ESTIMATING CARBON AND GREENHOUSE GAS EMISSIONS IN REMOTE REGIONS OF CANADA

With the recent thrust to convert forests in Ontario’s Clay Belt to agricultural land, a vital need arises to assess the attendant effects on carbon and greenhouse gas (GHG) emissions. This paper examines the possible effect of land conversion on soil organic carbon and GHG emissions within a study area in Northern Ontario, Canada, during the next two decades under different land management schemes. The study established a framework to conduct simulations with the DNDC model for agricultural lands and the CBM for forested areas. The methodology involves a unique change detection method for models’ land cover and disturbance inputs. The work highlights the improvement in carbon simulation accuracy from better inputs to carbon models. Furthermore, it addresses modalities to ensure fewer uncertainties are introduced while merging data from multiple geospatial data sources. The simulations demonstrated that the carbon sequestration potential in the forests was almost double the soil organic carbon accumulation in the agricultural lands. Validations done for the estimation of carbon sequestered included comparisons of the carbon model outputs from field survey data from 2018–2021. In most sites, the carbon amounts from the computer models compared to those from the field survey, within limits of error. The average uncertainties in GHG emissions ranged from ~0.5% to 12.8%.

Improving the accuracy of estimating greenhouse gas absorption remains an urgent problem. Identification of the ratio of carbon stocks in soils and stand biomass of young and mid-aged forests will allow clarifying the direction of carbon fluxes in forest ecosystems during the development period most productive for atmospheric decarbonization. Increasing the accuracy of carbon stocks in components of forest ecosystems is necessary to recognize the real absorption capacity of Russian forests at the international level. The purpose of this study was to determine the carbon stocks in stand biomass and soils of young and mid-aged forests in the Republic of Tatarstan, as well as their ratio for forests of different species composition and origin. The studies were conducted on 6 sample plots in the most common forest stands aged 10 to 40 years. Organic carbon stocks in soils, stand biomass and other components of forest ecosystems located on sod-podzolic soils were determined. Total carbon stocks, the share of individual components and the ratio of stocks in stand biomass and soils were calculated. It was found that carbon stocks in the biomass of young stands of natural origin ranged from 8.5 to 50.8 t/ha, while in artificial stands they were 123.0 t/ha, and in mid-aged forests – 102.6–173.4 t/ha. Maximum carbon stocks were found in the biomass of stands of mid-aged birch forest, minimum — in young birch forest. Total organic carbon stocks in the studied ecosystems can vary by up to five times and range from 41.4 t/ha to 208.4 t/ha. The share of stand biomass in the structure of total ecosystem stocks ranged from 20.4 % to 91.4 %. Carbon stocks in sod-podzolic soils of the sample sites varied from 5.5 t/ha to 38.9 t/ha. This was lower than the reference values, but even in this case, soil carbon stocks account for 4.1 % to 73.7 % of the total ecosystem carbon stocks. Clarification of carbon stocks in soils of forested areas should be continued. Perhaps, regional databases on soil carbon stocks should be created, taking into account not only the species and age composition of the forest, but also the taxonomic affiliation of soils. In a 10-year-old birch forest the ratio of carbon stocks in the stand and soil was 3:10, in a 25-year-old birch forest it changed to 11:2, in a young pine forest of natural origin it was about 2:1, in artificial pine plantations of the same age it was 22:1. In natural birch forests, during the transition from young forests of age class I to mid-aged forests, carbon stocks in stand biomass increased by 20.5 times. The results obtained demonstrate the active participation of young and mid-aged natural forests in atmospheric decarbonization, with the main carbon sink at this stage of forest ecosystem development occurring in phytomass. Carbon stocks in soil are more conservative. The ratio of carbon stocks in stand biomass and soils of young aspen and middle-aged oak forests was close to the values for natural forests of other species of the same age. Carbon stocks in stand biomass of artificial pine planting was 2.5 times higher than in natural pine forest of the same age (25 years). Further research is required to draw scientifically grounded conclusions on the contribution of natural and planted forests to carbon sequestration.

High rates of deforestation in the Brazilian Amazon have the potential to alter the storage and cycling of carbon (C) and nitrogen (N) across this region. To investigate the impacts of deforestation, we quantified total aboveground biomass (TAGB), aboveground and soil pools of C and N, and soil N availability along a land-use gradient in Rondonia, Brazil, that included standing primary forest, slashed primary and secondary forest, shifting cultivation, and pasture sites. TAGB decreased substantially with increasing land use, ranging from 311 and 399 Mg ha–1 (primary forests) to 63 Mg ha–1 (pasture). Aboveground C and N pools declined in patterns and magnitudes similar to those of TAGB. Unlike aboveground pools, soil C and N concentrations and pools did not show consistent declines in response to land use. Instead, C and N concentrations were strongly related to percent clay content of soils. Concentrations of NO3-N and NH4-N generally increased in soils following slash-and-burn events along the land-use gradient and decreased with increasing land use. Increasing land use resulted in marked declines in NO3-N pools relative to NH4-N pools. Rates of net nitrification and N-mineralization were also generally higher in postfire treatments relative to prefire treatments along the land-use gradient and declined with increasing land use. Results demonstrate the linked responses of aboveground C and N pools and soil N availability to land use in the Brazilian Amazon; steady reductions in aboveground pools along the land-use gradient were accompanied by declines in inorganic soil N pools and transformation rates.

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BackgroundNutrient cycling in tropical forests has a large importance for primary productivity, and decomposition of litterfall is a major process influencing nutrient balance in forest soils. Although large-scale factors strongly influence decomposition patterns, small-scale factors can have major influences, especially in old-growth forests that have high structural complexity and strong plant-soil correlations. Here we evaluated the effects of forest structure and soil properties on decomposition rates and stabilization of soil organic matter using the Tea Bag Index (TBI) in an old-growth riparian forest in southeastern Brazil. These data sets were described separately using Principal Components Analysis (PCA). The main axes for each analysis, together with soil physical properties (clay content and soil moisture), were used to construct structural equations models that evaluated the different parameters of the TBI, decomposition rates and stabilization factor. The best model was selected using Akaike’s criterion.ResultsForest structure and soil physical and chemical properties presented large variation among plots within the studied forest. Clay content was strongly correlated with soil moisture and the first PCA axis of soil chemical properties, and model selection indicated that clay content was a better predictor than this axis. Decomposition rates presented a large variation among tea bags (0.009 and 0.098 g·g− 1·d− 1) and were positively related with forest structure, as characterized by higher basal area, tree density and larger trees. The stabilization factor varied between 0.211–0.426 and was related to forest stratification and soil clay content.ConclusionsThe old-growth forest studied presented high heterogeneity in both forest structure and soil properties at small spatial scales, that influenced decomposition processes and probably contributed to small-scale variation in nutrient cycling. Decomposition rates were only influenced by forest structure, whereas the stabilization factor was influenced by both forest structure and soil properties. Heterogeneity in ecological processes can contribute to the resilience of old-growth forests, highlighting the importance of restoration strategies that consider the spatial variation of ecosystem processes.

Influence of hydromorphic soil conditions on greenhouse gas emissions and soil carbon stocks in a Danish temperate forest

Forest conversions may lead to an accumulation of carbon in vegetation, but little is known about changes in soil C storage with establishment of plantation forests. Understanding these effects is important to addressing issues relevant to ecosystem function and productivity, and to global balance of carbon. The study investigated the effects of the created coniferous plantations on former beech and pasture sites on the soil organic carbon storage. The major forest-related land-uses in the high mountainous regions of central Stara Planina Mountain were investigated: mountainous pasture, coniferous plantations (planted on previous pasture and beech forests between four and five decades ago) and natural beech forests. The experimental data of soil properties, conducted in 2005, 2006 and 2007, were used in determining the variations in organic carbon storage in forest litter and in mineral soil under different land-use patterns. At each site five representative soil profiles were opened and described giving a total 75 soil samples from the soil layers respectively at 0-10, 10-30 and 30-50 cm depth. A total of 55 samples from forest floor layers (Aol, Aof, Aoh and greensward) were collected with 25:25 cm plastic frame. The main soil properties were determined in accordance with the standardized methods in the Laboratory of soil science at the Forest Research Institute - BAS. The IPCC Good Practice Guidance for Land Use, Land Use Change and Forestry was used to estimate the soil organic carbon stock in soil and litter. The results obtained showed that the SOC stock was quite similar among forest land-uses. The conversion of natural beech forests to coniferous plantations in studied region is related with slightly expressed decrease in soil carbon storage. The values of SOC stocks in 0-50 cm soil layer in these sites were 8.5 (?2.1) tones/ha for pine and 11.0 (?1.4) tones/ha for spruce, while under the natural beech forest it was 14.8 (?1.0) tones/ha. The SOC stock in mountainous pasture was 20.7 (? 6.5) tones/ha, while in spruce plantation created on previous pasture it was 13.5 (?2.7) tones/ha. Our finding showed that forest conversions effect in central Stara Planina Mountain is expressed by decrease in SOC stock related with losses of carbon from the upper mineral soil decades after creation of coniferous plantations. Nevertheless the relatively large organic carbon storage in forest litter in the spruce plantations compensated C lost from mineral soil after the land-use change. The overall carbon stock both in forest litter and soil under plantations ranged from 56 tones/ha (pine) to 77 tones/ha (spruce), while under natural beech forest and pasture the values were 70 and 81 tones/ha respectively. But in terms of stability C sequestrated in mineral soil is more desirable than C sequestrated in forest floor which are more vulnerable to decomposition following disturbances. The application of silvicultural activities in coniferous plantations created by conversion of forest lands or grasslands in the region of central Balkan is desirable to improve the carbon sequestration in soils.

Land use type is an important factor influencing greenhouse gas emissions from soils, but the mechanisms involved in affecting potential greenhouse gas (GHG) emissions in different land use systems are poorly understood. Since the northern regions of Canada and China are characterized by cool growing seasons, GHG emissions under low temperatures are important for our understanding of how soil temperature affects soil C and N turnover processes and associated greenhouse gas emissions in cool temperate regions. Therefore, we investigated the effects of temperature on the emission of N2O, CO2, and CH4 from typical forest and grassland soils from China and Canada. The soils were incubated in the laboratory at 10°C and 15°C under aerobic conditions for 15 days. The results showed that land use type had a large impact on greenhouse gas emissions. The N2O emissions were significantly higher in grassland than in forest soils, while CO2 emissions were higher in forest than in grassland soils. Grassland soils were weak sources of CH4 emission, while forest soils were weak sinks of atmospheric CH4. The global warming potential of forest soils was significantly greater than that of grassland soils. Soil pH, C/N ratio, and soluble organic carbon concentrations and clay content were dominant factors influencing the emissions of N2O and CO2, respectively. Increasing temperature from 10°C to 15°C had no effects on CH4 flux, but significantly increased N2O emissions for all studied soils. The same pronounced effect was also found for CO2 emission from forest soils. Indications from this study are that the effects of land use type on the source–sink relationship and rates of GHG emissions should be taken into consideration when planning management strategies for mitigation of greenhouse gas emissions in the studied region, and temperature changes must be taken into account when scaling up point- or plot-based N2O and CO2 flux data to the landscape level due to large spatial and temporal variations of temperature that exist in the field. The reader is cautioned about the limitation with incubation studies on a limited number of samples/locations, and care need to be exercised to extrapolate the result to field conditions.

Land use change is one of the major factors affecting soil degradation. Growing population pressure has increased land use change with more negative effects on soil carbon storage and overall soil properties. The objective of this study was to assess the effect of land use changes on soil organic carbon (SOC) stock and selected soil physicochemical properties in Gobu Sayyo, Western Ethiopia. Soil samples were collected from three adjacent land uses, that is, forest land, grazing land, and cultivated land, at 0-20 and 20-40 cm soil depths. A total of 36 composite soil samples were collected, and the major soil properties and SOC storage of the area were analyzed and computed based on their standard procedures. SOC stock was significantly (p < 0.05) higher (43.09-81.86 t ha-1) in forest land and was significantly lower (38.08-43.09 t ha-1) in cultivated land at the top 20 cm. SOC stock decreased with depth in all land uses. Changes in land use and soil depth affected the physical and chemical properties of soil. The physical soil property such as bulk density (BD) was higher (1.62 g cm-3) in the cultivated land, whereas the lowest (1.08 g cm-3) was recorded in the forest at 0-20 cm depth. Comparatively, the moisture content was higher (25.89%) under forest land at the depth of 20-40 cm and was lower (11.22%) under cultivated land. The chemical soil properties like exchangeable Ca2+, Mg2+, and K+ were higher in forest lands. Organic carbon, available phosphorus (AvP), total nitrogen (TN), exchangeable calcium (ex.Ca2+), exchangeable magnesium (ex.Mg2+), exchangeable potassium (ex.K+), and cation exchange capacity (CEC) were lower under cultivated lands. pH increased with depth and was higher under forest land and lower under cultivated land. Soils of the study area are in general acidic to slightly acid, with pH values ranging from 4.6 to 6.02. The pH, SOC, TN, AvP, and CEC were higher under forest land compared to cultivated and grazing lands. It can be concluded that SOC stocks and the physical and chemical properties were affected by land use change and depth. Therefore, reducing the intensity of cultivation, adopting integrated soil fertility management, and maintaining forest land must be practiced to save the soil of the area from degradation.

The study was conducted in the forest concession area of PT. Diamond Raya Timber, Riau Province, Indonesia. Measurement and calculation carbon stocks in soil and vegetation of tropical peat forest should be done accurately to anticipate carbon trading. The objective of the study is to estimate carbon stocks in soil and vegetation in 4 forest conditions. The study found that biomass and carbon stocks in the soil was 8 times higher than in the vegetation in primary forest condition, and 10 times in logged over forest and secondary forest condition. Carbon stocks in vegetation and soil were 189.45 ton C ha -1 and 1537.37 ton C ha -1 in primary forest, 161.76 ton C ha -1 , and 1713.77 ton C ha -1 in logged over area, 139.05 ton C ha -1 and 1486.39 ton C ha -1 in secondary forest, and 43.09 ton C ha -1 and 1205.59 ton C ha -1 in degraded forest. Allocation of carbon stocks in the standing trees in primary forest, logged over area, secondary forest, and degraded forest were 70, 60, 62, and 7% respectively.

Dairy production delivers nutrient-dense food but it also constitutes a major source of greenhouse gas (GHG) emissions. Feed formulation plays a central role in shaping both productivity and the climate footprint of dairy systems. This thesis investigated how feed ration formulation can reduce GHG emissions from Swedish high-producing dairy production whilst maintaining productivity. This was addressed across multiple system levels, from the individual animal to the regional food system. Two feeding trials with dairy cows and heifers evaluated animal performance and enteric methane (CH4) emissions. Study I compared two pelleted concentrate mixes, formulated with low-carbon-footprint (CF) by-products (BYP) and/or domestically sourced (DOM) ingredients, to a commercially available mix (COM). Both reduced feed-related GHG emissions without compromising feed intake, milk yield, or enteric CH4 emissions from high-producing (43.3 ± 5.4 kg ECM/d) Swedish Holstein cows. Study II tested a ration designed for forage scarcity, where whole-crop wheat silage was partially incorporated (50:50 DM basis) in grass-clover silage-based diets fed to Holstein and Nordic Red heifers. This substitution did not negatively affect feed intake, growth rate, or enteric CH4 emissions. Results from these trials were integrated into a farm-level life cycle assessment (Study III). At the farm level, when compared to COM, BYP decreased total farm-level GHG emissions (-6%) and land use (-3.8%), whilst DOM achieved smaller reductions in farm-level GHG emissions (-2.1% to -2.6%) but increased land use (up to +6.8%). At the regional level (Study IV), scenario modelling of dairy production in northern Sweden illustrated trade-offs among climate footprint, land use, feed self-sufficiency, and milk output. This thesis demonstrates that feed rations based on low-CF ingredients can reduce GHG emissions from high-yielding Swedish dairy production without compromising animal performance. However, the environmental outcomes depend on ingredient choice and system boundaries, highlighting the need to evaluate feeding strategies at multiple system levels to inform sustainable dairy development.

The European Union (EU) climate objectives rely on sustainable agriculture. This research assesses greenhouse gas (GHG) emissions and key agricultural indicators in Latvia from 2020 to 2022. This research aims to assess the developmental trends of agricultural GHG emissions and farming indicators in Latvia to identify strategies or future investigations necessary to mitigate GHG emissions and enhance sustainability. In Latvia, agriculture accounted for 21-22% of total GHG emissions in carbon dioxide (CO2) equivalents from 2020 to 2023, where total GHG emissions decreased from 10,507 thousand tons in 2020 to 9,981 thousand tons in 2023, in CO2 equivalents. Nitrous oxide (N2O) emissions were the most common in agriculture, accounting for 49% (1,115 kt CO2 equivalent) in 2022, followed by methane (CH4) at 47%. Despite livestock showing significant declines, dairy cows decreased by 12% from 136,035 to 119,042 between 2020 and 2023, while cattle overall decreased by only 8% from 398,989 to 368,057. The number of sheep and pigs in Latvia decreased by 15% and 5%, respectively, while the number of poultry increased by 1%. The GHG emissions from agriculture remained virtually unchanged. The amount of agricultural land area increased by 11% to 1,883,286 hectares in 2023. The increased land use for agriculture, combined with a decline in livestock numbers, resulted in a significant decrease in cattle density. This highlights the need for future evaluation of the reasons and methodology applied to Latvia's GHG emissions in the agricultural sector, to determine what other factors contributed to the unchanged GHG levels, and to identify further reduction possibilities for emissions.

&amp;lt;p&amp;gt;GHG emissions from drained peatlands in Southeast Asia contribute about 68% of the total regional emissions. Monitoring of land use dynamics on peatlands is necessary to quantify resulting climate impact. Optical satellite-based spatial land cover (LC) analyses are challenging in tropical regions due to high cloud covers. To overcome the limitation, we used the annual medians of spectral bands of Landsat 7/8 and Sentinel-2 which included all available observations per pixel and year for assessing LC in the Peatland Hydrological Units (PHUs) in North Kalimantan, Indonesia, for 2013, 2016 and 2019. Peatlands cover 290,000 ha of the 350,000 ha PHU area. In 2019, half of them still appeared to be covered by primary peat swamp forest (PSF). Drainage-based land use in the PHUs had expanded from 2013 to 2019, from 14 percent to nearly 30 percent of the total peatland area, with oil palm plantations covering more than half of the area under land use. Despite remaining data scarcity in some parts of the study area, which led to misclassifications, f1 scores classification accuracies range between 0.76 and 0.83.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In combination with a derived peatland map, greenhouse gas (GHG) emissions from land use on peatlands were calculated for the study years and a set of future GHG emission scenarios developed based on IPCC emission factors.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Peatland conversion between 2013 and 2019 led to a doubling of GHG emissions from land use reaching 3.24 Mt CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-eq yr&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; in 2019. As only 8% of the peatland area in the North Kalimantan PHUs falls under the moratorium, whereas 69% is designated as plantation concessions, we expect PSF conversion to continue and the area of degraded peatland to increase. In the &amp;amp;#8220;business-as-usual&amp;amp;#8221; (BAU) scenario with conversion rates as between 2013 and 2019, GHG emissions would reach about 10 Mt CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-eq per year by 2050. In the &amp;amp;#8220;stop new drainage&amp;amp;#8221; scenario, conversion would stop in 2020 and GHG emissions would remain at 3.24 Mt CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-eq yr&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. The cumulative avoidance potential until 2050 of the latter scenario is 48 %, compared to the BAU scenario. Complete rewetting of all drained peatlands by 2025 and halting any new drainage would until 2050 avoid 190.5 Mt CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-eq, i.e. 89%, compared to the BAU scenario. These avoidances will, however, only be achieved when the average annual water table depth after rewetting reaches or exceeds the peat surface. Otherwise, Indonesia&amp;amp;#8217;s NDC assumption of a zero peat decomposition in restored peatlands will not be achieved.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;To reduce expansion of drainage-based land use and associated GHG emissions, all peatland outside existing concessions in North Kalimantan would need to be covered by the Indonesian Moratorium. In parallel, existing concessions for drainage-based land use should be cancelled or replaced by concessions for wet peatland use, such as paludiculture.&amp;lt;/p&amp;gt;

Environmental factors, including greenhouse gas (GHG) emissions and soil organic carbon (SOC), should be considered when building a sustainable biofuel supply chain. This work developed a three‐step optimization approach integrating a geographical information system‐based mixed‐integer linear programming model to economically optimize the biofuel supply chain on the premise of meeting certain GHG emission criteria. The biomass supply grid cell was considered first, based on a maximum level of GHG emissions, prior to economic optimization. The optimization simultaneously considered dual‐feedstock sourcing, selection between distributed and centralized configurations, and the impact of maintaining SOC balance in agricultural soil on biomass availability. The applicability of the modeling approach was demonstrated through a case study that optimized a dual‐feedstock renewable jet fuel supply chain via a gasification‐Fischer–Tropsch (gasification‐FT) conversion pathway in 2050 under three biomass availability scenarios. The case study results show that the differences in procurement costs and GHG emissions between energy crops and agricultural residues have a large impact on the layout of the supply chain. The supply‐chain configuration tends to be more centralized with large‐scale biorefineries when a supply region has an intensive and centralized distribution of biomass resources. The cost‐supply curves demonstrated the technical potential of biofuels that could be obtained at a certain level of cost. Additionally, sensitivity analysis shows that the GHG emission credit from producing extra electricity during the gasification‐FT process will be significantly reduced with a rising share of renewable electricity generation in the future. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley &amp; Sons Ltd.

Assessing the environmental impacts of production- and consumption-side measures in sustainable agriculture intensification in the European Union