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Harvard Forest Data Archive

HF430

Belowground Carbon Observatory Network (BeCON) at Harvard Forest since 2020

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Data

Overview

  • Lead: Adrien Finzi
  • Investigators: Marc-Andre Giasson
  • Contact: Information Manager
  • Start date: 2020
  • End date: 2021
  • Status: ongoing
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.54 degrees
  • Longitude: -72.17 degrees
  • Elevation: 340 meter
  • Datum: WGS84
  • Taxa: Quercus rubra (red oak), Tsuga canadensis (eastern hemlock)
  • Release date: 2023
  • Language: English
  • EML file: knb-lter-hfr.430.2
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: long-term measurement
  • Research topic: soil carbon and nitrogen dynamics
  • LTER core area: organic matter movement
  • Keywords: biomass, carbon, hemlock, nitrogen, oak, production, roots, soil carbon, soil water content
  • Abstract:

    A central goal of the recent Harvard Forest C Synthesis activity was to identify high-priority needs for C-cycle research at the forest. While there were a number of areas needing follow-up research, belowground C pools and fluxes remain the single largest gap in the C budget and therefore our understanding of the C cycle of the forest. To this end, we developed the Belowground Carbon Observatory Network (BeCON) as a part of the LTER-VI grant proposal.

    The long-term goal of BeCON is to understand temporal and spatial variations in belowground C pools in response to the various environmental changes the forest now faces [e.g., rising CO2, changes in atmospheric N, S and O3 chemistry, invading insects, land-use change, immigrating (large) herbivores]. There are two great challenges in achieving this goal: (1) excessive spatial heterogeneity in belowground C pools; and (2) lack of automated systems for analysis. These characteristics make it very difficult to quantify changes because the work is intrinsically labor intensive with low replication and the noisy data lead to low statistical power.

    Here, we measured soil carbon content, root biomass and carbon content, and annual root productivity following the protocols for BeCON.

  • Methods:

    Conant plots

    Each plot used the 2 m × 5 m “Conant” design (Figure 1 in Conant et al. 2003 [Conant, R.T., Smith, G.R., Paustian, K. 2003. Spatial Variability of Soil Carbon in Forested and Cultivated Sites: Implications for Change Detection. J. Environ. Qual. 32:278–286.]) with six subplots. In each subplot, we collected a 10 cm × 10 cm organic horizon sample and then sampled the underlying mineral soil to a depth of 30 cm in 10 cm increments. The soil core was 4.7cm diameter.

    Soil carbon and root biomass

    Samples were brought to Boston University and kept refrigerated at 4°C until being processed. Samples were homogenized by sieving through 2-mm mesh and removing rocks and woody debris. At the same time, roots were picked and set aside.

    Subsamples of the sieved soils were dried at 60°C for at least 48 hours to determine soil gravimetric water content. The dry soil was later ground to a fine powder and burned in an elemental analyzer (model NC2500, CE Elantech) to determine carbon and nitrogen content.

    Roots were washed with deionized water and sorted into dead and live root pools according to their diameter (fine: less than 2mm, medium: 2–10mm, coarse: more than 10mm). Roots were then dried at 60°C until weight was stable (at least 48 hours). Dry root biomass was recorded. Note that the separation of roots between live and dead categories can be very subjective at times and mistakes have likely happened.

    In theory, all mineral soil samples should be 10cm thick (0–10cm, 10–20cm, 20–30cm). In practice, some samples are smaller than that or altogether missing, generally because we hit a large rock during sampling. The actual thickness of each sample is listed in the column labelled “thickness”.

    Root ingrowth cores

    In May 2021, we installed two root ingrowth cores in the mineral soil to complement the Conant plots at each of the EMS biometry plots. At the same time, we installed the same number of shorter ingrowth cores in the organic horizon.

    The 30 cm-long ingrowth cores were 5 cm in diameter and consisted of a PVC frame covered with 1-mm fiberglass mesh. The 30 cm cores were filled with homogenized root-free mineral soil packed at the approximate bulk density. They were inserted in the top 30 cm of the mineral soil. Shorter cores (15 cm) made of the same PVC frame and 1-mm fiberglass mesh were filled with root-free organic horizon soil packed to the approximate bulk density. Cores were inserted vertically in the soil, and the shorter organic horizon ones were packed until their content was flush with the soil surface. The mineral and organic soil cores were inserted near, but not on top of, each other.

    All cores were collected in October 2021. Roots that grew in the core were collected, dried, and weighed to estimate fine root production, and ground to a fine powder and run on an elemental analyzer to measure N and C content.

    Plot location

    To help with locating plots, please consult file hf430-06-conant-plots.pdf

  • Organization: Harvard Forest. 324 North Main Street, Petersham, MA 01366, USA. Phone (978) 724-3302. Fax (978) 724-3595.

  • Project: The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts. (ROR).

  • Funding: National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210. Other funding: NSF grants DEB-1749206 and DEB-1456528; DOE Joint Genome Institute Contract No. DE-AC02-05CH11231.

  • Use: This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.

  • License: Creative Commons Zero v1.0 Universal (CC0-1.0)

  • Citation: Finzi A. 2023. Belowground Carbon Observatory Network (BeCON) at Harvard Forest since 2020. Harvard Forest Data Archive: HF430 (v.2). Environmental Data Initiative: https://doi.org/10.6073/pasta/196c572062085cf760f935c13bfacca7.

Detailed Metadata

hf430-01: dry root biomass

  1. date: sampling date (date of 2020-09-15 indicates roots collected between August and October of 2020)
  2. plot: plot number
  3. subplot: subplot number
  4. depth: depth
    • OH: organic horizon
    • 0-10cm: 0-10 cm in the mineral soil
    • 10-20cm: 10-20 cm in the mineral soil
    • 20-30cm: 20-30 cm in the mineral soil
  5. thickness: sample thickness (unit: centimeter / missing value: NA)
  6. live.fine.mass: dry mass of live roots, diameter less than 2 mm (unit: gram / missing value: NA)
  7. live.medium.mass: dry mass of live roots, diameter 2-10 mm (unit: gram / missing value: NA)
  8. live.coarse.mass: dry mass of live roots, diameter greater than 10 mm (unit: gram / missing value: NA)
  9. dead.fine.mass: dry mass of dead roots, diameter less than 2 mm (unit: gram / missing value: NA)
  10. dead.medium.mass: dry mass of dead roots, diameter 2-10 mm (unit: gram / missing value: NA)
  11. dead.coarse.mass: dry mass of dead roots, diameter greater than 10 mm (unit: gram / missing value: NA)
  12. notes: notes

hf430-02: soil moisture and bulk density

  1. date: sampling date (date of 2020-09-15 indicates roots collected between August and October of 2020)
  2. plot: plot number
  3. subplot: subplot number
  4. depth: depth
    • OH: organic horizon
    • 0-10cm: 0-10 cm in the mineral soil
    • 10-20cm: 10-20 cm in the mineral soil
    • 20-30cm: 20-30 cm in the mineral soil
  5. thickness: sample thickness (unit: centimeter / missing value: NA)
  6. soil_mass: soil mass, including rocks (unit: gram / missing value: NA)
  7. rock_mass: mass of rocks greater than 2mm in sample (unit: gram / missing value: NA)
  8. dry_wet_ratio: ratio of dry and wet mass of soil (unit: dimensionless / missing value: NA)
  9. moisture_content: water content of the sample (%) (unit: dimensionless / missing value: NA)
  10. bulk_density: bulk density of the sample (unit: gramsPerCubicCentimeter / missing value: NA)
  11. notes: notes

hf430-03: ingrowth cores dry root biomass and C N

  1. installation_date: date the core was inserted in the ground
  2. removal_date: date the core was retrieved from the ground
  3. plot: plot number
  4. core: core number
  5. depth: depth
    • OH: organic horizon
    • 0-10cm: 0-10 cm in the mineral soil
    • 10-20cm: 10-20 cm in the mineral soil
    • 20-30cm: 20-30 cm in the mineral soil
  6. dry_root_mass: dry mass of roots found in the core (unit: gram / missing value: NA)
  7. percent_N: nitrogen content of the roots (%) (unit: dimensionless / missing value: NA)
  8. percent_C: carbon content of the roots (%) (unit: dimensionless / missing value: NA)
  9. notes: notes

hf430-04: root carbon and nitrogen content

  1. plot: plot number
  2. subplot: subplot number
  3. depth: depth
    • OH: organic horizon
    • 0-10cm: 0-10 cm in the mineral soil
    • 10-20cm: 10-20 cm in the mineral soil
    • 20-30cm: 20-30 cm in the mineral soil
  4. live_or_dead: were the roots alive or dead at the time of sampling
    • Dead: dead
    • Live: alive
  5. root_diameter: diameter of the roots
  6. percent_N: nitrogen content of the roots (%) (unit: dimensionless / missing value: NA)
  7. percent_C: carbon content of the roots (%) (unit: dimensionless / missing value: NA)

hf430-05: soil carbon and nitrogen content

  1. plot: plot number
  2. subplot: subplot number
  3. depth: depth
    • OH: organic horizon
    • 0-10cm: 0-10 cm in the mineral soil
    • 10-20cm: 10-20 cm in the mineral soil
    • 20-30cm: 20-30 cm in the mineral soil
  4. percent_N: nitrogen content of the soil (%) (unit: dimensionless / missing value: NA)
  5. percent_C: carbon content of the soil (%) (unit: dimensionless / missing value: NA)

hf430-06: plot location guide

  • Compression: none
  • Format: pdf
  • Type: document