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Peatlands cover approximately 12% of the Canadian landscape and play an important role in the carbon cycle through their centennial‐ to millennial‐scale storage of carbon under waterlogged and anoxic conditions. In recognizing the potential of these ecosystems as natural climate solutions and therefore the need to include them in national greenhouse gas inventories, the Canadian Model for Peatlands module (CaMP v. 2.0) was developed by the Canadian Forest Service. Model parameterization included compiling peat profiles across Canada to calibrate peat decomposition rates from different peatland types, to define typical bulk density profiles, and to describe the hydrological (i.e., water table) response of peatlands to climatic changes. A total of 1217 sites were included in the dataset from published and unpublished sources. The CORESITES table contains site location and summary data for each profile, as well as an estimate of total carbon mass per unit area (in megagrams of C per hectare). Total carbon mass per unit area at each location was calculated using bulk density and carbon content through each profile. The PROFILES table contains data for depth (in centimeters), bulk density (in grams per cubic meter), ash and carbon content (in percentage), and material descriptions for contiguous samples through each peat profile. Data gaps for bulk density and C content were filled using interpolation, regression trees, and assigned values based on material description and/or soil classification to allow for the estimation of total carbon mass per unit area. A subset of the sites (N = 374) also have pH and pore water trace‐elemental geochemistry data and are found in the WATER table. The REFERENCES table contains the full citation of each source of the data and is linked to each core location through the SOURCEDATA table. The LOOKUP table defines codes in the database that required more space that what was sufficient in the metadata tables. The data can be accessed on Open Government Canada and will be useful for future work on carbon stock mapping and ecosystem modeling. All metadata and data are provided © Her Majesty the Queen in Right of Canada, 2023 and information contained in this publication may be reproduced for personal or public noncommercial purposes with attribution, whereas commercial reproduction and distribution are prohibited except with written permission from NRCan; complete details are noted in the Supporting Information file Metadata S1 (see Class III.B.3: Copyright restrictions). [ABSTRACT FROM AUTHOR]

Mosses play a key role in the carbon (C) cycle of upland black spruce (Picea mariana (Mill.) BSP) forests; however, national reporting models such as the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) do not include mosses. This study examined whether widely available plot-level merchantable tree volume could predict, for black spruce ecosystems in Canada's boreal forest, the relative proportions of sphagnum and feather moss ground cover and moss net primary productivity (NPP). A field study found that merchantable tree volume was significantly related to tree canopy openness ([R.sup.2] = 0.61, P < 0.001), which could then be used to model the relative ground cover of feather moss ([R.sup.2] = 0.5, P < 0.001) and sphagnum ([R.sup.2] = 0.45, P < 0.001) and NPP of feather moss ([R.sup.2] = 0.41, P < 0.001) and sphagnum ([R.sup.2] = 0.28, P < 0.001). The resulting MOSS-C submodel increased the accuracy of the CBM-CFS3's prediction of organic-horizon C five-fold and could explain large-scale variation in sites dominated by sphagnum with large organic layer C pools but not fine-scale variation in dryer sites. To improve MOSS-C accuracy, future studies should focus on varying decomposition and fire regime parameters based on regional climate or plot-level vegetation parameters. Key words: moss carbon, carbon model, black spruce, sphagnum, feather moss. Les mousses jouent un role cle dans le cycle du carbone (C) des forets d'epinette noire (Picea mariana (Mill.) BSP). Toutefois, les modeles a l'echelle nationale, comme le modele du bilan du carbone du Secteur forestier canadien (MBC-SFC3), n'incluent pas les mousses. Cette etude vise a determiner si les donnees largement disponibles de volume marchand des arbres a l'echelle de la placette peuvent predire les proportions relatives du couvert de sphaignes et de mousses hypnacees ainsi que la productivite primaire nette (PPN) des mousses dans les ecosystemes d'epinette noire de la foret boreale canadienne. Une etude de terrain a montre que le volume marchand des arbres etait significativement relie a l'ouverture du couvert dominant ([R.sup.2] = 0,61, P Mots-cles: carbone des mousses, modele de carbone, epinette noire, sphaignes, mousses hypnacees., Introduction The boreal biome contains approximately 40% of the global terrestrial pool of carbon (C) (McGuire et al. 2001). In Canada, black spruce (Picea mariana (Mill.) BSP) forests are very [...]

Renewal of pine forests is ecologically dependent on fires, but if fires become too frequent, they can disrupt the equilibrium and sustainability of these ecosystems. Field studies of the effects of fire are challenging because of the heterogeneity of forest ecosystems and because of the heterogeneous effect of fire on recovery of vegetation. As an alternative to complex field studies, mathematical models can be used as a tool to assess the complex dynamics of natural ecosystems as they recover after fire. The aim of this study was to apply the ecosystem model EFIMOD to analyse the effect of surface fires on soil degradation and its feedback on tree productivity in Scots pine forests on different soil types in Russia: Haplic Podzols in the Leningrad region and Psamment Entisols of the fragmented steppe in the Samara region. Simulation of the cumulative effects of fire cycles over 140 years showed that one fire did not affect growing stock but decreased soil organic matter by about 10% at both sites, and that three fires reduced the growing stock by 30% on the Haplic Podzols and 9% on the Psamment Entisols and decreased soil organic matter by about 30% on both sites. Forest fires led to the loss of soil carbon (C), as well as nitrogen (N), which is a principal limiting factor in forest ecosystems of boreal and temperate ecozones. The effect of repeated fire cycles on land degradation is similar to that of soil erosion, through the loss of soil C and N. [ABSTRACT FROM AUTHOR]

Abstract: In the inland temperate rainforests (ITRs) of east-central British Columbia (BC), there is a lack of baseline carbon (C) stocks information for managed and unmanaged stands of old-growth western redcedar and hemlock. To fill the knowledge gap, we estimated C stocks of live trees, snags, coarse woody debris and forest floor (excluding mineral soil) and evaluated impacts of harvesting on these C stocks. We also accounted for heart-rot in stem wood of live cedar and hemlock, and identified uncertainties in live-tree C stocks estimation for more accurate assessment of the C. Forests stands were selected from three previously established silvicultural systems trials that contrasted three levels of harvesting intensity (clear-cut (CC, 0% retention), group retention (GR, 30%), group selection (GS, 70%)), and uncut old-growth (100%). Despite a high incidence of heart-rot, live-tree and total forest (minus mineral soil) C stocks (348±155 and 455±156Mg C ha−1, respectively) in uncut old-growth ITR stands were within the range of regional averages for old-growth forests in the Pacific Northwest (US) and coastal cedar and hemlocks forests of BC. Intensive harvesting (CC and GR) resulted in significant reductions in total forest C stocks (78% and 64%) relative to uncut old-growth stands. By contrast, total forest C stocks in stands where high-retention harvesting (GS) occurred were reduced by only 13% (not significant) relative to uncut old-growth stands. Analysis of uncertainty identified allometric equations to be the largest contributor to total uncertainty in live-tree C stocks, indicating the need to develop more robust equations to reduce the uncertainty for more accurate evaluation of harvesting impacts in old ITRs. Although heart-rot had no significant effects on forest C stocks in this study, we need a better scientific understanding of their contribution to live-tree C in this ecosystem. Nonetheless, these results underscore the importance of conserving C-rich old ITRs where possible and the potential for high-retention harvesting to maintain C stocks in this forest type. [Copyright &y& Elsevier]

Understanding the effects of disturbance regimes on carbon (C) stocks and stock changes is a prerequisite to estimating forest C stocks and fluxes. Live-tree, dead-tree, woody debris (WD), stump, buried wood, organic layer, and mineral soil C stock data were collected from high-boreal black spruce (Picea mariana (Mill.) B.S.P.) stands of harvest and fire origin and compared to values predicted by the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3); the core model of Canada's National Forest Carbon Monitoring, Accounting and Reporting System. Data comparing the effect of natural and anthropogenic disturbance history on forest C stocks are limited, but needed to evaluate models such as the CBM-CFS3. Results showed that adjustments to the CBM-CFS3 volume-to-biomass conversion and partitioning parameters were required for the non-merchantable and branch C pools to accurately capture live-tree C stocks in the studied black spruce ecosystems. Accuracy of the CBM-CFS3 modelled estimates of dead organic matter and soil C pools was improved relative to regional default parameters by increased snag fall and >10cm WD base decay rates. The model evaluation process also highlighted the importance of developing a bryophyte module to account for bryophyte C dynamics and the physical burial of woody debris by bryophytes. Modelled mineral soil C estimates were improved by applying a preliminary belowground slow C pool base decay rate optimized for the soil type of the studied sites, Humo-Ferric Podzols. [Copyright &y& Elsevier]