Spatiotemporal Variation of Terrestrial Carbon Sequestration in Tropical Urban Area (Case Study in Surakarta District, Indonesia)

The value of terrestrial carbon sequestration in urban areas, due to lack of vegetation as a carbon sink, is rarely studied. In fact, urban areas have high carbon emission values, which must be minimised. On the other hand, the value of carbon sequestration in urban areas is very dynamic due to natural factors from the environment and non-natural factors from anthropogenic activities. The main objectives of this study are to identify the carbon dioxide sequestration in urban areas, especially in tropical climates, and to determine the dynamics of carbon sequestration in urban areas for a year. The results show that carbon sequestration in tropical urban areas has a significant value compared with urban areas in temperate climates. This condition happens because there are still green open spaces in gardens and agricultural lands. The value of carbon sequestration in this tropical urban area experiences monthly dynamics caused by rainfall variation and anthropogenic activities, such as land conversion and plant type conversion in agricultural lands.

Widespread reforestation before European influence on Amazonia

An estimated 90 to 95% of Indigenous people in Amazonia died after European contact. This population collapse is postulated to have caused decreases in atmospheric carbon dioxide concentrations at around 1610 CE, as a result of a wave of land abandonment in the wake of disease, slavery, and warfare, whereby the attendant reversion to forest substantially increased terrestrial carbon sequestration. On the basis of 39 Amazonian fossil pollen records, we show that there was no synchronous reforestation event associated with such an atmospheric carbon dioxide response after European arrival in Amazonia. Instead, we find that, at most sites, land abandonment and forest regrowth began about 300 to 600 years before European arrival. Pre-European pandemics, social strife, or environmental change may have contributed to these early site abandonments and ecological shifts.

A comparative assessment of Non-destructive and destructive methods for precise volume estimation of mango (Mangifera indica) trees

Terrestrial carbon sequestration is a natural process towards carbon mitigation in which perennial trees play a vital role. Total biomass of the tree can be measured by a destructive and Non-destructive method. Since tree felling is ban in India, Non-destructive measurements by allometric equations have been widely used for the estimation of tree biomass, which is derived from the destructive method. The present study focused on estimating mango (Mangifera indica) wood logs volume both by destructive and Non-destructive methods in ICAR-Central Institute of Subtropical Horticulture, Lucknow. In Non-destructive method, all required physical parameters were recorded from different positions and further calculated by T2: log formula = ?h (r12+r22+r1 r2)/3; T3: cylindrical shape formula = ?r2h with mean value and T4: cylindrical shape formula = ?r2h with maximum value. The calculated volume of mango wood logs was compared with the obtained volume by T1:Water displacement method. ANOVA was used to compare volume generated from several methods. The results showed that average volume obtained by T2 and T3 methods was found less than the T1 method, which was 13.69 % and 12.95 %, respectively. The volume obtained by T4 was found close to the T1. The study minimized the error while estimating the biomass of mango trees with the essential parameter, the wood volume. Calculating the volume of major branches in the mango tree will make it easier to calculate accurate AGB by a Non-destructive method. The estimated AGB will be helpful to calculate the amount of sequestered carbon and contribution toward mitigating atmospheric carbon dioxide by mango cultivated areas.

Assessment of Temporal Change in Terrestrial Carbon Sequestration Capacity With Land Use Land Cover Change Along the Metro Corridor in Kochi, India

Kochi is undergoing drastic environmental changes with the developmental activities. Kochi metro rail project is one among them. The present study focuses on the decrease in carbon sequestration capacity due to clearing of vegetation, especially trees and paddy fields for metro rail. Metro rail corridor extends to a length of 18.22 km with 16 stations. Total extent of the study area is 777.7 ha covering 200 m buffer zone on both sides of metro corridor. This study integrates analysis of satellite images using GIS along with carbon inventory data from field surveys. IRS P6 LISS IV satellite sensor images of 26th February 2013 and 5th February 2017 are used for the study. Ground-truthing is done for 25 sampling plots. The study showed a total reduction of 35.8 ha of vegetation area which is converted into built-up area. The total carbon content is reduced by 6877 tons in an area of 777.7 ha ie: 8.84t/ha on an average. Maximum reduction has occurred along the metro rail and station zones, where maximum numbers of gown up trees were removed.

Emergent constraints on global carbon-climate feedbacks from regional atmospheric aridity

<p>The vulnerability of terrestrial carbon sequestration to increases in fossil fuel emissions is one of the most important feedbacks in the Earth System.  However, the relative importance of temperature and moisture controls on regional terrestrial CO2 fluxes varies substantially and yet critical to unraveling their roles in carbon-climate feedbacks. Here, we employ the Hierarchical Emergent Constraint (HEC) to quantify an emergent relationship between spatially- explicit sensitivities of carbon fluxes to atmospheric aridity across an ensemble of Earth System Models (ESMs) and the long-term sensitivity of tropical land-carbon storage to atmospheric aridity.  Our results show that interannual fluctuations in atmospheric aridity, as an important driver of atmospheric water demand for plants, substantially impact the terrestrial carbon sink. However, this analysis, which is conditioned on observations, leads to a substantially lower feedback than predicted by ESMs alone. Furthermore, we show that a relatively small number of regions have an out-sized impact on global carbon climate-feedbacks.  These findings underscore the role of both water and temperature on carbon-climate feedbacks while the regional attribution provided by HEC points to areas for further process-based research.</p>

Exploring the control of phenological patterns of leaf function and tree growth in European tree species

<p>Trees in temperate climates show distinct seasonality of leaf photosynthetic function and tree growth, which has strong influence on the annual cycle of terrestrial carbon sequestration. Thus, there are intense efforts to explore phenological pattern of leaf photosynthetic function and tree growth in temperate tree species and understand their internal and external regulation. In this presentation, we summarize our past research in this field, combining results from different experimental studies and field observations on a large number of European tree species. We show not only the well-known dependency of the onset of spring bud burst and leaf development on temperature and photoperiod and their large inter- and intra-specific variability, but also refer to further, fairly unknown, environmental factors. We give examples how varying soil properties and drought stress may interact with temperature on the seasonal timing of bud burst, photosynthesis, shoot growth and autumnal leaf senescence. Finally, we give information on the temporal coordination of bud burst, canopy greening and tree growth, showing strong differences among European tree species. With the collected information, we identify potential sources of uncertainty in approaches predicting the seasonal timing of leaf photosynthetic activity and tree growth with climate warming.</p><p> </p>

Global maps of current and future nitrogen mineralization

<p>Soil nitrogen is a prominent determinant of plant growth, with nitrogen (N) availability being a key driver of terrestrial carbon sequestration. The local availability of soil N is thus crucial to our understanding of broad-scale trends in soil fertility, productivity, and carbon dynamics. Here, we provide global, high-resolution maps of current and future (2050) potential net nitrogen mineralization (N-min), revealing global patterns in soil N availability. Highest mineralization rates are found in warm and moist tropical regions, leading to a strong latitudinal gradient in N-min. We observed a positive correlation of N-min rates with human population density and net primary productivity. Projected climate conditions for 2050 suggest that N availability will further decrease in areas of low N availability and increase in areas of high N availability, thereby intensifying current global trends. These results shed light on the core processes governing productivity at a global scale, providing an opportunity to improve the accuracy of plant biomass and climate models.</p>