phloem response to drought matters for understanding tree and ecosystem function. However, future research on a large range of species and ecosystems is urgently needed to gain a comprehensive understanding of the question.

Roads on the U.S. National Forests

1999 ◽  
Vol 31 (4) ◽  
pp. 514-539 ◽  
Author(s):  
David N. Bengston ◽  
David P. Fan
Keyword(s):  
National Forests ◽  
The U.S

scholarly journals Climate data induced uncertainties in simulated carbon fluxes under corn and soybean systems

2020 ◽  
Author(s):  
Varaprasad Bandaru
Keyword(s):  
Carbon Flux ◽  
Carbon Balance ◽  
Management Practices ◽  
Irrigation Management ◽  
Carbon Fluxes ◽  
Climate Data ◽  
Weather Variables ◽  
Relative Significance ◽  
Daily Weather ◽  
The U.S

Abstract. Net carbon balance on croplands depends on numerous factors (e.g., crop type, soil, climate and management practices) and their interactions. Agroecosystem models are generally used to assess cropland carbon fluxes under various agricultural land use and land management practices because of their ability to capture the complex interactive effects of factors influencing carbon balance. For regional carbon flux simulations, generally gridded climate data sets are used because they offer data for each grid cell of the region of interest. However, studies consistently report large uncertainties in gridded climate datasets, which will affect the accuracy of carbon flux simulations. This study investigates the uncertainties in daily weather variables of commonly used high resolution gridded climate datasets in the U.S (NARR, NLDAS, Prism and Daymet), and their impact on the accuracy of simulated Net Ecosystem Exchange (NEE) under irrigated and non-irrigated corn and soybeans using the Environmental Policy Integrated Climate (EPIC) agroecosystem model and observational data at four flux tower cropland sites in the U.S Midwest region. Further, the relative significance of each weather variable in influencing the uncertainty in flux estimates was evaluated. Results suggest that daily weather variables in all gridded climate datasets display some degree of bias, leading to considerable uncertainty in simulated NEE fluxes. The gridded climate datasets produced based on interpolation techniques (i.e. Daymet and Prism) were shown to have less uncertainties, and resulted in NEE estimates with relatively higher accuracy, likely due to their higher spatial resolution and higher dependency on meteorological station observations. The Mean Absolute Percentage Errors (MAPE) values of average growing season NEE estimates for Dayment, Prism, NLDAS and NARR include 22.53 %, 23.45 %, 62.52 % and 66.18 %, respectively. The NEE under irrigation management (MAPE = 53.15 %) tends to be more sensitive to uncertainties compared to the fluxes under non-irrigation (MAPE = 34.19 %). Further, this study highlights that NEE fluxes respond differently to the individual climate variables, and responses vary with management practices. Under irrigation management, NEE fluxes are more sensitive to shortwave radiation and temperature. Conversely, under non-irrigation management, precipitation is the most dominant climate factor influencing uncertainty in simulated NEE fluxes. These findings demonstrate that careful consideration is necessary when selecting climate data to mitigate uncertainties in simulated NEE fluxes. Further, alternative approaches such as integration of remote sensing data products may help reduce the models' dependency on climate datasets and improve the accuracy in the simulated CO2 fluxes.

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