Belowground Biomass Carbon Stocks Research Articles

Consequences of plateau pika disturbance on plant-soil carbon and nitrogen in alpine meadows.

The presence of burrowing mammals can have extensive effects on plants and soils, creating bare soil patches in alpine meadows and potentially altering plant-soil carbon (C) and nitrogen (N). This study focuses on the plateau pika (Ochotona curzoniae) to examine the responses of plant-soil C and N to a small burrowing mammal from quadrat scale to plot scale. The density of active burrow entrances in disturbed plots was used as an indicator of the disturbance intensity of plateau pikas. The study found that the below-ground biomass (BGB) and its C and N, as well as soil C and N concentrations were significantly lower in bare soil areas than in vegetated areas and undisturbed plots. This shows that the quadrat scale limited the estimation of the C and N sequestration potential. Therefore, further research on the plot scale found that the disturbance by plateau pika significantly reduced plant biomass and BGB carbon stock. However, plateau pika did not affect soil C and N stocks or ecosystem C and N stocks. These findings suggest the bare soil patches formed by plateau pika caused plant and soil heterogeneity but had a trade-off effect on plant-soil C and N stocks at the plot scale. Nevertheless, moderate disturbance intensity increased the C and N sequestration potential in grassland ecosystems. These results provide a possible way to estimate how disturbance by small burrowing mammals affects C and N cycling in grassland ecosystems while accurately assessing the effects of small burrowing mammal densities on C and N in grassland ecosystems.

Estimation of Aboveground and Belowground Carbon Stocks in Homegardens of Low Country Wet Zone, Sri Lanka


 
 
 Homegardens are one of the most significant and oldest types of land use systems in Sri Lanka which have been recognized as an essential component in providing a variety of ecosystem services. In these systems, trees and shrubs are grown together with food crops under family labor, creating a multitude of biological interactions. Due to rich tree diversity and density, homegarden agroforestry systems are known to have a great capacity to capture and store carbon in their biomass and soil, and thus greatly contribute to mitigation of climate change. Even though the importance of homegardens with regard to the above is highlighted significantly, large knowledge gaps remain on their total carbon storage potential, particularly in low country wet zone homegardens of Sri Lanka. Therefore, the current study aims to estimate the total aboveground and belowground carbon stocks of homegardens in Kalutara district. The study was conducted in ten homegardens ranging from 0.15 Ha to 0.43 Ha. The study focused on all perennial woody trees present in the homegardens. Heights and diameters at breast height (DBH) were measured in a total of 966 woody trees. Aboveground biomass of each tree was calculated nondestructively, using allometric equations which incorporated wood density, DBH and tree height. Belowground biomass was calculated using root: shoot ratios of trees. Total biomass of each tree was converted to total carbon stocks using a conversion factor of 0.5 extracted from literature, considering that total carbon stock of a tree is equivalent to half of its biomass. In order to get the total carbon stock, soil organic carbon (SOC) content of each home garden was analyzed in the laboratory from collected soil samples using the Loss-on-ignition method. Belowground biomass carbon stock and the SOC stock together were taken as the total belowground carbon stock of each homegarden. Estimated mean aboveground carbon stock was 91.4±11.4 Mg ha-1, while the mean belowground carbon stock was determined as 134.3±12.3 Mg ha-1 in low country wet zone home gardens. Aboveground carbon stock, together with the belowground carbon stock, was taken as the total carbon stock of the homegardens. Calculated total carbon stock per unit area for low country wet zone homegardens ranged between 179.873 Mg ha-1 and 286.606 Mg ha-1 with a mean value of 225.7±11.9 Mg ha-1. Above findings of the study present evidence for significant carbon storage capacity of low country wet zone homegardens.
 Keywords: Homegarden, Low country, Wet zone, Carbon stock, Climate change
 
 

Above- and Belowground Biomass Carbon Stock and Net Primary Productivity Maps for Tidal Herbaceous Marshes of the United States

Accurate assessments of greenhouse gas emissions and carbon sequestration in natural ecosystems are necessary to develop climate mitigation strategies. Regional and national-level assessments of carbon sequestration require high-resolution data to be available for large areas, increasing the need for remote sensing products that quantify carbon stocks and fluxes. The Intergovernmental Panel on Climate Change (IPCC) provides guidelines on how to quantify carbon flux using land cover land change and biomass carbon stock information. Net primary productivity (NPP), carbon uptake, and storage in vegetation, can also be used to model net carbon sequestration and net carbon export from an ecosystem (net ecosystem carbon balance). While biomass and NPP map products for terrestrial ecosystems are available, there are currently no conterminous United States (CONUS) biomass carbon stock or NPP maps for tidal herbaceous marshes. In this study, we used peak soil adjusted vegetation index (SAVI) values, derived from Landsat 8 composites, and five other vegetation indices, plus a categorical variable for the CONUS region (Pacific Northwest, California, Northeast, Mid-Atlantic, South Atlantic-Gulf, or Everglades), to model spatially explicit aboveground peak biomass stocks in tidal marshes (i.e., tidal palustrine and estuarine herbaceous marshes) for the first time. Tidal marsh carbon conversion factors, root-to-shoot ratios, and vegetation turnover rates, were compiled from the literature and used to convert peak aboveground biomass to peak total (above- and belowground) biomass and NPP. An extensive literature search for aboveground turnover rates produced sparse and variable values; therefore, we used an informed assumption of a turnover rate of one crop per year for all CONUS tidal marshes. Due to the lack of turnover rate data, the NPP map is identical to the peak biomass carbon stock map. In reality, it is probable that turnover rate varies by region, given seasonal length differences; however, the NPP map provides the best available information on spatially explicit CONUS tidal marsh NPP. This study identifies gaps in the scientific knowledge, to support future studies in addressing this lack of turnover data. Across CONUS, average total peak biomass carbon stock in tidal marshes was 848 g C m−2 (871 g C m−2 in palustrine and 838 g C m−2 in estuarine marshes), and based on a median biomass turnover rate of 1, it is expected that the mean NPP annual flux for tidal marshes is similar (e.g., 848 g C m−2 y−1). Peak biomass carbon stocks in tidal marshes were lowest in the Florida Everglades region and highest in the California regions. These are the first fine-scale national maps of biomass carbon and NPP for tidal wetlands, spanning all of CONUS. These estimates of CONUS total peak biomass carbon stocks and NPP rates for tidal marshes can support regional- and national-scale assessments of greenhouse gas emissions, as well as natural resource management of coastal wetlands, as part of nature-based climate solution efforts.

Carbon stocks and changes in biomass of Mediterranean woody crops over a six-year period in NE Spain

Carbon sequestration and storage in biomass is one of the most important measures to mitigate climate change. Mediterranean woody crops can sequestrate carbon in the biomass of their permanent structures for decades; however, very few studies have focused on an assessment of biomass and carbon sequestration in these types of crops. This study is the first to estimate above- and belowground biomass carbon stock in Mediterranean woody crops through a bottom-up approach in the NE Iberian Peninsula in 2013. Moreover, this is the first time that an assessment of the annual changes in carbon stock in the study area over a six-year period is presented. For this purpose, eight crop- and site-specific equations relating biomass or biometric variables to crop age were calculated. Most of the data were our own measurements, but unpublished data supplied from other authors as well as data from literature were also considered. Census of Agriculture data was used to scale results from individual data up to the municipality level at the regional scale. Results show that in woody cropland in NE Spain the total biomass carbon stock in 2013 was 5.48 Tg C, with an average value of 16.44 ± 0.18 Mg C ha−1. Between 2013 and 2019, although there was a 2.8% mean annual decrease in the area covered by woody crops, the carbon stock in the biomass of these crops increased annually by 3.8% due to the growth of the remaining woody cropland. This new estimation of carbon stocks may contribute to better understand carbon balances and serve as a baseline to global inventories. It may also serve to assess and manage carbon storage as an ecosystem service provided by Mediterranean woody cropland for mitigating climate change and, in combination with adaptive strategies, for supporting a productive and resilient agro-food system.

Estimation of aboveground and belowground carbon stocks in urban freshwater wetlands of Sri Lanka

BackgroundThe occurrence of climate change at an unprecedented scale has resulted in alterations of ecosystems around the world. Numerous studies have reported on the potential to slow down climate change through the sequestration of carbon in soil and trees. Freshwater wetlands hold significant potential for climate change mitigation owing to their large capacity to sequester atmospheric carbon dioxide (CO2). Wetlands among all terrestrial ecosystems have the highest carbon density and are found to store up to three to five times more carbon than terrestrial forests. The current study was undertaken to quantify carbon stocks of two carbon pools: aboveground biomass (AGB) and belowground biomass (BGB). Chosen study sites; Kolonnawa wetland and Thalawathugoda wetland park are distributed within the Colombo wetland complex. Colombo was recognized as one of the 18 global Ramsar wetland cities in 2018. A combination of field measurements and allometric tree biomass regression models was used in the study. Stratification of the project area was performed using the normalized difference vegetation index (NDVI).ResultsThe AGB carbon stock, across strata, is estimated to be in the range of 13.79 ± 3.65–66.49 ± 6.70 tC/ha and 8.13 ± 2.42–52.63 ± 10.00 tC/ha at Kolonnawa wetland and Thalawathugoda wetland park, respectively. The BGB carbon stock is estimated to be in the range of 2.47 ± 0.61–10.12 ± 0.89 tC/ha and 1.56 ± 0.41–8.17 ± 1.39 tC/ha at Kolonnawa wetland and Thalawathugoda wetland park, respectively. The total AGB carbon stock of Kolonnawa wetland was estimated at 19,803 ± 1566 tCO2eq and that of Thalawathugoda wetland park was estimated at 4180 ± 729 tCO2eq.ConclusionsIn conclusion, the study reveals that tropical freshwater wetlands contain considerable potential as carbon reservoirs. The study suggests the use of tropical freshwater wetlands in carbon sequestration enhancement plans in the tropics. The study also shows that Annona glabra, an invasive alien species (IAS), has the potential to enhance the net sink of AGB carbon in these non-mangrove wetlands. However, further studies are essential to confirm if enhanced carbon sequestration by Annona glabra is among the unexplored and unreported benefits of the species.

Terrestrial carbon stocks following 15 years of integrated watershed management intervention in semi-arid Ethiopia

Our study investigated the total terrestrial stock of organic carbon and its controlling factors in prevalent land‐use systems in semi-arid Ethiopia (610 mm of annual rainfall), as part of the impact assessment of the national Integrated Watershed Management (IWM) program. Above- and below-ground biomass and soil organic carbon (SOC) stocks of major land-use systems (i.e., exclosure, cropland, rangeland, and bare land) were quantified after field sampling along a topographic gradient. We found that aboveground carbon stocks peaked in the 15-year-old exclosures (9.08 ± 1.44 Mg ha−1) owing to intact woody and grass vegetation as well as substantial litter cover (>20% of the total biomass). Croplands cultivated with wheat and rangelands vegetated with perennial grasses showed average aboveground carbon stocks of 3.16 ± 0.24 and 1.45 ± 0.19 Mg ha−1, respectively. The belowground biomass carbon stock was particularly low in croplands (0.76 ± 0.09 Mg ha−1), exceeded by that in both exclosures and rangelands, where values averaged 3.67 ± 0.06 and 3.04 ± 0.42 Mg ha−1, respectively. The topsoil (0–30 cm) SOC stocks also varied with land-use systems but showed a different order, peaking in rangelands (53.9 ± 10.1 Mg ha−1) and exclosures (41.4 ± 8.1 Mg ha−1), followed by bare lands (29.0 ± 11.5 Mg ha−1) and croplands (26.4 ± 4.6 Mg ha−1). The sub-soils (30–100 cm) added 40% to this SOC storage. The greatest total SOC stock identified in exclosures that had been established primarily on degraded hillslopes may signify a successful restoration effort under the IWM program. However, croplands exhibited the lowest SOC stock, which implies the need for urgent interventions to improve the soil fertility.

Biomass and soil carbon along altitudinal gradients in temperate Cedrus deodara forests in Central Himalaya, India: Implications for climate change mitigation

Abstract Carbon inventories are urgently needed for understanding climate dynamics and implementing climate mitigation strategies, but such data is scarce in for forest ecosystem of Himalaya. Therefore, the present study focuses to supplement the existing information by estimating carbon stocks in temperate forests dominated by Cedrus deodara along the altitudinal gradients in the Central Himalaya. Three altitudes i.e., lower (1750 m), middle (1900 m) and upper (2050 m) of the stand was considered to understand and estimate biomass and soil carbon storage potential of the forests based on the standard protocol. The results showed that the soil carbon stock (SOC) decreased significantly with increasing soil depths and altitudes. Litterfall production in the forests varied adversely with altitude. Above and below-ground biomass carbon stock also decreased along with altitude. The study observed that the total carbon stock (soil, trees and forest floor) of the Cedrus deodara forest in different altitudes was 395.4 t ha−1 (lower altitude), 321.6 t ha−1 (middle altitude) and 282.5 t ha−1 (upper altitude). The estimates of the Cedrus forests would provide guidelines for estimating carbon for forest-based mitigation activities in the Himalayan region.