Forest Carbon Balance Research Articles

Belowground carbon dynamics in Scots pine stands

Boreal forest soils are globally one of the most extensive carbon storages, whereas soil respiration (CO2 efflux) forms the largest carbon flux from the ecosystem to the atmosphere. Current changes in the world climate may have unpredictable effects on belowground carbon processes, and thereby, on the carbon balance of boreal forests. To better understand the various processes in soil and to quantify the potential changes in the carbon cycle, forest-floor respiration (RFF) was partitioned into five different components, and tree-root respiration (RR) was estimated, using four different methods in a mature boreal Scots pine (Pinus sylvestris L.) stand in southern Finland. Non-structural carbohydrate (NSC) concentrations in tree roots were determined, and carbon allocation to belowground by trees was estimated with the whole-tree carbon model ‘CASSIA’. In addition, RR and heterotrophic soil respiration (RH) were separated using root exclusion in seven coniferous forests along a latitudinal gradient in Northern and Central Europe. The RR comprised almost half of the RFF, the RH almost a third, and ground vegetation and respiration of mycorrhizal hyphae the remaining fifth in the boreal Scots pine stand. While the annual RR decreased throughout the first three study years, the RH increased when the mycorrhizal roots were excluded from the treatments. The RR and most of the NSC concentrations were higher in the warmer years and lower in the cooler, as estimated with most of the methods. Three methods resulted in rather similar RR estimations, while the RR estimated with root incubation was significantly lower. The RR was over 50% of the annual photosynthesis in the northernmost forest stand, whereas in the southernmost stand it was only up to 15%. Carbon allocation to the belowground, as modelled with CASSIA was a third of the annual photosynthesis on average and almost 5% for the symbiotic mycorrhizae.

Current state and future development potential of the oak forests in the floodplain of the Ural River (West Kazakhstan)

The article provides information on the current state of the oak forests of the Ural River floodplain (West Kazakhstan) based on the analysis of forest inventory materials (as of 01.01.1992 and 01.01.2016) and field surveys. The study of the dynamics of the oak forests (Quercus robur L.) is timely and relevant due to the important ecological role of the oak forests as the most resilient among floodplain forests, and the need to preserve their biological diversity near the south-eastern limit of the natural distribution range. Over a 24-year period, the area of the oak forests decreased by 98.7 hectares (4 %). During the study there has been a decrease in the stand density and site productivity, as well as the predominance of mature stands reproduced through re-sprouting. Pure oak forests or oak forest with an insignificant admixture of Ulmus laevis Pall., Populus alba L. and Acer negundo L. are the most common oak forest types. Natural regeneration of Q. robur is unsatisfactory or absent altogether. The total projective cover of the grass layer is up to 90 %, however, its floristic diversity is low. Authors of the article present estimates of the carbon balance of the oak forests under various management scenarios, obtained by using the EX-ACT tool. We stress the need to develop measures aimed at preserving these unique forests, including promotion of the natural regeneration of Q. robur and the creation of sustainable forest plantations. To reduce the impact of anthropogenic factors on oak forests (felling, grazing, recreation, etc.), we propose to create a specially protected area in the region.

Assessments of the Forest Carbon Balance in the National Climate Policies of Russia and Canada

Assessments of the Forest Carbon Balance in the National Climate Policies of Russia and Canada

Demonstration of large area forest volume and primary production estimation approach based on Sentinel-2 imagery and process based ecosystem modelling

ABSTRACT Forest biomass and carbon monitoring play a key role in climate change mitigation. Operational large area monitoring approaches are needed to enable forestry stakeholders to meet the increasing monitoring and reporting requirements. Here, we demonstrate the functionality of a cloud-based approach utilizing Sentinel-2 composite imagery and process-based ecosystem model to produce large area forest volume and primary production estimates. We describe the main components of the approach and implementation of the processing pipeline into the Forestry TEP cloud processing platform and produce four large area output maps: (1) Growing stock volume (GSV), (2) Gross primary productivity (GPP), (3) Net primary productivity (NPP) and (4) Stem volume increment (SVI), covering Finland and the Russian boreal forests until the Ural Mountains in 10 m spatial resolution. The accuracy of the forest structural variables evaluated in Finland reach pixel level relative Root Mean Square Error (RMSE) values comparable to earlier studies (basal area 39.4%, growing stock volume 58.5%, diameter 35.5% and height 33.5%), although most of the earlier studies have concentrated on smaller study areas. This can be considered a positive sign for the feasibility of the approach for large area primary production modelling, since forest structural variables are the main input for the process-based ecosystem model used in the study. The full coverage output maps show consistent quality throughout the target area, with major regional variations clearly visible, and with noticeable fine details when zoomed into full resolution. The demonstration conducted in this study lays foundation for further development of an operational large area forest monitoring system that allows annual reporting of forest biomass and carbon balance from forest stand level to regional analyses. The system is seamlessly aligned with process based ecosystem modelling, enabling forecasting and future scenario simulation.

Mapping Amazon Forest Productivity by Fusing GEDI Lidar Waveforms with an Individual-Based Forest Model

The Amazon rainforest plays an important role in the global carbon cycle. However, due to its structural complexity, current estimates of its carbon dynamics are very imprecise. The aim of this study was to determine the forest productivity and carbon balance of the Amazon, particularly considering the role of canopy height complexity. Recent satellite missions have measured canopy height variability in great detail over large areas. Forest models are able to transform these measurements into carbon dynamics. For this purpose, about 110 million lidar waveforms from NASA’s GEDI mission (footprint diameters of ~25 m each) were analyzed over the entire Amazon ecoregion and then integrated into the forest model FORMIND. With this model–data fusion, we found that the total gross primary productivity (GPP) of the Amazon rainforest was 11.4 Pg C a−1 (average: 21.1 Mg C ha−1 a−1) with lowest values in the Arc of Deforestation region. For old-growth forests, the GPP varied between 15 and 45 Mg C ha−1 a−1. At the same time, we found a correlation between the canopy height complexity and GPP of old-growth forests. Forest productivity was found to be higher (between 25 and 45 Mg C ha−1 a−1) when canopy height complexity was low and lower (10–25 Mg C ha−1 a−1) when canopy height complexity was high. Furthermore, the net ecosystem exchange (NEE) of the Amazon rainforest was determined. The total carbon balance of the Amazon ecoregion was found to be −0.1 Pg C a−1, with the highest values in the Amazon Basin between both the Rio Negro and Solimões rivers. This model–data fusion reassessed the carbon uptake of the Amazon rainforest based on the latest canopy structure measurements provided by the GEDI mission in combination with a forest model and found a neutral carbon balance. This knowledge may be critical for the determination of global carbon emission limits to mitigate global warming.

Accounting for forest management in the estimation of forest carbon balance using the dynamic vegetation model LPJ-GUESS (v4.0, r9710): implementation and evaluation of simulations for Europe

Abstract. Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to account for the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the implementation of a forest management module containing even-age and clear-cut and uneven-age and continuous-cover management alternatives in the dynamic vegetation model LPJ-GUESS. Different age and species structure initialisation strategies and harvest alternatives are introduced. The model is applied at stand and European scales. Different management alternatives are applied in simulations of European beech (Fagus sylvaticus) and Norway spruce (Picea abies) even-aged monoculture stands in central Europe and evaluated against above-ground standing stem volume and harvested volume data from long-term experimental plots. At the European scale, an automated thinning and clear-cut strategy is applied. Modelled carbon stocks and fluxes are evaluated against reported data at the continent and country levels. Including wood harvest in regrowth forests increases the simulated total European carbon sink by 32 % in 1991–2015 and improves the fit to the reported European carbon sink, growing stock, and net annual increment (NAI). Growing stock (156 m3 ha−1) and NAI (5.4 m3 ha1 yr1) densities in 2010 are close to reported values, while the carbon sink density in 2000–2007 (0.085 kg C m−2 yr1) equates to 63 % of reported values, most likely reflecting uncertainties in carbon fluxes from soil given the unaccounted for forest land-use history in the simulations. The fit of modelled and reported values for individual European countries varies, but NAI is generally closer to reported values when including wood harvest in simulations.

Environmental Effects on Normalized Gross Primary Productivity in Beech and Norway Spruce Forests

The strong effects of climate change are expected to negatively impact the long-term resilience and function of forest ecosystems, which could lead to changes in forest carbon balance and productivity. However, these forest responses may vary with local conditions and forest types. Accordingly, this study was carried out to determine gross primary productivity (GPP) sensitivity to changes in environmental parameters. Central European beech (at Štítná) and spruce species (at Bílý Kr̆íz̆ and Rájec), growing under contrasting climatic conditions, were studied. The comparative analyses of GPP were based on a five-year-long dataset of eddy covariance fluxes during the main growing season (2012–2016). Results of forest GPP responses with changes in environmental factors from a traditional Stepwise multiple linear regression model (SMLR) were used and compared with Random forest (RF) analyses. To demonstrate how actual GPP trends compare to potential GPP (GPPpot) courses expected under near-optimal environmental conditions, we computed normalized GPP (GPPnorm) with values between 0 and 1 as the ratio of the estimated daily sum of GPP to GPPpot. The study confirmed the well-known effect of total intensity of the photosynthetically active radiation and its diffuse fraction on GPPnorm across all the forest types. However, the study also showed the secondary effects of other environmental variables on forest productivity depending on the species and local climatic conditions. The reduction in forest productivity at the beech forest in Štítná was presumed to be mainly induced by edaphic drought (anisohydric behaviour). In contrast, reduced forest productivity at the spruce forest sites was presumably induced by both meteorological and hydrological drought events, especially at the moderately dry climate in Rájec. Overall, our analyses call for more studies on forest productivity across different forest types and contrasting climatic conditions, as this productivity is strongly dependent on species type and site-specific environmental conditions.

Excellent video on carbon balance in local Eucalypt Forests

Excellent video on carbon balance in local Eucalypt Forests

The initial overreaction of carbon cycle to elevated atmospheric humidity levels off over time - a FAHM study in a young birch forest

Ecosystem responses to climate change are mainly predicted based on short-term studies. However, the first response can be a temporary overreaction, different from the later response of the more acclimated ecosystem. The current paper is a follow-up study of our previous article, where the effect of elevated atmospheric humidity on forest ecosystem carbon (C) balance was studied in a young silver birch (Betula pendula Roth) forest after two years of humidification. Here, we present the C balance of the same forest measured two years later when humidification treatment had been performed for four years. We revealed that the higher C sequestration capacity of the humidified birch forest ecosystem was an initial overreaction, which levelled off after four years of humidification, when the ecosystem became more acclimated to wetter conditions. Understorey production reacted rapidly and strongly by increasing belowground production more than twofold, but this reaction ceased after four years of humidification treatment. Trees responded to a lesser extent, and the initially decreased aboveground growth was recovered after four years of humidification, when the biomass allocation to tree fine-roots was increased. Our results showed that at early forest age, understorey plant production dominated in the whole ecosystem C sequestration capacity. But in the later stage, the most important C sink was biomass production of birches, and since the tree biomass production no longer differed between the treatments, C sequestration of the whole ecosystem did not differ either. The findings confirm that a preliminary reaction of an ecosystem can be different from the later response, which needs to be taken into account when prognosing the climate change consequences for carbon sequestration.

Changes in energy and livestock systems largely explain the forest transition in Austria (1830–1910)

Achieving a global forest transition, that is a shift from deforestation to reforestation, is important for climate-change mitigation. Forest transitions are enabled by socioecological processes, including land displacement, agricultural intensification and woodfuel substitution for other energy, but their respective contributions remain poorly understood. Here, by means of a scenario approach we quantify the importance of enabling conditions of the forest transition in Austria between 1830 and 1910 and their overall emissions implications, including the forest carbon sink potential in the hypothetical absence of wood use. We combine historical databases on land use, biomass production and energy use and an empirical dynamic forest growth model to develop five hypothetical counterfactual scenarios. The scenarios assume food and energy consumption in the absence of woodfuel substitution, food imports and three variations of agricultural intensification and assess effects on forest change and carbon balances. We find that the absence of any of the enabling conditions would have completely depleted forest biomass by 1910. Livestock efficiency gains and woodfuel substitution, two rarely discussed drivers of forest change, were equally important as yield increase and land displacement. The cumulative forest sink potential in the absence of any wood extraction throughout the period was found to be about twice the forest carbon stock in 1830. All counterfactual scenarios led to increasing overall emissions, “no woodfuel substitution” being closest to the historical trend. Our work lays the ground for a new typology of forest transitions according to the socioecological processes that enable them.

Forest floor fluxes drive differences in the carbon balance of contrasting boreal forest stands

The forest floor provides an important interface of soil-atmosphere CO2 exchanges but their controls and contributions to the ecosystem-scale carbon budget are uncertain due to measurement limitations. In this study, we deployed eddy covariance systems below- and above-canopy to measure the spatially integrated net forest floor CO2 exchange (NFFE) and the entire net ecosystem CO2 exchange (NEE) at two mature contrasting stands located in close vicinity in boreal Sweden. We first developed an improved cospectra model to correct below-canopy flux data. Our empirical below-canopy cospectra models revealed a greater contribution of large- and small-scale eddies in the trunk space compared to their distribution in the above-canopy turbulence cospectra. We found that applying the above-canopy cospectra model did not affect the below-canopy annual CO2 fluxes at the sparse pine forest but significantly underestimated fluxes at the dense mixed spruce-pine stand. At the mixed spruce-pine stand, forest floor respiration (Rff) was higher and photosynthesis (GPPff) was lower, leading to a 1.4 times stronger net CO2 source compared to the pine stand. We further found that drought enhanced Rff more than GPPff, leading to increased NFFE. Averaged across the six site-years, forest floor fluxes contributed 82% to ecosystem-scale respiration (Reco) and 12% to gross primary production (GPP). Since the annual GPP was similar between both stands, the considerable difference in their annual NEE was due to contrasting Reco, the latter being primarily driven by the variations in NFFE. This implies that NFFE acted as the driver for the differences in NEE between these two contrasting stands. This study therefore highlights the important role of forest floor CO2 fluxes in regulating the boreal forest carbon balance. It further calls for extended efforts in acquiring high spatiotemporal resolution data of forest floor fluxes to improve predictions of global change impacts on the forest carbon cycle.

Combined effects of natural disturbances and management on forest carbon sequestration: the case of Vaia storm in Italy

• Key message Natural disturbances and management are key drivers for forest carbon balance. We modelled the impact of Vaia storm on forest sink at national scale in Italy. We demonstrate that after Vaia, carbon fluxes among pools and through harvested wood products from salvage logging limit the carbon losses. Our findings can improve the effectiveness of mitigation actions under disturbance scenarios. • Context Climate change increasingly modifies frequency and magnitude of extreme events, such as windstorms, with subsequent strong impacts not only on forest health and stability but also on the forest carbon balance.• Aims We aim to assess the combined impact of natural disturbances and forest management on the overall forest carbon accounting, including the mitigation potential from harvested wood products.• Methods We modelled the impact of Vaia storm on the evolution of forest carbon balance at national scale until 2030. We considered the effect of Vaia storm in combination with current management practices and salvage logging.• Results Our results suggest that the overall carbon sink decreased only by 4% due to Vaia, because of internal carbon transfers among forest pools (about 3.1 Mt C from living biomass to dead organic matter), and that the potential negative effects of salvage logging, removing about 1.2 Mt C from dead organic matter, can be counterbalanced by long-term carbon accumulation in harvested wood products.• Conclusion Based on our findings, there is an increasing need to robustly consider, through novel approaches (e.g. comprehensive and integrated modelling framework), the effects of natural disturbances in current accounting frameworks, with the final purpose to improve the effectiveness of mitigation strategies in the forestry sector.

Carbon loss from boreal forest wildfires offset by increased dominance of deciduous trees.

In boreal forests, climate warming is shifting the wildfire disturbance regime to more frequent fires that burn more deeply into organic soils, releasing sequestered carbon to the atmosphere. To understand the destabilization of carbon storage, it is necessary to consider these effects in the context of long-term ecological change. In Alaskan boreal forests, we found that shifts in dominant plant species catalyzed by severe fire compensated for greater combustion of soil carbon over decadal time scales. Severe burning of organic soils shifted tree dominance from slow-growing black spruce to fast-growing deciduous broadleaf trees, resulting in a net increase in carbon storage by a factor of 5 over the disturbance cycle. Reduced fire activity in future deciduous-dominated boreal forests could increase the tenure of this carbon on the landscape, thereby mitigating the feedback to climate warming.

Carbon cycling after boreal forest fire

Fire Ecology Wildfire activity has been increasing in the boreal forests of the Northern Hemisphere, releasing carbon into the atmosphere from biomass and soil, with potential feedback to climate warming. In a long-term study, Mack et al. analyzed wildfire impacts on the carbon balance of boreal forest in Alaska, with particular focus on forest-regeneration patterns. After fire, the species composition in most of the study sites changed from black spruce to a mixture of conifers and deciduous broadleaf tree species. The stands that had shifted to deciduous dominance stored fivefold more soil carbon than stands that returned to black spruce dominance. Therefore, the functional traits of deciduous trees compensated for the combustion loss of soil carbon, pointing to a potential mitigation of the feedback effect of boreal forest fire to climate warming. Science , this issue p. [280][1] [1]: /lookup/doi/10.1126/science.abf3903

Sources and sinks of greenhouse gases in the landscape: Approach for spatially explicit estimates

Climate change mitigation is a global response that requires actions at the local level. Quantifying local sources and sinks of greenhouse gases (GHG) facilitate evaluating mitigation options. We present an approach to collate spatially explicit estimated fluxes of GHGs (carbon dioxide, methane and nitrous oxide) for main land use sectors in the landscape, to aggregate, and to calculate the net emissions of an entire region. Our procedure was developed and tested in a large river basin in Finland, providing information from intensively studied eLTER research sites. To evaluate the full GHG balance, fluxes from natural ecosystems (lakes, rivers, and undrained mires) were included together with fluxes from anthropogenic activities, agriculture and forestry. We quantified the fluxes based on calculations with an anthropogenic emissions model (FRES) and a forest growth and carbon balance model (PREBAS), as well as on emission coefficients from the literature regarding emissions from lakes, rivers, undrained mires, peat extraction sites and cropland. Spatial data sources included CORINE land use data, soil map, lake and river shorelines, national forest inventory data, and statistical data on anthropogenic activities. Emission uncertainties were evaluated with Monte Carlo simulations. Artificial surfaces were the most emission intensive land-cover class. Lakes and rivers were about as emission intensive as arable land. Forests were the dominant land cover in the region (66%), and the C sink of the forests decreased the total emissions of the region by 72%. The region's net emissions amounted to 4.37 ± 1.43 Tg CO2-eq yr−1, corresponding to a net emission intensity 0.16 Gg CO2-eq km−2 yr−1, and estimated per capita net emissions of 5.6 Mg CO2-eq yr−1. Our landscape approach opens opportunities to examine the sensitivities of important GHG fluxes to changes in land use and climate, management actions, and mitigation of anthropogenic emissions.

Carbon balance of tropical peat forests at different fire history and implications for carbon emissions.

Accurate assessment of tropical peat forest carbon stocks and impact of fires on carbon pools is required to determine the magnitude of emissions to the atmosphere and to support emissions reduction policies. We assessed total aboveground carbon (AGC) in biomass pools including trees, shrubs, deadwood, litter and char, and peat carbon to develop empirical estimates of peat swamp forest carbon stocks in response to fire and disturbance. In contrast to the common assumption that peat fires combust all AGC, we observed that about half of undisturbed forest AGC, equivalent to about 70Mg C ha-1, remains after one or two recent fires - mainly in dead trees, woody debris and pyrogenic carbon. Both recently burnt and repeatedly burnt peat forests store similar amounts of carbon in the top 10cm of peat when compared with undisturbed forests (70Mg C ha-1), mainly due to increased peat bulk density after fires that compensates for their lower peat C%. The proportion of fuel mass consumed in fire, or combustion factor (CF), is required to make accurate estimates of peat fire emissions for both AGC and peat carbon. This study estimated a CF for AGC (CFAGC) of 0.56, comparable to the default value of the Intergovernmental Panel on Climate Change (IPCC). This study estimated a varying CF for peat (CFPEAT) that ranged from 0.4 to 0.68 as depth of burn increased. This revised CFPEAT is one third to one half of the IPCC default value of 1.0. The current assumption of complete combustion of peat (CF=1.0) is widely acknowledged in the literature as oversimplification and is not supported by our field observations or data. This study provides novel empirical data to improve estimates of peat forests carbon stocks and emissions from tropical peat fires.

Optimizing forest management for climate impact and economic profitability under alternative initial stand age structures

The full climate impacts of forest production and biomass use, and economic profitability of forest biomass production were studied under four alternative initial age structures of a forested landscape (young, even-aged, middle-aged and mature) in boreal conditions over 80 years. The forested landscapes occupied either by Scots pine or Norway spruce were managed by using seven management scenarios. The current thinning recommendations were considered as a baseline and alternative scenarios included maintaining 20% higher or lower stocking than in the baseline. The previous ones were also managed by using N fertilization, and an unthinned scenario (with final felling) was used as a comparison. A life cycle assessment tool with inputs from a forest ecosystem model was used to calculate full climate impacts of forest production and biomass use in substituting fossil-fuel-intensive materials and fossil fuels. The results showed that increased stocking and N fertilization were generally the most optimal forest management scenarios for full climate impacts and economic profitability in both species. Increased carbon sequestration through forest management surpassed the decreased economic profitability, and no single management scenario maximized both climate impact and economic profitability. The lowest climate impact, but the highest economic profitability, was found for the initially mature age structure. The calculated average displacement factors for the harvested wood products served as valid indicators for climate impacts but could not thoroughly depict the absolute climate impacts. More research is needed to improve the dynamic connection between forest ecosystem carbon balances and the substitution effects of harvested wood products.

Restoration Thinning in a Drought‐Prone Idaho Forest Creates a Persistent Carbon Deficit

AbstractWestern US forests represent a carbon sink that contributes to meeting regional and global greenhouse gas targets. Forest thinning is being implemented as a strategy for reducing forest vulnerability to disturbance, including mortality from fire, insects, and drought, as well as protecting human communities. However, the terrestrial carbon balance impacts of thinning remain uncertain across regions, spatiotemporal scales, and treatment types. Continuous and in situ long‐term measurements of partial harvest impacts to stand‐scale carbon and water cycle dynamics are nonetheless rare. Here, we examine post‐thinning carbon and water flux impacts in a young ponderosa pine forest in Northern Idaho. We examine in situ stock and flux impacts during the 3 years after treatment as well as simulate the forest sector carbon balance through 2050, including on and off‐site net emissions. During the observation period, increases in tree‐scale net primary production (NPP) and water use persistence through summer drought did not overcome the impacts of density reduction, leading to 45% annual reductions of NPP. Growth duration remained constrained by summer drought in control and thinned stands. Ecosystem model and life cycle assessment estimates demonstrated a net forest sector carbon deficit relative to control stands of 27.0 Mg C ha−1 in 2050 due to emissions from dead biomass pools despite increases to net ecosystem production. Our results demonstrate dynamics resulting in carbon losses from forest thinning, providing a baseline with which to inform landscape‐scale modeling and assess tradeoffs between harvest losses and potential gains from management practices.

Cumulative effects of natural and anthropogenic disturbances on the forest carbon balance in the oil sands region of Alberta, Canada; a pilot study (1985\u20132012)

BackgroundAssessing cumulative effects of anthropogenic and natural disturbances on forest carbon (C) stocks and fluxes, because of their relevance to climate change, is a requirement of environmental impact assessments (EIAs) in Canada. However, tools have not been developed specifically for these purposes, and in particular for the boreal forest of Canada, so current forest C assessments in EIAs take relatively simple approaches. Here, we demonstrate how an existing tool, the Generic Carbon Budget Model (GCBM), developed for national and international forest C reporting, was used for an assessment of the cumulative effects of anthropogenic and natural disturbances to support EIA requirements. We applied the GCBM to approximately 1.3 million ha of upland forest in a pilot study area of the oil sands region of Alberta that has experienced a large number of anthropogenic (forestry, energy sector) and natural (wildfire, insect) disturbances.ResultsOver the 28 years, 25% of the pilot study area was disturbed. Increasing disturbance emissions, combined with declining net primary productivity and reductions in forest area, changed the study area from a net C sink to a net C source. Forest C stocks changed from 332.2 Mt to 327.5 Mt, declining by 4.7 Mt at an average rate of 0.128 tC ha−1 yr−1. The largest cumulative areas of disturbance were caused by wildfire (139,000 ha), followed by the energy sector (110,000 ha), insects (33,000 ha) and harvesting (31,000 ha) but the largest cumulative disturbance emissions were caused by the energy sector (9.5 Mt C), followed by wildfire (5.5 Mt C), and then harvesting (1.3 Mt C).ConclusionAn existing forest C model was used successfully to provide a rigorous regional cumulative assessment of anthropogenic and natural disturbances on forest C, which meets requirements of EIAs in Canada. The assessment showed the relative importance of disturbances on C emissions in the pilot study area, but their relative importance is expected to change in other parts of the oil sands region because of its diversity in disturbance types, patterns and intensity. Future assessments should include peatland C stocks and fluxes, which could be addressed by using the Canadian Model for Peatlands.

A Methodology for Implementing a Digital Twin of the Earth’s Forests to Match the Requirements of Different User Groups

Europe has acknowledged the need to develop a very high precision digital model of the Earth, a Digital Twin Earth, running on cloud infrastructure to bring data and end-users closer together. We present results of an investigation of a proposed submodel of the digital twin, simulating the worlds’ forests. We focus on the architecture of the system and the key user needs on data content and access. The results are based on a user survey showing that the forest-related communities in Europe require information on contrasting forest variables and processes, with common interest in the status and forecast of forest carbon stock. We discuss the required spatial resolution, accuracies, and modelling tools required to match the needs of the different communities in data availability and simulation of the forest ecosystem. This, together with the knowledge on existing and projected future capabilities, allows us to specify a data architecture to implement the proposed system regionally, with the outlook to expand to continental and global scales. Ultimately, a system simulating the behaviour of forests, a digital twin, would connect the bottom-up and top-down approaches of computing the forest carbon balance: from tree-based accounting of forest growth to atmospheric measurements, respectively.