uid=HFR,o=lter,dc=ecoinformatics,dc=org all public read doi:10.6073/pasta/196c572062085cf760f935c13bfacca7 Adrien Finzi https://orcid.org/0000-0003-2220-4533 Marc-Andre Giasson Researcher 2023 English

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.

biomass carbon hemlock nitrogen oak production roots soil carbon soil water content LTER controlled vocabulary organic matter LTER core area Harvard Forest HFR LTER USA HFR default

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.

Creative Commons Zero v1.0 Universal https://spdx.org/licenses/CC0-1.0.html CC0-1.0 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf430 Prospect Hill Tract (Harvard Forest). Coordinates based on WGS84 datum. -72.17 -72.17 +42.54 +42.54 340 340 meter 2020 2021 genus Quercus species rubra red oak genus Tsuga species canadensis eastern hemlock ongoing Information Manager Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 hf-im@lists.fas.harvard.edu Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu

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.

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”.

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.

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

Harvard Forest

324 North Main Street Petersham MA 01366 USA

(978) 724-3302 (978) 724-3595 https://harvardforest.fas.harvard.edu https://ror.org/059cpzx98 pointOfContact 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. 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. hf430-01-root-biomass.csv dry root biomass hf430-01-root-biomass.csv 15091 e9e5f7fdd2361e9ecff35936c607e5ed 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-01-root-biomass.csv date sampling date (date of 2020-09-15 indicates roots collected between August and October of 2020) YYYY-MM-DD 1 day NA missing value plot plot number plot number NA missing value subplot subplot number subplot number NA missing value 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 NA missing value thickness sample thickness centimeter 0.01 real NA missing value live.fine.mass dry mass of live roots, diameter less than 2 mm gram 0.01 real NA missing value live.medium.mass dry mass of live roots, diameter 2-10 mm gram 0.01 real NA missing value live.coarse.mass dry mass of live roots, diameter greater than 10 mm gram 0.01 real NA missing value dead.fine.mass dry mass of dead roots, diameter less than 2 mm gram 0.01 real NA missing value dead.medium.mass dry mass of dead roots, diameter 2-10 mm gram 0.01 real NA missing value dead.coarse.mass dry mass of dead roots, diameter greater than 10 mm gram 0.01 real NA missing value notes notes notes 270 hf430-02-soil-moisture-density.csv soil moisture and bulk density hf430-02-soil-moisture-density.csv 15335 53b1fc10d018cd8a8389a10158ed3db0 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-02-soil-moisture-density.csv date sampling date (date of 2020-09-15 indicates roots collected between August and October of 2020) YYYY-MM-DD 1 day NA missing value plot plot number plot number NA missing value subplot subplot number subplot number NA missing value 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 NA missing value thickness sample thickness centimeter 0.01 real NA missing value soil_mass soil mass, including rocks gram 0.01 real NA missing value rock_mass mass of rocks greater than 2mm in sample gram 0.01 real NA missing value dry_wet_ratio ratio of dry and wet mass of soil dimensionless 0.0001 real NA missing value moisture_content water content of the sample (%) dimensionless 0.01 real NA missing value bulk_density bulk density of the sample gramsPerCubicCentimeter 0.01 real NA missing value notes notes notes 270 hf430-03-ingrowth-cores-cn.csv ingrowth cores dry root biomass and C N hf430-03-ingrowth-cores-cn.csv 17946 2197c5217eaa76eba2ae23ae535e57ad 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-03-ingrowth-cores-cn.csv installation_date date the core was inserted in the ground YYYY-MM-DD 1 day NA missing value removal_date date the core was retrieved from the ground YYYY-MM-DD 1 day NA missing value plot plot number plot number NA missing value core core number core number NA missing value 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 NA missing value dry_root_mass dry mass of roots found in the core gram 0.01 real NA missing value percent_N nitrogen content of the roots (%) dimensionless 0.00001 real NA missing value percent_C carbon content of the roots (%) dimensionless 0.00001 real NA missing value notes notes notes 264 hf430-04-root-cn.csv root carbon and nitrogen content hf430-04-root-cn.csv 12509 1bfcc2b4e42a399d0f4a485788acc422 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-04-root-cn.csv plot plot number plot number NA missing value subplot subplot number subplot number NA missing value 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 NA missing value live_or_dead were the roots alive or dead at the time of sampling Dead dead Live alive NA missing value root_diameter diameter of the roots diameter of the roots percent_N nitrogen content of the roots (%) dimensionless 0.00001 real NA missing value percent_C carbon content of the roots (%) dimensionless 0.00001 real NA missing value 270 hf430-05-soil-cn.csv soil carbon and nitrogen content hf430-05-soil-cn.csv 9292 dfc437df388b32667890576feef70929 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-05-soil-cn.csv plot plot number plot number NA missing value subplot subplot number subplot number NA missing value 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 NA missing value percent_N nitrogen content of the soil (%) dimensionless 0.00001 real NA missing value percent_C carbon content of the soil (%) dimensionless 0.00001 real NA missing value 270 hf430-06-plots.pdf plot location guide hf430-06-plots.pdf 247264 96da25013daea552465f73540d130999 none pdf https://harvardforest.fas.harvard.edu/data/p43/hf430/hf430-06-plots.pdf document soil long-term measurement https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=HF069