Barre Woods Soil Warming Experiment at Harvard Forest since 2001

<para>Two of the major results of our original soil warming study were that: (1) warming stimulated the decay of a labile soil carbon pool; and (2) it also increased the availability of inorganic nitrogen to plants. Because of the small size of the original warming plots an important question we have not been able to answer conclusively is: Has the increase in available nitrogen led to an increase in carbon storage in the vegetation? And if yes, how much? In a systems context an additional question is: What is the balance between the carbon lost from the soil and the carbon stored in the vegetation in response to soil warming?</para> <para>We are now addressing these important questions with a new warming experiment in the Barre Woods area of the Harvard Forest. The Barre Woods site was chosen because of its similarities to the Prospect Hill site - stand age, tree species composition, and soil type. There is no evidence of a plow horizon at the Barre Woods site, though surrounding stone walls indicate past use as pastureland. Historical records indicate the site was destroyed during the 1938 hurricane and then regrew naturally.</para> <para>During the summer and fall of 2001 we buried 3.4 miles of heating cable in a 30 x 30m plot. Cables were buried at a 10cm depth, spaced 20cm apart. A second 30 x 30m area was delineated to serve as the control plot. Results from the original soil warming experiment confirmed that the soil disturbance associated with the installation of heating cables has had no effect on soil temperatures and only minor and variable impacts on soil moisture.</para> <para>In April 2002, we began a one-year period of baseline measurements before turning on the heat in the new megaplot. These measurements included nitrogen mineralization, trace gas fluxes (CO2, CH4, N2O), tree growth (dendrometer bands), an understory species survey, canopy foliage analysis (C:N, NIR), and lysimetry. Thermistors were installed in both plots to begin tracking soil temperatures. The baseline measurements have confirmed that there are no significant differences between the two plots for key ecosystem processes prior to the initiation of the warming manipulation.</para> <para>We will turn on the power in April 2003 to begin the "manipulation phase" of this study. From this study, we expect to determine whether or not warming results in the movement of nitrogen from the soil to the trees and to learn how this movement affects the net carbon balance of the ecosystem.</para> </section> </abstract> <keywordSet> <keyword>carbon</keyword> <keyword>carbon dioxide</keyword> <keyword>climate change</keyword> <keyword>methane</keyword> <keyword>nitrogen</keyword> <keyword>nitrogen mineralization</keyword> <keyword>nitrous oxide</keyword> <keyword>soil moisture</keyword> <keyword>soil respiration</keyword> <keyword>soil temperature</keyword> <keyword>soil warming</keyword> <keywordThesaurus>LTER controlled vocabulary</keywordThesaurus> </keywordSet> <keywordSet> <keyword>inorganic nutrients</keyword> <keyword>disturbance</keyword> <keywordThesaurus>LTER core area</keywordThesaurus> </keywordSet> <keywordSet> <keyword>Harvard Forest</keyword> <keyword>HFR</keyword> <keyword>LTER</keyword> <keyword>USA</keyword> <keywordThesaurus>HFR default</keywordThesaurus> </keywordSet> <intellectualRights> <section> <para>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.</para> </section> </intellectualRights> <licensed> <licenseName>Creative Commons Zero v1.0 Universal</licenseName> <url>https://spdx.org/licenses/CC0-1.0.html</url> <identifier>CC0-1.0</identifier> </licensed> <distribution> <online> <url function="information">https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf018</url> </online> </distribution> <coverage> <geographicCoverage> <geographicDescription>Slab City Tract (Harvard Forest). Coordinates based on WGS84 datum.</geographicDescription> <boundingCoordinates> <westBoundingCoordinate>-72.18</westBoundingCoordinate> <eastBoundingCoordinate>-72.18</eastBoundingCoordinate> <northBoundingCoordinate>+42.48</northBoundingCoordinate> <southBoundingCoordinate>+42.48</southBoundingCoordinate> </boundingCoordinates> </geographicCoverage> <temporalCoverage> <rangeOfDates> <beginDate> <calendarDate>2001</calendarDate> </beginDate> <endDate> <calendarDate>2024</calendarDate> </endDate> </rangeOfDates> </temporalCoverage> <taxonomicCoverage> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Acer</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>rubrum</taxonRankValue> <commonName>red maple</commonName> </taxonomicClassification> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>saccharum</taxonRankValue> <commonName>sugar maple</commonName> </taxonomicClassification> </taxonomicClassification> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Betula</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>alleghaniensis</taxonRankValue> <commonName>yellow birch</commonName> </taxonomicClassification> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>lenta</taxonRankValue> <commonName>black birch</commonName> </taxonomicClassification> </taxonomicClassification> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Fraxinus</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>americana</taxonRankValue> <commonName>white ash</commonName> </taxonomicClassification> </taxonomicClassification> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Pinus</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>strobus</taxonRankValue> <commonName>white pine</commonName> </taxonomicClassification> </taxonomicClassification> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Quercus</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>rubra</taxonRankValue> <commonName>red oak</commonName> </taxonomicClassification> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>velutina</taxonRankValue> <commonName>black oak</commonName> </taxonomicClassification> </taxonomicClassification> <taxonomicClassification> <taxonRankName>genus</taxonRankName> <taxonRankValue>Tsuga</taxonRankValue> <taxonomicClassification> <taxonRankName>species</taxonRankName> <taxonRankValue>canadensis</taxonRankValue> <commonName>hemlock</commonName> </taxonomicClassification> </taxonomicClassification> </taxonomicCoverage> </coverage> <maintenance> <description> <para>ongoing</para> </description> </maintenance> <contact scope="document"> <positionName>Information Manager</positionName> <organizationName>Harvard Forest</organizationName> <address scope="document"> <deliveryPoint>324 North Main Street</deliveryPoint> <city>Petersham</city> <administrativeArea>MA</administrativeArea> <postalCode>01366</postalCode> <country>USA</country> </address> <phone phonetype="voice">(978) 724-3302</phone> <electronicMailAddress>hf-im@lists.fas.harvard.edu</electronicMailAddress> </contact> <publisher scope="document"> <organizationName>Harvard Forest</organizationName> <address scope="document"> <deliveryPoint>324 North Main Street</deliveryPoint> <city>Petersham</city> <administrativeArea>MA</administrativeArea> <postalCode>01366</postalCode> <country>USA</country> </address> <phone phonetype="voice">(978) 724-3302</phone> <phone phonetype="fax">(978) 724-3595</phone> <onlineUrl>https://harvardforest.fas.harvard.edu</onlineUrl> </publisher> <methods> <methodStep> <description> <section> <title/> <para>The soil in the heated plot was warmed using the buried heating cable method. Heated and control plot temperatures were evaluated on 10 minute intervals by a datalogger, and the heating cables turned on or off accordingly to maintain a difference between the heated and control plot of 5 degrees C. Heated and control plot temperature moisture were recorded on four hour intervals from 2003-2008, and on hourly intervals from 2009 on.</para> <para>Soil respiration was measured by placing chamber lids over permanent collars installed in the plots for 15 minutes and sampling the headspace gas at 5 minute intervals. CO2 was measured for the duration of the experiment to date, and CH4 and N2O were measured from 2003-2007. CO2 sample concentrations were measured with an infrared gas analyzer, and CH4 and NO2 sample concentrations were measured by gas chromatography. Fluxes were calculated based on the changes in concentrations over the incubation period. Soil temperatures were measured at 2 and 4cm at the time of each gas sampling. Soil moisture measurements were conducted using gravimetric techniques for the first year of the study and by automated time domain reflectometry (TDR) starting in 2003.</para> <para>Net N mineralization and nitrification were measured for the forest floor and mineral soil using an on-site buried bag incubation. Incubations were for 5 weeks, April- November, and for 5 months through the winter. Initial samples were collected and analyzed for extractable (2N KCl, 48 hours) NH4+ and NO3- content. The same analysis was carried out on the incubated samples. The difference in total mineral N content between initial and incubated soils is the net mineralization rate.</para> <para>Concentrations of inorganic N in water leaching below the rooting zone were measured using high-tension lysimetry. Soil water samples were collected from 6 porous cup lysimeters per plot, monthly, although in some months no sample was recovered from some or all lysimeters. Lysimeters were installed at a depth of 50 cm and evacuated to ~15 in Hg 24 h before sampling. Samples were frozen until they were analyzed for NH4+ and NO3-.</para> <para>Tree growth was quantified using dendrometer bands on all trees greater than 9cm DBH. Measurements were made monthly during the growing season.</para> <para>Canopy chemistry was evaluated (preferentially sun leaves) at the height of the growing season. Leaves were sampled by shotgun in July or August. Analyses were done for C, N (by CHN analysis), cellulose and lignin (using NIR), 13C and 15N (stable isotope mass spectroscopy).</para> <para>Spring budbreak was measured by visually estimating for each tree the percentage of its leaves that had emerged from their buds.</para> <para>Litterfall was collected each fall from permanent baskets installed in the plots. Wire baskets dispersed throughout the plots were used from 2003-2009; laundry baskets clustered in the center of the plots were used from 2006-present.</para> <para>Water holding capacity was measured as field capacity; the mass of water the soil can retain against gravity drainage. Soil samples were saturated in water for 24 hours in mesh-bottomed tubes, and then placed on a metal grate and allowed to drain for another 24 hours. After draining, the water content of the soil was measured gravimetrically (soil samples were weighed, dried in an oven at 105 C for 48 hours, then reweighed).</para> <para>SOM content was measured by combustion in a muffle furnace at 550 C for 4 hours. Dry soil samples were weighed, combusted, and then reweighed.</para> </section> </description> </methodStep> </methods> <project> <title>Harvard Forest Long-Term Ecological Research 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. hf018-01-trace-gas.csv trace gas (pre-treatment) hf018-01-trace-gas.csv 41076 8d8043a813c9d6af34b21dc5f7852e63 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-01-trace-gas.csv date collection date YYYY-MM-DD NA missing value year year YYYY 1 year NA missing value month month month NA missing value day day day NA missing value treatment treatment treatment NA missing value plot plot number plot number NA missing value ch4 ch4 flux milligramPerMeterSquaredPerHour 0.000000001 real NA missing value n2o n2o flux milligramPerMeterSquaredPerHour 0.000000001 real NA missing value temp2 soil temperature at 2 cm depth celsius 0.01 real NA missing value temp5 soil temperature at 5 cm depth celsius 0.01 real NA missing value 564 hf018-02-canopy-foliage.csv canopy foliage (pre-treatment) hf018-02-canopy-foliage.csv 3727 718997afb6f873723d2d80fc9c63dde8 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-02-canopy-foliage.csv tree tree ID tree ID NA missing value date collection date YYYY-MM-DD NA missing value species species name species name NA missing value plot treatment code c control h heated NA missing value n_per % nitrogen number 0.01 real NA missing value lignin_per % lignin number 0.01 real NA missing value cellulose_per % cellulose number 0.01 real NA missing value 94 hf018-03-soil-temp.csv soil temperature hf018-03-soil-temp.csv 12342977 45cd698480f03f52087743fc02220e35 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-03-soil-temp.csv datetime date and time YYYY-MM-DDThh:mm NA missing value doy Julian day nominalDay 1 whole NA missing value year year YYYY NA missing value time time time NA missing value ctrl_av average soil temperature Control plot celsius 0.01 real NA missing value p1_av average soil temperature Block 1 Heated Plot celsius 0.01 real NA missing value p2_av average soil temperature Block 2 Heated Plot celsius 0.01 real NA missing value p3_av average soil temperature Block 3 Heated Plot celsius 0.01 real NA missing value p4_av average soil temperature Block 4 Heated Plot celsius 0.01 real NA missing value p5_av average soil temperature Block 5 Heated Plot celsius 0.01 real NA missing value p6_av average soil temperature Block 6 Heated Plot celsius 0.01 real NA missing value p7_av average soil temperature Block 7 Heated Plot celsius 0.01 real NA missing value p8_av average soil temperature Block 8 Heated Plot celsius 0.01 real NA missing value p9_av average soil temperature Block 8 Heated Plot celsius 0.01 real NA missing value p10_av average soil temperature Block 10 Heated Plot celsius 0.01 real NA missing value 131002 hf018-04-soil-moisture.csv soil moisture hf018-04-soil-moisture.csv 13698258 bc8c0a0ca8643a6f2a80b8d2f43423ac 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-04-soil-moisture.csv datetime date and time YYYY-MM-DDThh:mm NA missing value year year YYYY NA missing value doy Julian day nominalDay 1 whole NA missing value time time time NA missing value tdr1 soil moisture TDR probe 1 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr2 soil moisture TDR probe 2 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr3 soil moisture TDR probe 3 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr4 soil moisture TDR probe 4 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr5 soil moisture TDR probe 5 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr6 soil moisture TDR probe 6 in the Heated Plot (%VWC) dimensionless 0.01 real NA missing value tdr7 soil moisture TDR probe 1 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value tdr8 soil moisture TDR probe 2 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value tdr9 soil moisture TDR probe 3 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value tdr10 soil moisture TDR probe 4 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value tdr11 soil moisture TDR probe 5 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value tdr12 soil moisture TDR probe 6 in the Control Plot (%VWC) dimensionless 0.01 real NA missing value probeset set of soil moisture probes 0 original set of soil moisture probes installed in 2003 1 set of replacement probes installed in control plot in 2016 (original probes retained in heated plot) NA missing value 134107 hf018-05-lysimeter.csv lysimeter hf018-05-lysimeter.csv 25205 9ce77472250deffa14285e59239ff67c 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-05-lysimeter.csv date collection date YYYY-MM-DD NA missing value year year YYYY NA missing value month month month NA missing value day day day NA missing value plot plot ID plot ID NA missing value treatment treatment C control plot H heated plot NA missing value nh4 ammonium milligramsPerLiter 0.01 real NA missing value no3 nitrate milligramsPerLiter 0.01 real NA missing value 725 hf018-06-nmin.csv nitrogen mineralization hf018-06-nmin.csv 88956 69198f35d8bb237ad3d7fa46a09a541f 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-06-nmin.csv year year YYYY NA missing value month month month NA missing value treatment treatment c control plot h heated plot NA missing value plot plot ID plot ID NA missing value sum_ion NH4 + NO3 (kgN/ha/month) kilogramsPerHectarePerMonth 0.0001 real NA missing value nh4 ammonification rate (kgN/ha/monh) kilogramsPerHectarePerMonth 0.0001 real NA missing value no3 nitrification rate (kgN/ha/month) kilogramsPerHectarePerMonth 0.0001 real NA missing value 3060 hf018-07-soil-respiration.csv soil respiration hf018-07-soil-respiration.csv 474079 2d213d9e0f0d49a2d40082b8ddde46f3 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-07-soil-respiration.csv datetime collection date and time collection date and time NA missing value date collection date YYYY-MM-DD NA missing value year year YYYY NA missing value month month month NA missing value day day day NA missing value time time hh:mm NA missing value treatment treatment code C control plot H heated plot NA missing value plot subplot within the megaplot subplot within the megaplot NA missing value co2 CO2 flux in mg C m-2 h-1 milligramPerMeterSquaredPerHour 0.01 real NA missing value cm2 soil temperature at 2 cm depth celsius 0.01 real NA missing value cm4 soil temperature at 4 cm depth celsius 0.01 real NA missing value moisture soil moisture (% volumetric moisture content) dimensionless 0.001 real NA missing value measurement measurement type Li8100-a automatic LI-COR measurement static static chamber gas syringe measurement NA missing value 5737 hf018-08-dendrology.csv dendrology hf018-08-dendrology.csv 1241536 f1c50346005ce2bd57c0a6f2620f41dd 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-08-dendrology.csv treeid unique identification number assigned to each tree in experiment unique identification number assigned to each tree in experiment NA missing value date date YYYY-MM-DD NA missing value species species code ACPE Acer pensylvanicum, striped maple ACRU Acer rubrum, red maple ACSA Acer saccharum, sugar maple ACSP Acer species, unidentified maple BEAL Betula alleghaniensis, yellow birch BELE Betula lenta, black birch BEPA Betula papyrifera, paper birch BEPO Betula populifolia, gray birch BESP Betula species, unidentified birch CADE Castanea dentata, american chestnut FAGR Fagus grandifolia, american beech FRAM Fraxinus americana, white ash PIST Pinus strobus, white pine POGR Populus grandidentata, bigtooth aspen PRSE Prunus serotina, black cherry QUAL Quercus alba, white oak QURU Quercus rubra, red oak QUSP Quercus species, unidentified oak QUVE Quercus velutina, black oak TSCA Tsuga canadensis, eastern hemlock NA missing value plot plot B wide buffer zone around plots Be portion of buffer zone within 15 meters of an edge Bh portion of buffer zone within 10 meters of heated plot Bhe portion of buffer zone both within 10 meters of heated plot and 15 meters of an edge C control H heated S1 supplemental control plot 1 S2 supplemental control plot 2 S3 supplemental control plot 3 S4 supplemental control plot 4 NA missing value subplot 5x5 meter subplot within the C or H plot 5x5 meter subplot within the C or H plots NA missing value dbh diameter at breast height centimeter 0.01 real NA missing value 33382 hf018-09-litterfall.csv litterfall hf018-09-litterfall.csv 54879 9c144c1d5d7032932784754d737c376a 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-09-litterfall.csv year year YYYY 1 year NA missing value treatment plot C control H heated NA missing value species species code ACPE Acer pensylvanicum, striped maple ACRU Acer rubrum, red maple ACSA Acer saccharum, sugar maple BESP Betula species, unidentified birch CADE Castanea dentata, american chestnut FAGR Fagus grandifolia, american beech FRAM Fraxinus americana, white ash not sorted not sorted OTHER other POGR Populus grandidentata, bigtooth aspen PRSE Prunus serotina, black cherry QUAL Quercus alba, white oak QURU Quercus rubra, red oak UNKN unknown (mostly unidentifiable fragments) NA missing value basket_num unique identification number of litter collection basket unique identification number of litter collection basket NA missing value basket_type type of litter basket WB wire basket (capture area 0.3215 m2) LB laundry basket (capture area 0.2145 m2) NA missing value mass total dry weight of litterfall captured gram 0.01 real NA missing value 2235 hf018-10-foliage-chemistry.csv foliage chemistry hf018-10-foliage-chemistry.csv 46466 9a27e1ddce83da65c2f2ec4e054327b2 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-10-foliage-chemistry.csv year year YYYY 1 year NA missing value treeid unique identification number assigned to each tree in experiment unique identification number assigned to each tree in experiment NA missing value species species code ACRU Acer rubrum, red maple ACSA Acer saccharum, sugar maple BEAL Betula alleghaniensis, yellow birch BEPO Betula populifolia, gray birch BESP Betula species, unidentified birch FRAM Fraxinus americana, white ash QURU Quercus rubra, red oak QUVE Quercus velutina, black oak TSCA Tsuga canadensis, eastern hemlock NA missing value treatment plot H Heated C Control NA missing value n_per weight percent nitrogen dimensionless 0.01 real NA missing value c_per weight percent carbon dimensionless 0.01 real NA missing value c_n molar carbon to nitrogen ratio dimensionless 0.01 real NA missing value d13c d13C, o/oo vs. PDB dimensionless 0.01 real NA missing value d15n d15N, o/oo vs. air dimensionless 0.01 real NA missing value p_per weight percent phosphorus dimensionless 0.00000001 real NA missing value n_p molar nitrogen to phosphorus ratio dimensionless 0.000000001 real NA missing value 816 hf018-11-budbreak.csv spring budbreak hf018-11-budbreak.csv 307944 012da97417a5f1a111d068db12c325b6 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-11-budbreak.csv date collection date YYYY-MM-DD NA missing value tree unique identification number assigned to each tree in experiment unique identification number assigned to each tree in experiment NA missing value plot treatment C Control H Heated NA missing value species species code ACPE Acer pensylvanicum, striped maple ACRU Acer rubrum, red maple ACSA Acer saccharum, sugar maple BEAL Betula alleghaniensis, yellow birch BELE Betula lenta, black birch BEPA Betula papyrifera, paper birch BEPO Betula populifolia, gray birch CADE Castanea dentata, american chestnut FRAM Fraxinus americana, white ash QUAL Quercus alba, white oak QURU Quercus rubra, red oak QUVE Quercus velutina, black oak NA missing value year year YYYY 1 year NA missing value doy day of year (Julian day) nominalDay 1 natural NA missing value budbreak visually estimated percentage of buds from which leaves have emerged and unfolded, to the nearest 10% dimensionless 1 whole NA missing value 8867 hf018-12-litter-chemistry.csv litter chemistry hf018-12-litter-chemistry.csv 57363 e62e578dc004ae51dba96355ca8ada2c 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-12-litter-chemistry.csv year year YYYY 1 year NA missing value species species code ACRU Acer rubrum, red maple ACPE Acer pensylvanicum, striped maple ACSA Acer saccharum, sugar maple ACSP Acer species, unidentified maple BEAL Betula alleghaniensis, yellow birch BELE Betula lenta, black birch BESP Betula species, unidentified birch FRAM Fraxinus americana, white ash CADE Castanea dentata, american chestnut FAGR Fagus grandifolia, american beech POGR Populus grandidentata, bigtooth aspen UNKN unknown (mostly unidentifiable fragments) PIST Pinus strobus, white pine PRSE Prunus serotina, black cherry QUAL Quercus alba, white oak QURU Quercus rubra, red oak QUSP Quercus species, unidentified oak NA missing value treatment plot C control H heated NA missing value basket_num unique identification number of litter collection basket unique identification number of litter collection basket NA missing value basket_type type of litter basket WB wire basket (capture area 0.3215 m2) LB laundry basket (capture area 0.2145 m2) NA missing value c_per weight percent carbon of litter dimensionless 0.001 real NA missing value n_per weight percent nitrogen of litter dimensionless 0.001 real NA missing value c_n molar C:N ratio of litter dimensionless 0.000000001 real NA missing value p_per weight percent phosphorus dimensionless 0.00000001 real NA missing value n_p molar nitrogen to phosphorus ratio dimensionless 0.000000001 real NA missing value 1338 hf018-13-whc.csv water holding capacity hf018-13-whc.csv 5194 257a5d5b083be37cb26543a38dcf8204 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p01/hf018/hf018-13-whc.csv date sampling date YYYY-MM-DD NA missing value plot plot Control control plot Heated heated plot NA missing value subplot 5 x 5 meter subplot within main plots; 1-36 5 x 5 meter subplot within main plots; 1-36 NA missing value horizon horizon Organic organic Mineral mineral NA missing value som soil organic matter content; g organic matter dry weight gram 0.001 real NA missing value whc soil water holding capacity; g water at capacity gram 0.0001 real NA missing value 123 plot soil long-term measurement https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf005 milligramPerMeterSquaredPerHour kilogramsPerHectarePerMonth