Carbon Storage Potential Research Articles

Sentinel-1 Backscatter Time Series for Characterization of Evapotranspiration Dynamics over Temperate Coniferous Forests

Forests’ ecosystems are an essential part of the global carbon cycle with vast carbon storage potential. These systems are currently under external pressures showing increasing change due to climate change. A better understanding of the biophysical properties of forests is, therefore, of paramount importance for research and monitoring purposes. While there are many biophysical properties, the focus of this study is on the in-depth analysis of the connection between the C-band Copernicus Sentinel-1 SAR backscatter and evapotranspiration (ET) estimates based on in situ meteorological data and the FAO-based Penman–Monteith equation as well as the well-established global terrestrial ET product from the Terra and Aqua MODIS sensors. The analysis was performed in the Free State of Thuringia, central Germany, over coniferous forests within an area of 2452 km2, considering a 5-year time series (June 2016–July 2021) of 6- to 12-day Sentinel-1 backscatter acquisitions/observations, daily in situ meteorological measurements of four weather stations as well as an 8-day composite of ET products of the MODIS sensors. Correlation analyses of the three datasets were implemented independently for each of the microwave sensor’s acquisition parameters, ascending and descending overpass direction and co- or cross-polarization, investigating different time series seasonality filters. The Sentinel-1 backscatter and both ET time series datasets show a similar multiannual seasonally fluctuating behavior with increasing values in the spring, peaks in the summer, decreases in the autumn and troughs in the winter months. The backscatter difference between summer and winter reaches over 1.5 dB, while the evapotranspiration difference reaches 8 mm/day for the in situ measurements and 300 kg/m2/8-day for the MODIS product. The best correlation between the Sentinel-1 backscatter and both ET products is achieved in the ascending overpass direction, with datasets acquired in the late afternoon, and reaches an R2-value of over 0.8. The correlation for the descending overpass direction reaches values of up to 0.6. These results suggest that the SAR backscatter signal of coniferous forests is sensitive to the biophysical property evapotranspiration under some scenarios.

Coupling analysis between cost and carbon emission of bamboo building materials: A perspective of supply chain

Bamboo building materials with carbon storage potential are considered to be the key to low carbon emissions and sustainable development in the construction industry. However, the willingness to pay and the carbon storage effect of bamboo materials still face major obstacles, and the supply chain needs to be optimised as it affects the economic and green benefits of bamboo building materials. This study aims to investigate the carbon emission and cost distribution of bamboo building materials, analyse the key influencing factors and propose an equilibrium optimisation strategy. Results indicate that ‘Carbonisation’, ‘Glue application’ and ‘anti-mould, anti-corrosion and drying’ in the production phase are the major contributors to carbon emissions, which are mainly generated by biomass fuel carbonisation kiln, adhesives and anti-mould preservatives. ‘Transportation from front-end factory to back-end factory” and ‘Transportation from back-end factory to construction site” in the supply phase are the largest obstacles to cost, and transportation distance is the key factor. The results were accepted by the manufacturer and facilitated the screening of the best equilibrium control strategy: clean energy replacement, use of new adhesives and anti-mould products and adjustment of transport distances. After the implementation of the optimisation strategy, carbon emissions were reduced by 40.10% and costs were reduced by 35.31%, indicating that the effect of the optimisation strategy is obvious. This study explores the carbon reduction potential of bamboo building materials, provides actionable guidance for producers of building materials and architects, and promotes the willingness of society to accept payment.

Carbon storages and sequestration potentials in remnant forests of different patch sizes in northern Ethiopia: an implication for climate change mitigation

Abstract Background Forests provide various ecosystem services. They are natural capitals that enhance nature to regulate itself via carbon sinks. However, anthropogenic and natural factors have altered their CO2 sequestration and carbon storage potentials. This study is aimed for examining the effect of patch size and biomass extraction on carbon stocks in northern Ethiopia. A total of 61 sample plots measuring 20 m × 20 m size each (0.04 ha) had been systematically assigned on patches classified into three size categories. However, the numbers of plots taken per patch were different with their sizes. Moreover, stump density has been computed at each plot to estimate the difference in the level of disturbance among patches. Carbon stocks had been estimated via models previously developed. One-way ANOVA was used to examine a variation in carbon stocks and sequestration potentials. Besides, a linear regression analysis was discretely done to examine the relationship between patch sizes, disturbance level, and carbon stocks. Results The overall aboveground biomass (ton ha−1) for the studied patches was 2059.13. There was a statistically significant variation in carbon stocks (ton ha−1) among patch size categories. The mean levels of disturbance ranges from 10.83% ± 1.30 to 30.8% ± 4.04. However, statistically significant difference in the level of disturbance was observed between large and small patch size categories, respectively (p < 0.05). Besides, a regression analysis confirmed a significant and negative relationship between patch size and patch disturbances (R2 = 0.65, p < 0.05). However, significant positive relation between carbon stocks (ton ha−1) and patch size (R2 = 0.53, p < 0.05) had observed. Conclusions In general, patch size and biomass extinction significantly influenced carbon stocks and CO2 sequestration potentials of forests. Consequently, with the pressing need to mitigate the effects of rising atmospheric CO2, maximizing carbon storage in the forest ecosystem is increasingly considered a viable management strategy. Therefore, disturbed land restoration, increasing forest patch size, sustainable management, and conservation of the existing remnant forest patch is needed to enhance carbon stocks and CO2 sequestration potentials.

Accounting for carbon flows into and from (bio)plastic in a national climate inventory

AbstractDespite the time‐dependent behavior of carbon stored in plastic materials, literature assessing carbon flows into and from plastic typically applies a static approach. To better understand the climate impacts of such storage, this study explores how carbon stored in plastics can contribute over time to the national climate inventory with various emphasis on recycling. This is accomplished by implementing material stock change estimations for carbon in plastic materials that follow first‐order decay and include impacts from recycling rates in the Integrated MARKAL‐EFOM System model generator for Sweden (TIMES‐Sweden). Thereafter, three approaches to how carbon released from the plastic material stock is accounted for in the national climate inventory were applied to determine how each approach affects resulting emission and net‐zero pathways in different recycling rate scenarios. An accounting approach that follows the first‐order decay pattern of material stocks was found to be important for capturing the impacts of recycling and for neither over‐ nor underestimating the emission impact from carbon stored in plastics. Accounting for carbon stored in plastics may provide important incentives for producing renewable plastics and reducing dependence on carbon removal technologies. Because of its synergies with recycling, the carbon storage potential of plastic products is well worth recognizing and promoting in a policy setting that aims for circularity. For Sweden, this reduces the need for bioenergy carbon capture and storage and makes more biomass‐based carbon and electricity available for use elsewhere in the energy system.

Assessing the potential of solubility trapping in unconfined aquifers for subsurface carbon storage

Carbon capture and storage projects need to be greatly accelerated to attenuate the rate and degree of global warming. Due to the large volume of carbon that will need to be stored, it is likely that the bulk of this storage will be in the subsurface via geologic storage. To be effective, subsurface carbon storage needs to limit the potential for CO2 leakage from the reservoir to a minimum. Water-dissolved CO2 injection can aid in this goal. Water-dissolved CO2 tends to be denser than CO2-free water, and its injection leads immediate solubility storage in the subsurface. To assess the feasibility and limits of water-dissolved CO2 injection coupled to subsurface solubility storage, a suite of geochemical modeling calculations based on the TOUGHREACT computer code were performed. The modelled system used in the calculations assumed the injection of 100,000 metric tons of water-dissolved CO2 annually for 100 years into a hydrostatically pressured unreactive porous rock, located at 800 to 2000 m below the surface without the presence of a caprock. This system is representative of an unconfined sedimentary aquifer. Most calculated scenarios suggest that the injection of CO2 charged water leads to the secure storage of injected CO2 so long as the water to CO2 ratio is no less than ~ 24 to 1. The identified exception is when the salinity of the original formation water substantially exceeds the salinity of the CO2-charged injection water. The results of this study indicate that unconfined aquifers, a generally overlooked potential carbon storage host, could provide for the subsurface storage of substantial quantities of CO2.

There and back again: Forty years of change in vegetation patterns in Irish peatlands

Northern peatlands play a disproportionally large role in the global carbon balance due to the massive amount of carbon stored in peat and ongoing sequestration. Vegetation composition and structure are recognised indicators for carbon sequestration and storage potential in these ecosystems, but decadal dynamics and roles of autogenic succession, climate, and land-use herein remain poorly understood.We assessed vegetation changes in the least disturbed centre of twelve Irish peatland reserves sampled across a gradient in temperature and precipitation between 1978(1983)–2021, combining re-classified traditional high-resolution vegetation maps with recent very high-resolution drone imagery. Specifically, we tested whether microform proportions of open water, wet hollow, moist lawn, and dry hummock had changed and explored to what extent changes were related to climate and land-use drivers.Results revealed that the studied peatlands underwent an overall unidirectional surface drying trend, with dry hummocks expanding at the expense of open water and wet hollow, while moist lawns remained approximately equal in proportions. The degree of change varied between the studied peatlands, with western blanket bogs and unrestored raised bogs experiencing more surface drying than mountain blanket bogs and raised bogs under hydrological restoration. While our results indicated climate and/or land-use as drivers of surface drying, our sample size was too small to make definitive conclusions about their exact role.The overall change from wet to dry surface conditions between 1978 and 2021 occurred at a much faster rate than hitherto reported for these slow-changing ecosystems. This raises concern for the future resilience of peatlands to changes in climate and land-use, as well as their potential impact on the peatland carbon balance.

Allometric models for estimating biomass storage and carbon stock potential of Oldeania alpina (K. Schum.) Stapleton forests of south-western Ethiopia

Ethiopia has the largest bamboo resource base in Africa. However, due to the lack of species-specific models, little is known about the biomass storage, carbon stock and sequestration potential of bamboo forests. Here, species-specific allometric models are presented and the potential biomass and carbon storage of the Oldeania alpina (K. Schum.) Stapleton forests of Ethiopia are quantified. A total of 42 bamboo culms covering the full range of sizes were destructively sampled, with a diameter at breast height (DBH) ranging from 3 to 7.1 cm, height (H) of 7.8 – 14.2 m, and age 1 – 6-year-old. Allometric equations were formulated in the form of power models for estimating the total aboveground biomass (TAGB) of O. alpina. TAGB was regressed against DBH and H individually and in combination. Finally, the allometric models were validated and selected based on model performance statistics. Allometric equations for estimating TAGB with higher coefficient of determination (adj.R2), lower residual standard error (RSE), and low Akaike information criterion (AIC) values fitted best. Relationships between observed and predicted TAGB were statistically significant (p≤0.05) for the selected models. The developed allometric models can be applied to the estimation of the biomass storage potential of O. alpina forests of Ethiopia.

Global Distribution of Carbohydrate Utilization Potential in the Prokaryotic Tree of Life.

Microorganisms dominate all ecosystems on Earth and play a key role in the turnover of organic matter. By producing enzymes, they degrade complex carbohydrates, facilitating the recycling of nutrients and controlling the carbon cycle. Despite their importance, our knowledge regarding microbial carbohydrate utilization has been limited to genome-sequenced taxa and thus heavily biased to specific groups and environments. Here, we used the Genomes from Earth's Microbiomes (GEM) catalog to describe the carbohydrate utilization potential in >7000 bacterial and archaeal taxa originating from a range of terrestrial, marine and host-associated habitats. We show that the production of carbohydrate-active enzymes (CAZymes) is phylogenetically conserved and varies significantly among microbial phyla. High numbers of carbohydrate-active enzymes were recorded in phyla known for their versatile use of carbohydrates, such as Firmicutes, Fibrobacterota, and Armatimonadota, but also phyla without cultured representatives whose carbohydrate utilization potential was so far unknown, such as KSB1, Hydrogenedentota, Sumerlaeota, and UBP3. Carbohydrate utilization potential reflected the specificity of various habitats: the richest complements of CAZymes were observed in MAGs of plant microbiomes, indicating the structural complexity of plant biopolymers. IMPORTANCE This study expanded our knowledge of the phylogenetic distribution of carbohydrate-active enzymes across prokaryotic tree of life, including new phyla where the carbohydrate-active enzymes composition have not been described until now and demonstrated the potential for carbohydrate utilization of numerous yet uncultured phyla. Profiles of carbohydrate-active enzymes are largely habitat-specific and reflect local carbohydrate availability by selecting taxa with appropriate complements of these enzymes. This information should aid in the prediction of functions in microbiomes of known taxonomic composition and helps to identify key components of habitat-specific carbohydrate pools. In addition, these findings have a high relevance for the understanding of carbohydrate utilization and carbon cycling in the environment, the process that is closely link to the carbon storage potential of Earth habitats and the production of greenhouse gasses.

Effect of climatic factors on leaf litter decomposition dynamics of a subtropical scrub forest under field and microcosm conditions

This study investigated the leaf litter decomposition dynamics of Hayat-ul-Mir subtropical scrub forest in Pakistan. Litter bags were incubated for 360 days in the forest to elucidate the effect of elevation and incubation time and for 90 days in microcosms to investigate the effect of projected warming (+2.3°C and +4.5°C) and soil moisture (M15% and M20%) on litter decomposition. Site elevation significantly affected k and T50% while time affected mass loss, residual weight, remaining C and N at p < .01 in field. After 360 days of decomposition, ∼48% residual weight with 11.7 ± 0.4% of C and 1.07 ± 0.06% of N was observed in the litter bags. Higher elevations (850–1020 m) were recorded with low C and N mineralization compared to 600–850 m elevations indicating their potential for long term carbon storage. Warming (+4.5°C) significantly accelerated the pace of decomposition in microcosms with comparatively higher mass loss (+26%), k (+34%), and soil CO2 efflux (+50%) reducing T50% by 77 days than observed under ambient conditions (To). The effect of moisture was insignificant but comparatively, decomposition was high at M20%. The study concludes that future warming will significantly accelerate the pace of nutrient cycling reducing the carbon storage potential of this ecosystem.

High carbon storage and oxygen (O2) release potential of Mahagony (Swietenia macrophylla) woodlot plantation in Bangladesh

Woodlot plantation takes our attention nowadays because of having high wood value, biomass and carbon stock. It also has considerable potential for regulating climate change by sinking CO2. This study investigated the market value of Swietenia macrophyllawoodlots concerning the current carbon trade mechanism, local timber and oxygen value.The carbon-di-oxide equivalence (CO2e) and release oxygen (O2 Release) ranged from 125.5 to 1004.5 Mg/ha (mean 436.3 Mg/ha) and 91.25–730.26 Mg/ha (mean 317.2 Mg/ha), respectively. Form carbon trade, the Swietenia macrophylla woodlots owner will earn 4,285–34,470 BDT/ha (mean 14,900 BDT/ha). It also seemed that the present market value of release oxygen (O2 Release) ranged from 3.2 to 25.5 million BDT/ha (average 11.1 million BDT/ha). However, the study area's average DBH, height, density, and basal area were 18.9 cm, 12.6 m, 1233 stem/ha, and 36.6 m2/ha, respectively. The above-ground biomass, below-ground biomass, and total biomass ranged from 45.9 to 389.7 Mg/ha (mean 166.5 Mg/ha), 22.5–157.7 Mg/ha (mean 71.2 Mg/ha), and 68.4–547.4 Mg/ha (mean 237.7 Mg/ha) correspondingly. Besides, the produced wood volume ranged from 64.95-1225.19 m3/ha (average 481.48 m3/ha). While the price of wood ranged from 0.8 to 15.14 million BDT/ha (mean 5.95 million BDT/ha). However, the above-ground, below-ground, and total carbon ranged 22.97–194.85 Mg/ha (mean 87.27 Mg/ha, 11.23–78.85 Mg/ha (35.61 Mg/ha), and 34.2–273.7 Mg/ha (118.89 Mg/ha) independently.Moreover, our three developed basal area-based allometric models are fit for calculating the carbon stock of Swietenia macrophylla woodlots. This study explores the potentiality of woodlots in Bangladesh. Policymakers should encourage the farmers to create more woodlots that actively participate in climate change mitigation.

Fighting climate change with bamboo in Africa: The case of Kyela, Rungwe and Mufindi districts – Tanzania

Responding to the African Forest Landscape Restoration Initiative (AFR100), 32 countries have committed to restoring more than 100 million hectares of land across Africa by 2030. Bamboo is being discussed as one of the nature-based solutions to achieve this ambitious target in the face of climate change. Major advantages are that it is a fast-growing versatile woody grass that can prosper in degraded lands. So far, landscape restoration strategies are driven by climate policy debates where bamboo is largely neglected. Most empirical research on the potential of bamboo for fighting climate change has been conducted in Asia, leaving open questions on the transferability of results to the African context. In this paper, we contribute to the debate by investigating how bamboo can contribute to climate change mitigation, especially in degraded ecosystems. Taking Tanzania as an example, we lay a special focus on bamboo carbon sequestration and storage potential and assess the dynamics of carbon stocks: (i) across an elevation gradient, (ii) between indigenous and exotic bamboo species, and (iii) between intensively and extensively managed bamboo ecosystems. We collected data from 60 destructive sample plots and estimated biomass carbon stocks in the aboveground carbon pool. The weighted average biomass, carbon stocks, and sequestration rates obtained were 52.4 t ha−1, 26.2 t C ha−1, and 19 t C ha−1yr−1, respectively. The ANOVA revealed a significant variation in carbon stocks across an elevation gradient and between bamboo species (P < 0.05), which explained 22% and 11% of the total variation. We also observed a significant two-way-factors interaction between elevation versus species and silvicultural management options (P < 0.05), explaining 12% and 5% of the total variation, respectively. Similarly, a three-way interaction between all factors was significant, accounting for 4% of the total aboveground carbon variation. Our results contribute to developing a more nuanced picture of the advantages and disadvantages of incorporating bamboo in landscape restoration efforts. The novel findings may be a first step toward unlocking future climate finance in Africa.

Assessment of carbon balance attribution and carbon storage potential in China's terrestrial ecosystem

Carbon sink in terrestrial ecosystems is critical for achieving carbon neutrality; however, its environmental sensitivity and potential remain uncertain. A comprehensive framework was established to assess the carbon balance attribution and carbon storage potential. The net ecosystem productivity was integrated with the maximum entropy model and the patch-generating land use simulation model for analysis. In 2017, ecosystems in China produce 0.44 Pg C and store 1.66 Pg C, with sources in the west and sinks in the east. The Sichuan Basin, North China Plain, Loess Plateau, Inner Mongolia Plateau and Northeast China Plain experience the historical carbon source-to-sink conversion. The potential for the sink-to-source conversion increases from central to eastern and western China and precipitation contributes 52.3%. A high possibility of potential sink-to-source conversion concentrates in Eastern Qinghai-Tibet Plateau, middle-lower Yangtze River plain and eastern coastal areas of China. The carbon sink in terrestrial ecosystems of China is expected to be 23.58 Pg C in 2030, with the central subtropical broad-leaved evergreen zone accounting for 21.33%. The risk of the decline in carbon stocks is 0.45–0.54 Pg C. The results serve as scientific references for achieving carbon neutrality and sustainable development goals.

Estimation and application of spatial distribution of carbon storage in Wushe reservoir watershed based on environmental indicators in Taiwan

The forest land carbon storage assessment model proposed in this study belongs to the IPPC Tier-3 method. The model operates through a conceptual model that includes environmental parameters such as Photosynthesis Index (NDVI), Soil Depth Index (TWI) and Canopy Height Model (CHM). The model is verified by the IPPC Tier-2 method, which can effectively construct the distribution of watershed-scale forest carbon stock. The spatial distribution of carbon fluxes can be obtained from the carbon stock information of the two periods. The carbon flux index can be used to describe the distribution of carbon stocks and carbon emissions in the watershed, and then the location of negative carbon flux (vegetation degradation) can be extracted as a value-added application of vegetation restoration hotspots. The accuracy of the model estimation in forest land verification is high, reaching a significant level of 0.1%, which can faithfully reflect the carbon stock of forest land. However, in non-forest lands, carbon stock estimates tend to exhibit carbon storage potential due to land-use disturbances. A combination of conceptual models and environmental indicators is of great help in assessing watershed carbon stocks and fluxes.

Climate benefits of wooden construction in urban context

Wooden construction materials have two climate benefits compared to non-wooden options: lower lifecycle emissions and a carbon storage potential. This study estimates the implications of replacing concrete buildings with wooden ones for a period of 35 years in Helsinki metropolitan area, Finland. The study has three main steps. First, the greenhouse gas (GHG) emissions difference between concrete and wooden buildings is estimated. Next, we select the most accurate carbon storage potential of wooden buildings. Finally, we compare future wooden and concrete building scenarios regarding the climate benefits for the metropolitan area. We use data provided by the regional authority of the study area on predicted residential building construction. According to our findings, switching to wooden construction in urban areas can have a significant climate benefit for the studied region. Increasing wooden construction can cut carbon emissions by 0.56 Mt and increase the carbon storage by 1.83 Mt in the study area, an amount that is four times bigger than the yearly emissions from traffic in the same urban area. The findings are not only useful for the city of Helsinki but also to other global cities which have committed to carbon neutral strategies and have sustainable forestry practices available.

Terrestrial carbon sequestration under future climate, nutrient and land use change and management scenarios: a national-scale UK case study

Carbon sequestration (Cseq) in soils and plant biomass is viewed as an important means of mitigating climate change. Recent global assessments have estimated considerable potential for terrestrial Cseq, but generally lack sensitivity to climate warming, nutrient limitations and perspective on local land use. These are important factors since higher temperatures can accelerate the decomposition of soil organic matter, nutrient availability affects plant productivity, while land use pressures put broader constraints on terrestrial organic matter inputs and storage. Here, we explore the potential for Cseq under changing land use, climate and nutrient conditions in a UK-based national scale case study. We apply an integrated terrestrial C–N–P cycle model with representative ranges of high-resolution climate and land use scenarios to estimate Cseq potential across the UK. If realistic UK targets for grassland restoration and afforestation over the next 30 years are met, we estimate that an additional 120 TgC could be sequestered by 2100 (similar to current annual UK greenhouse gas emissions or roughly 7% of net emission cuts needed in meeting net zero), conditional on climate change of <2 °C. Conversely, we estimate that UK arable expansion would reduce terrestrial carbon storage by a similar magnitude. The most pessimistic climate trajectories are predicted to cause net losses in UK soil carbon storage under all land use scenarios. Warmer climates substantially reduce the potential total terrestrial carbon storage gains offered by afforestation and grassland restoration. We conclude that although concerted land use change could make an important moderate contribution to national level Cseq for countries like the UK, soil Cseq only provides a contribution if we are on a low emission pathway, and is therefore conditional on deep global cuts to emissions from fossil fuels, deforestation and soil degradation.

Urban biodiversity and carbon sinks – do they overlap? Case study of Helsinki Metropolitan Area, Finland.

Amongst the greatest global environmental challenges of our time are climate change and biodiversity loss. Feedback mechanisms associated with warming climate could also lead to large-scale biodiversity losses worldwide and it would therefore be logical to seek mitigation methods beneficial for both impact categories. However, research on the topic remains relatively scarce. Our study focuses on two key aspects of environmental sustainability, carbon storage capacity and species biodiversity, to determine whether these correlate at different levels of urban density. GIS-datasets are utilized to estimate the carbon storage potential and species diversity across the urban landscape as well as their association at different levels of urban land use intensity. The results highlight the importance of small green spaces at dense urban cores, indicating that in environments where green infrastructure is limited high species diversity and carbon storage are more likely to overlap, whereas at urban fringe the observed relationship is weaker and divergence of the two impact categories becomes more probable. The study draws attention to the role fragmented, limited green spaces play at establishing functioning ecosystems at local scale and provides new information to support the development of sustainable planning and management practices across the urban land use gradient.

Estimation and Mapping of Actual and Potential Grassland Root Carbon Storage: A Case Study in the Altay Region, China

The actual root carbon storage (ARCS) and potential root carbon storage (PRCS) of grasslands play an important role in the global carbon balance and carbon neutralization. However, estimation of these indicators is difficult. In addition, their spatial patterns and crucial driving factors also require clarification. In this study, an approach for accurate estimation of ARCS and PRCS was developed incorporating a support vector machine model and high-accuracy surface modeling. Based on field data collected from Altay Prefecture in 2015, the estimation accuracy (R2) of root biomass in the 0–10, 10–20, and 20–30 cm soil layers of grassland were 0.73, 0.63, and 0.60, respectively. In addition, the spatial patterns of actual root carbon density (ARCD) and potential root carbon density (PRCD) were analyzed. The ARCD increased with the increase in elevation. High PRCD was located on hillsides with a gentle slope. The dominant interaction factors for the ARCD spatial pattern were temperature and precipitation, whereas the main interaction factors for the PRCD pattern were temperature and slope. The grassland ARCS and PRCS in Altay Prefecture were estimated to be 48.52 and 22.69 Tg C, respectively. We suggest there is considerable capacity to increase grassland ARCS in the study area.

Quantification of the Carbon Sequestration Potential of a 31-year-old Tree-based Intercropping System in Southern Ontario, Canada

Carbon (C) storage potential was quantified for four tree species which are commonly incorporated into tree-based intercropping (TBI) systems and compared with conventional agricultural systems in southern Ontario, Canada. In the 31-year-old TBI system at the University of Guelph’s Agroforestry Research Station, Norway spruce (&lt;em&gt;Picea abies&lt;/em&gt;), white cedar (&lt;em&gt;Thuja occidentalis&lt;/em&gt;), black walnut (&lt;em&gt;Juglans nigra&lt;/em&gt;) and red oak (&lt;em&gt;Quercus rubra&lt;/em&gt;) were planted in tree rows, intercropped with soybean (&lt;em&gt;Glycine max&lt;/em&gt;). In the conventional agricultural field, soybean was grown in a monocropping system. Above and belowground tree and crop C content, soil organic C (SOC) and system level C was quantified for each tree species as well as the conventional agricultural system. Red oak TBI systems had the highest SOC followed by black walnut, Norway spruce and white cedar with values of 93.2, 83.9, 78.1, and 72.2 t C ha&lt;sup&gt;-1&lt;/sup&gt;, respectively. Red oak TBI systems also had the highest mean tree C content, followed by black walnut, Norway spruce and white cedar, with values of 299.7, 285.8, 255.4 and 70.1 kg C tree&lt;sup&gt;-1&lt;/sup&gt;, respectively. Total system level C, which incorporated SOC, tree C content and tree planting densities was 134.8, 126.4, 115.7, 95.6 and 75.6 t C ha&lt;sup&gt;-1&lt;/sup&gt; respectively for spruce, oak, walnut and cedar TBI systems and the agricultural field. TBI systems provide higher C sequestration potentials than conventional agricultural fields, and Norway spruce and red oak should be included into TBI systems in southern Ontario to maximize C sequestration benefits.

Biomass Estimation and Carbon Storage of Taxodium Hybrid Zhongshanshan Plantations in the Yangtze River Basin

As a pivotal wetland tree, Taxodium hybrid Zhongshanshan has been widely planted in the region of Yangtze River for multipurpose of ecological restoration, field shelter, landscape aesthetics as well as carbon sequestration. However, the carbon allocation patterns across distinct stages of stand development of T. Zhongshanshan are poorly documented. Using a sample of 30 trees which were destructively harvested, this study compared 3 models for assessing aboveground biomass. Furthermore, a linear seemingly unrelated regression (SUR) approach was introduced to fit the system of the best selected model that ensured the additivity property. On this basis, biomass and carbon storage of T. Zhongshanshan stands in the Yangtze River Basin (YRB) were fairly estimated. Specifically, the study developed height-diameter at breast (H-DBH) function. The results showed that the selected 3-parameter polynomial model performed better, and the SUR approach provided more accurate estimates of leaf and stem fractions. The total tree biomass was 53.43, 84.87, 140.67, 192.71 and 156.65 t ha−1 in the 9-, 11-, 13-, 15-, and 22-year-old T. Zhongshanshan stands, and contributed averagely 94.40% of the ecosystem biomass accumulation. The current T. Zhongshanshan stands in the YRB area can store 124.76 to 217.64 t ha−1 carbon, of which total tree ranges from 25.32 to 90.89 t ha−1, with 55.19% to 77.66% storing in the soil. The T. Zhongshanshan had continuous potential for carbon storage during its growth, particularly in the incipient stages. The findings of this research are firsthand information for forest managers for the sustainable management of T. Zhongshanshan in the YRB and similar subtropical areas.

Soil carbon storage potential of acid soils of Colombia's Eastern High Plains

Improving soil organic carbon (SOC) storage enhances soil quality and mitigates climate change. Agricultural and livestock specialists increasingly view tropical grasslands as a potential target for storing more soil carbon while boosting productivity. Earlier research in the 1990s showed the promise of improving SOC storage in the Eastern High Plains of Colombia. But these studies were limited to two experimental stations, without focusing on conditions on farms or under variable management. This research examined whether those early studies did indeed reflect possibilities for improving SOC storage and livestock productivity. We measured SOC stocks at one of the experiment stations from previous research and on farms throughout the study area in Colombia's Eastern High Plains. Complementarily our team sampled other predominant land uses to map SOC storage across the nearly 1 million ha study area. Using that information, we also constructed scenarios suggesting changes in SOC and productivity based on land-use changes. The high SOC accumulation found at experimental sites in the 1990s declined 24 years later. However, SOC storage was over 27 Mg ha−1 yr−1 higher than reference native savanna sites, with an accumulation rate of 0.96 Mg ha−1 yr−1. On farms under variable management, improved pastures stored 10 Mg ha−1 more SOC than degraded pastures or native savanna. For the whole region, we estimate that carbon storage observed across soils and land use of the 1 million ha study area could store 0.08 Gt of carbon down to 1 m depth, with wide variation across the region. While the SOC measured in grasslands in the early 1990s did not persist under inadequate management over the period of two decades, the potential to accumulate SOC of Colombia's Eastern High Plains through appropriate management is high, pointing to a sustainable livestock strategy that boosts productivity and reduces emissions.