DOI: 10.5061/dryad.dv41ns267
title: Boreal conifer swamp carbon stocks and fluxes, Alberta, Canada

description: The carbon (C) dynamics of boreal coniferous swamps are a largely
 understudied component of wetland carbon cycling. We investigated the
 above- and below-ground carbon stocks and growing season carbon dioxide
 (CO2) and methane (CH4) fluxes from a representative boreal coniferous
 swamp in northern Alberta, Canada in 2022. Tree inventories, understory
 vegetation biomass, and peat cores were collected across three sub-sites
 within the broader swamp, with gas flux collars placed in the dominant
 plant communities present. Alongside the C flux measurements,
 environmental variables such as water table depth, soil temperature, and
 growing season understory green leaf phenology were measured. Our results
 show that these boreal coniferous swamps store large volumes of organic C
 in their biomass and soil (134 kg C m-2), comparable with other wetland
 and forest types, although 95% of the total C stock at our site was within
 the soil organic carbon. We also found that understory CO2 and CH4 fluxes
 indicated that the ground layer of the site is a source of greenhouse
 gases (GHG) to the atmosphere across the growing season. However, we did
 not measure litterfall input, tree GHG fluxes or net primary productivity
 of the overstory, therefore we are not able to say whether the site is an
 overall source of C to the atmosphere. This study provides a much-needed
 insight into the C dynamics of these under-valued wetland ecosystems, and
 we highlight the need for a coordinated effort across boreal regions to
 try to improve inventories of C stocks and fluxes.
description: # Boreal conifer swamp carbon stocks and fluxes, Alberta, Canada Dataset
 DOI: [10.5061/dryad.dv41ns267](https://doi.org/10.5061/dryad.dv41ns267) ##
 Description of the data and file structure This dataset contains field
 measurements and laboratory analyses from **Heaven Swamp**, a boreal
 coniferous swamp in northern Alberta, Canada (56°57′28″N, 111°33′24″W).
 Data were collected during the 2022 growing season to quantify vegetation
 composition, tree biomass, peat characteristics, and greenhouse gas (CO₂
 and CH₄) fluxes. **Study design** * Three 10 × 10 m plots (HS-1, HS-2,
 HS-3). * Measurements collected from vegetation plots, tree measurements,
 soil/peat cores, and gas flux collars installed in two dominant vegetation
 communities (feather moss and Sphagnum) ### Files and variables #### File:
 Davidson_et_al_boreal_swamp_carbon_clean.xlsx **Description:**  #####
 Variables | Sheet | Column | Description | | :---------------------------
 | :------------------------------------------------------ |
 :-------------------------------------------------------------------------------------- | | CO2 CH4 flux and enviro data | DATE | Date of chamber gas flux measurement. | | CO2 CH4 flux and enviro data | PEATLAND TYPE | Vegetation community (Sphagnum or feather moss). | | CO2 CH4 flux and enviro data | SITE | Name of swamp | | CO2 CH4 flux and enviro data | COLLAR ID | Unique ID for each gas flux collar. | | CO2 CH4 flux and enviro data | VEGETATION TYPE | Vegetation type inside collar (vegetated or clipped). | | CO2 CH4 flux and enviro data | NET ECOSYSTEM EXCHANGE (g CO2 m-2 d-1) | Net CO2 flux (negative = uptake; positive = emission). | | CO2 CH4 flux and enviro data | ECOSYSTEM RESPIRATION (g CO2 m-2 d-1) | CO2 released in dark chamber conditions. | | CO2 CH4 flux and enviro data | GROSS ECOSYSTEM PRODUCTIVITY (g CO2 m-2 d-1) | Plant CO2 uptake (NEE - ER). | | CO2 CH4 flux and enviro data | METHANE FLUX (mg CH4 m-2 d-1) | CH4 flux (positive = emission). | | CO2 CH4 flux and enviro data | WATER TABLE DEPTH (cm) | Depth to water table (cm) relative to ground surface. | | CO2 CH4 flux and enviro data | SOIL TEMPERATURE AT 2, 5, 10, 15, 20, 25 or 30 CM DEPTH | Soil temperature measured at each depth (degrees C). | | CO2 CH4 flux and enviro data | GREEN CHROMATIC COORDINATE | Greenness data extracted from digital photographs | | Soil Properties | CORE NO | Peat core identifier. | | Soil Properties | UPPER/MID/LOWER DEPTH (cm) | Depth interval (cm) represented by subsample | | Soil properties | DRY WEIGHT (g) | Weight of soil sample after being dried in oven | | Soil properties | SAMPLE VOLUME (g cm-3) | Volume of sample analysed | | Soil Properties | DRY BULK DENSITY (g cm-3) | Dry peat density  | | Soil Properties | ORGANIC MATTER CONTENT (%) | % organic matter from loss-on-ignition. | | Soil Properties | TOTAL CARBON (%) | Carbon concentration of subsample (%). | | Soil Properties | TOTAL NITROGEN (%) | Nitrogen concentration of subsample (%). | | Soil Properties | d^13^C (‰) | Ratio of heavy to light carbon isotopes (¹³C/¹²C) in soil sample compared to a standard | | Soil Properties | d^15^N (‰) | Ratio of heavy to light nitrogen isotopes (¹⁵N/¹⁴N) in a sample compared to a standard | | Peat Depth | DATE | Date of soil core sampling | | Peat Depth | SITE NO | Plot identifier (Site 1, 2 or 3). | | Peat Depth | LOCATION | Location within plot | | Peat Depth | DEPTH | Peat depth measurements (cm). | | Understory Biomass | DATE | Date of vegetation sampling | | Understory Biomass | SITE | Plot identifier (Site 1, 2 or 3). | | Understory Biomass | GROUP | Plant Functional Group | | Understory Biomass | FRESH WEIGHT | Wet mass of vegetation (g). | | Understory Biomass | DRY WEIGHT | Dry mass of vegetation (g). | | Understory Biomass | PLOT AREA | Size of area sampled (0.0625 m2) | | Tree Measurements | DATE | Date of tree survey | | Tree Measurements | SITE NO | Plot identifier (Site 1, 2 or 3). | | Tree Measurements | CATEGORY | Tall (&gt;1.6 m) or short (&lt;1.6 m) tree class. | | Tree Measurements | SPECIES | Species name (e.g., Picea mariana). | | Tree Measurements | CIRCUMFERENCE | Stem circumference at breast height (cm). | | Tree Measurements | HEIGHT | Tree height (cm) | NA in data sheets means there was no data available or no data applicable depending on sheet. ## Access information Data was derived from the following sources: **Davidson, S.J.**, Davies, M.A., Wegener, E., Claussen, S., Schmidt, M., Peacock, M. and Strack, M. (2024) **Carbon stocks and fluxes from a boreal conifer swamp: filling a knowledge gap for understanding the boreal C cycle** *JGR Biogeosciences* 129(5): e2024JG008005 **[https://doi.org/10.1029/2024JG008005](https://doi.org/10.1029/2024JG008005)**