scholarly journals China's terrestrial carbon balance: Contributions from multiple global change factors

2011 ◽  
Vol 25 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hanqin Tian ◽  
Jerry Melillo ◽  
Chaoqun Lu ◽  
David Kicklighter ◽  
Mingliang Liu ◽  
...  
Keyword(s):  
Global Change ◽  
Carbon Balance ◽  
Terrestrial Carbon ◽  
Change Factors

Exploring the effects of biodiversity and elemental stoichiometry on terrestrial carbon balance

2020 ◽  
Author(s):  
Marcos Fernández-Martínez ◽  
Jordi Sardans ◽  
Josep Peñuelas ◽  
Ivan Janssens
Keyword(s):  
Global Change ◽  
Elemental Composition ◽  
Carbon Balance ◽  
Terrestrial Ecosystems ◽  
Terrestrial Carbon ◽  
Endogenous Factors ◽  
Ecosystem Carbon ◽  
Elemental Stoichiometry ◽  
Ecosystem Carbon Balance

<p>Global change is affecting the capacity of terrestrial ecosystems to sequester carbon. While the effect of climate on ecosystem carbon balance has largely been explored, the role of other potentially important factors that may shift with global change, such as biodiversity and the concentration of nutrients remains elusive. More diverse ecosystems have been shown to be more productive and stable over time and differences in foliar concentrations of N and P are related to large differences in how primary producers function. Here, we used 89 eddy-covariance sites included in the FLUXNET 2015 database, from which we compiled information on climate, species abundance and elemental composition of the main species. With these data, we assessed the relative importance of climate, endogenous factors, biodiversity and community-weighted concentrations of foliar N and P on terrestrial carbon balance. Climate and endogenous factors, such as stand age, are the main determinants of terrestrial C balance and their interannual variability in all types of ecosystems. Elemental stoichiometry, though, played a significant role affecting photosynthesis, an effect that propagates through ecosystem respiration and carbon sequestration. Biodiversity, instead, had a very limited effect on terrestrial carbon balance. We found increased respiration rates and more stable gross primary production with increasing diversity. Our results are the first attempt to investigate the role of biodiversity and the elemental composition of terrestrial ecosystems in ecosystem carbon balance.</p>

scholarly journals Century‐scale patterns and trends of global pyrogenic carbon emissions and fire influences on terrestrial carbon balance

2015 ◽  
Vol 29 (9) ◽  
pp. 1549-1566 ◽  
Author(s):  
Jia Yang ◽  
Hanqin Tian ◽  
Bo Tao ◽  
Wei Ren ◽  
Chaoqun Lu ◽  
...  
Keyword(s):  
Carbon Emissions ◽  
Carbon Balance ◽  
Terrestrial Carbon ◽  
Pyrogenic Carbon

scholarly journals Non-structural carbohydrate concentrations in woody organs, but not leaves, of temperate and tropical tree angiosperms are independent of the ‘fast-slow’ plant economic spectrum

2021 ◽  
Author(s):  
J.A. Ramirez ◽  
D. Craven ◽  
J.M. Posada ◽  
B. Reu ◽  
C.A. Sierra ◽  
...  
Keyword(s):  
Global Change ◽  
Functional Traits ◽  
Carbon Allocation ◽  
Plant Traits ◽  
Vital Role ◽  
Change Factors ◽  
Leaf Habit ◽  
As Species ◽  
Structural Carbohydrate ◽  
The Relationship

SummaryBackground and AimsCarbohydrate reserves play a vital role in plant survival during periods of negative carbon balance. Considering active storage of reserves, there is a trade-off between carbon allocation to growth and to reserves and defense. A resulting hypothesis is that allocation to reserves exhibits a coordinated variation with functional traits associated with the ‘fast-slow’ plant economics spectrum.MethodsWe tested the relationship between non-structural carbohydrates (NSC) of tree organs and functional traits using 61 angiosperm tree species from temperate and tropical forests with phylogenetic hierarchical Bayesian models.Key ResultsOur results provide evidence that NSC concentrations in woody organs and plant functional traits are largely decoupled, meaning that species’ resilience is unrelated to their position on the ‘fast-slow’ plant economics spectrum. In contrast, we found that variation between NSC concentrations in leaves and the fast-slow continuum was coordinated, as species with higher leaf NSC had traits values associated with resource conservative species such as lower SLA, lower Amax, and high wood density. We did not detect an influence of leaf habit on the variation of NSC concentrations in tree organs.ConclusionsEfforts to predict the response of ecosystems to global change will need to integrate a suite of plant traits, such as NSC concentrations in woody organs, that are independent of the ‘fast-slow’ spectrum and that capture how species respond to a broad range of global change factors.

A synthesis of soil nematode responses to global change factors

2021 ◽  
pp. 108538
Author(s):  
Juan Zhou ◽  
Jianping Wu ◽  
Jingxing Huang ◽  
Xiongjie Sheng ◽  
Xiaolin Dou ◽  
...  
Keyword(s):  
Global Change ◽  
Soil Nematode ◽  
Change Factors

Does forest growth acceleration lead to denser stands? Insights from Swiss forests and mechanistic modelling

2021 ◽  
Author(s):  
Laura Marques ◽  
Ensheng Weng ◽  
Harald Bugmann ◽  
David I. Forrester ◽  
Martina Hobi ◽  
...  
Keyword(s):  
Tree Growth ◽  
Carbon Balance ◽  
Tree Mortality ◽  
Forest Growth ◽  
Growth Enhancement ◽  
Carbon Sinks ◽  
Terrestrial Carbon ◽  
Model Simulations ◽  
Leaf Level ◽  
Use Efficiency

<p>Forest demographic processes - growth, recruitment and mortality - are being altered by global change. The changing balance between growth and mortality strongly influences forest dynamics and the carbon balance. Elevated atmospheric carbon dioxide (eCO<sub>2</sub>) has been reported to enhance photosynthesis and tree growth rates by increasing both light-use efficiency (LUE) and water-use efficiency (WUE). Tree growth enhancement could be translated into an increase in biomass stocks or could be associated with a reduction in the longevity of trees, thus reducing the ability of forest ecosystems to act as carbon sinks over long timescales. These links between growth and mortality, and the implications for forest stand density and self-thinning relationships are still debated. Scarce empirical evidence exists for how changing drivers affect tree mortality due to existing data and modelling limitations. Understanding the causes of observed mortality trends and the mechanisms underlying these processes is critical for accurate projections of global terrestrial carbon storage and its feedbacks to anthropogenic climate change.</p><p>Here, we combine a mechanistic model with empirical forest data to better understand the causes of changes in tree mortality and the implications for past and future trends in forest tree density. Specifically, we test the Grow-Fast-Die-Young hypothesis to investigate if a leaf-level CO<sub>2</sub> fertilization effect may lead to an increase in the biomass stock in forest stands. We use a novel vegetation demography model (LM3-PPA) which includes vegetation dynamics with biogeochemical processes allowing for explicit representation of individuals and a mechanistic treatment of tree mortality. The key links between leaf-level assimilation and stand dynamics depend on the carbon turnover time. In this sense, we investigate alternative mortality assumptions about the functional dependence of mortality on tree size, tree carbon balance or growth rate. These formulations represent typical approaches to simulate mortality in mechanistic forest models. Model simulations show that increasing photosynthetic LUE leads to higher biomass stocks, with contrasting behavior among mortality assumptions. Empirical data from Swiss forest inventories support the results from the model simulations showing a shift upwards in the self-thinning relationships, with denser stands and bigger trees. This data-supported mortality-modelling helps to identify links between forest responses and environmental changes at the leaf, tree and stand levels and yields new insight into the causes of currently observed terrestrial carbon sinks and future responses.</p>

scholarly journals Multifactor controls on terrestrial N<sub>2</sub>O flux over North America from 1979 through 2010

2012 ◽  
Vol 9 (4) ◽  
pp. 1351-1366 ◽  
Author(s):  
X. F. Xu ◽  
H. Q. Tian ◽  
G. S. Chen ◽  
M. L. Liu ◽  
W. Ren ◽  
...  
Keyword(s):  
North America ◽  
Global Change ◽  
Climate Variability ◽  
Fertilizer Application ◽  
N2o Emission ◽  
N Deposition ◽  
N Fertilizer ◽  
Multiple Factors ◽  
Change Factors ◽  
Factor Interaction

Abstract. Nitrous oxide (N2O) is a potent greenhouse gas which also contributes to the depletion of stratospheric ozone (O3). However, the magnitude and underlying mechanisms for the spatiotemporal variations in the terrestrial sources of N2O are still far from certain. Using a process-based ecosystem model (DLEM – the Dynamic Land Ecosystem Model) driven by multiple global change factors, including climate variability, nitrogen (N) deposition, rising atmospheric carbon dioxide (CO2), tropospheric O3 pollution, N fertilizer application, and land conversion, this study examined the spatial and temporal variations in terrestrial N2O flux over North America and further attributed these variations to various driving factors. From 1979 to 2010, the North America cumulatively emitted 53.9 ± 0.9 Tg N2O-N (1 Tg = 1012 g), of which global change factors contributed 2.4 ± 0.9 Tg N2O-N, and baseline emission contributed 51.5 ± 0.6 Tg N2O-N. Climate variability, N deposition, O3 pollution, N fertilizer application, and land conversion increased N2O emission while the elevated atmospheric CO2 posed opposite effect at continental level; the interactive effect among multiple factors enhanced N2O emission over the past 32 yr. N input, including N fertilizer application in cropland and N deposition, and multi-factor interaction dominated the increases in N2O emission at continental level. At country level, N fertilizer application and multi-factor interaction made large contribution to N2O emission increase in the United States of America (USA). The climate variability dominated the increase in N2O emission from Canada. N inputs and multiple factors interaction made large contribution to the increases in N2O emission from Mexico. Central and southeastern parts of the North America – including central Canada, central USA, southeastern USA, and all of Mexico – experienced increases in N2O emission from 1979 to 2010. The fact that climate variability and multi-factor interaction largely controlled the inter-annual variations in terrestrial N2O emission at both continental and country levels indicate that projected changes in the global climate system may substantially alter the regime of N2O emission from terrestrial ecosystems during the 21st century. Our study also showed that the interactive effect among global change factors may significantly affect N2O flux, and more field experiments involving multiple factors are urgently needed.

scholarly journals Interactive global change factors mitigate soil aggregation and carbon change in a semi‐arid grassland

2020 ◽  
Vol 26 (9) ◽  
pp. 5320-5332 ◽  
Author(s):  
Tongshuo Bai ◽  
Peng Wang ◽  
Steven J. Hall ◽  
Fuwei Wang ◽  
Chenglong Ye ◽  
...  
Keyword(s):  
Global Change ◽  
Soil Aggregation ◽  
Change Factors ◽  
Carbon Change ◽  
Semi Arid

scholarly journals Evaluation of Biases in JRA-25/JCDAS Precipitation and Their Impact on the Global Terrestrial Carbon Balance

2011 ◽  
Vol 24 (15) ◽  
pp. 4109-4125 ◽  
Author(s):  
Makoto Saito ◽  
Akihiko Ito ◽  
Shamil Maksyutov
Keyword(s):  
Carbon Cycle ◽  
Carbon Balance ◽  
Regional Scale ◽  
Precipitation Amount ◽  
Temporal Variations ◽  
Japan Meteorological Agency ◽  
Total Biomass ◽  
Monthly Precipitation ◽  
Precipitation Data ◽  
Terrestrial Carbon

Abstract This study evaluates a modeled precipitation field and examines how its bias affects the modeling of the regional and global terrestrial carbon cycle. Spatial and temporal variations in precipitation produced by the Japanese 25-yr reanalysis (JRA-25)/Japan Meteorological Agency (JMA) Climate Data Assimilation System (JCDAS) were compared with two large-scale observation datasets. JRA-25/JCDAS captures the major distribution patterns of annual precipitation and the features of the seasonal cycle. Notable problems include over- and undersimulated areas of precipitation amount in South America, Africa, and Southeast Asia in the 30°N–30°S domain and a large discrepancy in the number of rainfall days. The latter problem was corrected by using a stochastic model based on the probability of the occurrence of dry and wet day series; the monthly precipitation amount was then scaled by the comparison data. Overall, the corrected precipitation performed well in reproducing the spatial distribution of and temporal variations in total precipitation. Both the corrected and original precipitation data were used to simulate regional and global terrestrial carbon cycles using the prognostic biosphere model Vegetation Integrative Simulator for Trace Gases (VISIT). Following bias correction, the model results showed differences in zonal mean photosynthesis uptake and respiration release ranging from −2.0 to +3.3 Pg C yr−1, compared with the original data. The difference in the global terrestrial net carbon exchange rate was 0.3 Pg C yr−1, reflecting the compensation of coincident increases or decreases in carbon sequestration and respiration loss. At the regional scale, the ecosystem carbon cycle and canopy structure, including seasonal variations in autotrophic and heterotrophic respiration and total biomass, were strongly influenced by the input precipitation data. The results highlight the need for precise precipitation data when estimating the global terrestrial carbon balance.

Current Carbon Balance of the Forested Area in Sweden and its Sensitivity to Global Change as Simulated by Biome-BGC

Ecosystems ◽  
2006 ◽  
Vol 9 (6) ◽  
pp. 894-908 ◽  
Author(s):  
Fredrik Lagergren ◽  
Achim Grelle ◽  
Harry Lankreijer ◽  
Meelis Mölder ◽  
Anders Lindroth
Keyword(s):  
Global Change ◽  
Carbon Balance ◽  
Forested Area
Sign in / Sign up

Export Citation Format

Share Document