[
  {
    "table": "trees",
    "field": "INVYR",
    "type": "nullable number",
    "description": "Inventory year",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.4",
      "source_pdf_page": 161,
      "source_intro_excerpt": "Inventory year. See SURVEY.INVYR description for definition.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "STATUSCD",
    "type": "nullable numeric code",
    "description": "FIA tree status code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.15",
      "source_pdf_page": 162,
      "source_intro_excerpt": "Status code. A code indicating whether the sample tree is live, cut, or dead at the time of \nmeasurement. Includes dead and cut trees, which are required to estimate aboveground \nbiomass and net annual volume for growth, mortality, and removals. This code is not used \nwhen querying data for change estimates.\nNote: New and replacement plots use only codes 1 and 2.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "SPCD",
    "type": "nullable numeric code",
    "description": "FIA tree species code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.16",
      "source_pdf_page": 162,
      "source_intro_excerpt": "Species code. An FIA tree species code. Refer to appendix F f or codes.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DIA",
    "type": "nullable number",
    "description": "Tree diameter at the source-defined measurement point",
    "unit": "inches",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.18",
      "source_pdf_page": 163,
      "source_intro_excerpt": "Current diameter. The current diameter, in inches, of the sample tree at the point of \ndiameter measurement. For timber species, diameter is measured at breast height \n(d.b.h.), which is usually measured at 4.5 feet above the ground line on the uphill side of \nthe tree. For woodland species, which are often multi-stemmed, diameter is measured at \nthe ground line or at the stem root collar (d.r.c.), whichever is higher. DIA for woodland \nspecies (DRC) is computed using the following formula:\nDRC = SQRT [SUM (stem diameter\n2)]\nFor additional information about where the tree diameter is measured, see DIAHTCD or \nHTDMP. DIA for live trees contains the measured value. DIA for cut and dead trees \npresents problems associated with uncertainty of when the tree was cut or died as well as \nstr\nuctural deterioration of dead trees. Consult individual FIA work units (table 1-1) for \nex\nplanations of how DIA is collected for dead and cut trees.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "HT",
    "type": "nullable number",
    "description": "Tree total height",
    "unit": "feet",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.20",
      "source_pdf_page": 163,
      "source_intro_excerpt": "Total height. (All live and standing dead tally trees \uf0b31.0 inch d.b.h./d.r.c.) The total length \n(height) of a tree, in feet, from the ground to the tip of the apical meristem beginning in \nPLOT.MANUAL = 1.1. The total length of a tree is not always its actual length. If the main \nstem is broken, the actual length is measured or estimated and the missing piece is added \nto \nthe actual length to estimate total length. The amount added is determined by \nmeasuring the broken piece if it can be located on the ground; otherwise it is estimated. \nThe minimum height for timber species is 5 feet and for woodland species is 1 foot. \nStarting with PLOT.MANUAL = 7.0, the \ncore minimum diameter to qualify for a standing \ndead tree was changed from 5.0 inches to 1.0 inch. Fo r multi-stemmed woodland species, \nthis attribute is based on the length of the longest stem present.\nNote: Prior to PLOT.MANUAL = 7.0, this attribute was tallied as follows:\n\u2022 Core Phase 2: \uf0b35.0-inch d.b.h./d.r.c. live trees. \n\u2022 Core optional Phase 2: 1.0-4.9-inch d.b.h./d.r.c. live trees and \uf0b35.0-inch d.b.h./d.r.c. \nstanding dead trees.\n\u2022 Core Phase 3: \uf0b31.0-inch d.b.h./d.r.c. live trees.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "HTCD",
    "type": "nullable numeric code",
    "description": "FIA height measurement method code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.21",
      "source_pdf_page": 164,
      "source_intro_excerpt": "Height method code. (All live and standing dead tally trees \uf0b31.0 inch d.b.h./d.r.c.) A code \nindicating how length (height) was determined beginning in PLOT.MANUAL = 1.1. Starting \nwit\nh PLOT.MANUAL = 7.0, the core minimum diameter to qualify for a standing dead tree \nwas changed from 5.0 inches to 1.0 inch.\nNote: Prior to PLOT.MANUAL = 7.0, this attribute was tallied as follows:\n\u2022 Core Phase 2: \uf0b35.0-inch d.b.h./d.r.c. live trees. \n\u2022 Core optional Phase 2: 1.0-4.9-inch d.b.h./d.r.c. live trees and \uf0b35.0-inch d.b.h./d.r.c. \nstanding dead trees.\n\u2022 Core Phase 3: \uf0b31.0-inch d.b.h./d.r.c. live trees. \n\u2022 Core optional Phase 3: \uf0b35.0-inch d.b.h./d.r.c. standing dead trees.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "ACTUALHT",
    "type": "nullable number",
    "description": "Actual tree height",
    "unit": "feet",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.22",
      "source_pdf_page": 164,
      "source_intro_excerpt": "Actual height. (All live and standing dead tally trees \uf0b31.0 inch d.b.h./d.r.c.) The length \n(height) of the tree to the nearest foot from ground level to the highest remaining portion \nof the tree still present and attached to the bole. If ACTUALHT = HT, then the tree does \nnot have a broken top. If ACTUALHT <HT, then the tree does have a broken or missing \ntop. The minimum height for timber species is 5 feet and for woodland species is 1 foot. \nStarting with PLOT.MANUAL = 7.0, the \ncore minimum diameter to qualify for a standing \ndead tree was changed from 5.0 inches to 1.0 inch.\nNote: Prior to PLOT.MANUAL = 7.0, this attribute was tallied as follows:\n\u2022 Core Phase 2: live and standing dead trees with broken tops, \uf0b35.0 inches d.b.h./d.r.c. \n\u2022 Core optional Phase 2: live trees 1.0-4.9 inches d.b.h./d.r.c. with broken or missing \ntops.\n\u2022 Core Phase 3: live trees \uf0b31.0 inch d.b.h./d.r.c. (with broken or missing tops) and \nstanding dead trees \uf0b35.0 inches d.b.h./d.r.c. (with broken or missing tops).",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "TREECLCD",
    "type": "nullable numeric code",
    "description": "FIA tree class code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.23",
      "source_pdf_page": 164,
      "source_intro_excerpt": "Tree class code. A code indicating the general quality of the tree. In annual inventory, this \nis the tree class for both live and dead trees at the time of current measurement. In \nperiodic inventory, for cut and dead trees, this is the tree class of the tree at the time it \ndied or was cut. Therefore, cut and dead trees collected in periodic inventory can be \ncoded as growing-stock trees.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "CR",
    "type": "nullable number",
    "description": "Compacted live crown ratio",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.24",
      "source_pdf_page": 165,
      "source_intro_excerpt": "Compacted crown ratio. The percent of the tree bole supporting live, healthy foliage (the \ncrown is ocularly compacted to fill in gaps) when compared to actual length (ACTUALHT). \nWhen PLOT.MANUAL <1.0 the variable may have been a code, which was converted to the \nmidpoint of the ranges represented by the codes, and is stored as a percentage. May not \nbe \npopulated for periodic inventories.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "CCLCD",
    "type": "nullable numeric code",
    "description": "FIA crown class code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.25",
      "source_pdf_page": 165,
      "source_intro_excerpt": "Crown class code. A code indicating the amount of sunlight received and the crown \nposition within the canopy.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "CULL",
    "type": "nullable number",
    "description": "Tree cull proportion reported by FIA",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.28",
      "source_pdf_page": 166,
      "source_intro_excerpt": "Rotten and missing cull. The percent of the cubic-foot volume in a live or dead tally tree \nthat is rotten or missing. This is a calculated value that is derived from the field-recorded \ncull estimate (see CULL_FLD) or a modeled cull estimate.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DECAYCD",
    "type": "nullable numeric code",
    "description": "FIA decay class code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.35",
      "source_pdf_page": 168,
      "source_intro_excerpt": "Decay class code. A code indicating the stage of decay in a standing dead tree \n(STANDING_DEAD_CD = 1). Not populated for standing dead sap lings (1.0-4.9 inches \nd.b.h./d.r.c.) whe n PLOT.MANUAL <7.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "STOCKING",
    "type": "nullable number",
    "description": "Tree stocking contribution",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.36",
      "source_pdf_page": 169,
      "source_intro_excerpt": "Tree stocking. The stocking value, in percent, computed for each live tree. Stocking \nvalues are computed using several specific species equations that were developed from \nnormal yield tables and stocking charts. Resultant values are a function of diameter. The \nstocking of individual trees is used to calculate COND.GSSTK, COND.GSSTKCD, \nCOND.ALSTK, and COND.ALSTKCD on the condition record.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "VOLCFNET",
    "type": "nullable number",
    "description": "Net cubic-foot tree volume",
    "unit": "cubic feet",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.38",
      "source_pdf_page": 169,
      "source_intro_excerpt": "Net cubic-foot stem wood volume. The net cubic-foot volume of wood in the central \nstem of timber species (trees where diameter is measured at breast height [d.b.h.]) \uf0b35.0 \ninc\nhes d.b.h., from a 1-foot stump to a minimum 4-inch top diameter, or to where the \ncentral stem breaks into limbs all of which are <4.0 inches in diameter. Calculated for live \nand standing dead trees. Does not include rotten, missing, and form cull (volume loss due \nto rotten, missing, and form cull defect has been deducted). This is a per tree value and \nmust be multiplied by TPA_UNADJ to obtain per acre information. This attribute is blank \n(null) for timber species with DIA <5.0 inches and for woodland species. Refer to \nappendix K for more information on FIA \n volume, biomass, and carbon estimation.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "VOLCFGRS",
    "type": "nullable number",
    "description": "Gross cubic-foot tree volume",
    "unit": "cubic feet",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.39",
      "source_pdf_page": 170,
      "source_intro_excerpt": "Gross cubic-foot stem wood volume. The total cubic-foot volume of wood in the central \nstem of timber species (trees where diameter is measured at breast height [d.b.h.]) \uf0b35.0 \ninc\nhes d.b.h., from a 1-foot stump to a minimum 4-inch top diameter, or to where the \ncentral stem breaks into limbs all of which are <4.0 inches in diameter. Calculated for live \nand standing dead trees. Includes rotten, missing, and form cull (volume loss due to \nrotten, missing, and form cull defect has not been deducted). This is a per tree value and \nmust be multiplied by TPA_UNADJ to obtain per acre information. This attribute is blank \n(null) for timber species with DIA <5.0 inches and for woodland species. Refer to \nappendix K for information on FIA volume, biomass, and carbon estimation.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "VOLBFNET",
    "type": "nullable number",
    "description": "Net board-foot tree volume",
    "unit": "board feet",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.42",
      "source_pdf_page": 172,
      "source_intro_excerpt": "Net board-foot wood volume in the sawlog portion of a sawtimber tree. The net \nboard-foot (International \u00bc-inch Rule) volume of wood in the central stem of a timber \nspecies tree of sawtimber size (9.0 inches d.b.h. minimum for softwoods, 11.0 inches \nd.b.h. minimum for hardwoods), from a 1-foot stump to a minimum top diameter (7.0 \ninches for softwoods, 9.0 inches for hardwoods), or to where the central stem breaks into \nlimbs all of which are less than the minimum top diameter. This is a per tree value and \nmust be multiplied by TPA_UNADJ to obtain per unit area information. This attribute is \nblank (null) for softwood trees with DIA <9.0 inches (<11.0 inches for hardwoods). All \nsawtimber-size trees have entries in this field if they are growing-stock trees (TREECLCD \n= 2 and STATUSCD = 1). All rough and rotten trees (TREECLCD = 3 or 4) and dead and \ncut trees (STATUSCD = 2 or 3) are blank (null) in this field. Form cull and rotten/missing \ncull are excluded.\nFigure 3-3:  Illustration of timber species net board-foot wood volume in the sawlog porition \nof a sawtimber tree (VOLBFNET) in black. Gray trees and gray parts are excluded. See \nVOLBFNET for a full description of this at",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "TPA_UNADJ",
    "type": "nullable number",
    "description": "Unadjusted trees-per-acre expansion factor",
    "unit": "trees per acre",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.92",
      "source_pdf_page": 185,
      "source_intro_excerpt": "Trees per acre unadjusted. The number of trees per acre that the sample tree \ntheoretically represents based on the sample design. For fixed-radius plots taken with the \nmapped plot design (PLOT.DESIGNCD = 1), TPA_UNADJ is set to a constant derived from \nthe plot size and equals 6.018046 for trees sampled on subplots, 74.965282 for trees \nsam\npled on microplots, and 0.999188 for trees sampled on macroplots. Variable-radius \nplots were often used in earlier inventories, so the value in TPA_UNADJ decreases as the \ntree diameter increases. Based on the procedures described in Bechtold and Patterson \n(2005), this attribute must be adjusted using factors stored in the POP_STRATUM table to \nderive population estimates. Examples of estimating population totals are shown in The \nForest Inventory and Analysis Database: Population Estimation User Guide.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DRYBIO_AG",
    "type": "nullable number",
    "description": "Aboveground dry biomass",
    "unit": "pounds",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.133",
      "source_pdf_page": 200,
      "source_intro_excerpt": "Aboveground dry biomass of wood and bark. The oven-dry biomass, in pounds, of wood \nand bark in the aboveground portion, excluding foliage, of live and standing dead trees \n\uf0b31.0 inch d.b.h./d.r.c. This is a per tree value and must be multiplied by TPA_UNADJ to \nobt\nain per acre information. Refer to appendix K on  FIA volume, biomass, and carbon \nestimation.\nNote: Not populated for standing dead saplings (1.0-4.9 inches d.b.h./d.r.c.) when \nPLO\nT.MANUAL <7.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DRYBIO_BG",
    "type": "nullable number",
    "description": "Belowground dry biomass",
    "unit": "pounds",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.95",
      "source_pdf_page": 186,
      "source_intro_excerpt": "Belowground dry biomass. The oven-dry biomass, in pounds, of the belowground portion \nof a tree, including coarse roots with a root diameter \uf0b30.1 inch. This is a modeled \nest\nimate, calculated for live and standing dead trees \uf0b31.0 inch d.b.h./d.r.c. This is a per \ntre\ne value and must be multiplied by TPA_UNADJ to obtain per acre information. Refer to \nappendix K fo r information on FIA volume, biomass, and carbon estimation.\nNote: Not populated for standing dead saplings (1.0-4.9 inches d.b.h./d.r.c.) when \nPLO\nT.MANUAL <7.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "CARBON_AG",
    "type": "nullable number",
    "description": "Aboveground tree carbon",
    "unit": "pounds",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.96",
      "source_pdf_page": 186,
      "source_intro_excerpt": "Aboveground carbon of wood and bark. The carbon, in pounds, of wood and bark in the \naboveground portion, excluding foliage, of live and standing dead trees \uf0b31.0 inch",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "CARBON_BG",
    "type": "nullable number",
    "description": "Belowground tree carbon",
    "unit": "pounds",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.97",
      "source_pdf_page": 187,
      "source_intro_excerpt": "Belowground carbon. The carbon, in pounds, of the belowground portion of a tree, \nincluding coarse roots with a root diameter \uf0b30.1 inch.  Calculated for live and standing \nde\nad trees \uf0b31.0 inch d.b.h./d.r.c. This is a per tree value and must be multiplied by \nTP\nA_UNADJ to obtain per acre information. The amount of carbon is calculated based on \napplying species-specific carbon fractions to the belowground biomass:\nCARBON_BG = REF _SPECIES.CARBON_RATIO_LIVE * DRYBIO_BG\nRefer to appendix K for information on FIA volume, biomass, and carbon estimation.\nNote: Not populated for standing dead saplings (1.0-4.9 inches d.b.h./d.r.c.) when \nPLO\nT.MANUAL <7.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "STANDING_DEAD_CD",
    "type": "nullable numeric code",
    "description": "FIA standing-dead status code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.89",
      "source_pdf_page": 184,
      "source_intro_excerpt": "Standing dead code. A code indicating if a tree qualifies as standing dead. To qualify as a \nstanding dead tally tree, the dead tree must be \uf0b31.0 inch d.b.h., have a bole that has an \nunb\nroken actual length (ACTUALHT) \uf0b34.5 feet, and lean <45 d egrees from vertical as \nmeasured from the base of the tree to 4.5 feet. For woodland species with multiple stems, \n31 Short-log Cull - Any live sawtimber-size tree of commercial species that has at least \none 8-foot sawlog, but < a 12-foot sawlog, meeting minimum log-grade \nspecifications. Any live sawtimber-size tree of commercial species that has less than \none-third of the volume of the sawlog portion in merchantable logs, but has at least \none 8-foot or longer sawlog meeting minimum log-grade specifications. A short \nsawlog must be 50 percent sound at any point. Pole-size trees never receive a tree \nclass code 31.\n40 Rotten Cull - Any live tree of commercial species that is sawtimber size and has no \nmerchantable sawlog. Over one-half of the volume in the sawlog portion does not \nmeet minimum log-grade specifications primarily because of rot, missing sections, or \ndeadwood. Classify any pole-size tree that does not have the potential to",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DAMAGE_AGENT_CD1",
    "type": "nullable numeric code",
    "description": "FIA damage agent code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.120",
      "source_pdf_page": 191,
      "source_intro_excerpt": "Damage agent code 1. (core: all live tally trees \uf0b35.0 inches d.b.h./d.r.c; core optional: all \nlive tally trees \uf0b31.0 inch d.b.h./d.r.c.) A code indicating the first damage agent recorded by \nthe field crew when inspecting the tree from bottom to top (roots, bole, branches, \nfoliage). Up to three damage agents can be recorded per tree (DAMAGE_AGENT_CD1, \nDAMAGE_AGENT_CD2, and DAMAGE_AGENT_CD3). Damage agents are not necessarily \nrecorded in order of severity.The codes used for damage agents come from the January \n2012 Pest Trend Impact Plot System (PTIPS) list from the Forest Health Assessment and \nApplied Sciences Team (FHAAST) that has been modified to meet FIA's needs. The list is \nmodified by each region to meet the specific needs of that region. The general agent \ncodes are listed here. See appendix H for the complete list of codes.\nNote: Starting with PLOT.MANUAL = 9.4, damage agent code = 90001 (broken top) was \nretired and replaced with TREE.ABNORMAL_TERMINATION.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DAMAGE_AGENT_CD2",
    "type": "nullable numeric code",
    "description": "FIA damage agent code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.121",
      "source_pdf_page": 198,
      "source_intro_excerpt": "Damage agent code 2. (core: all live tally trees \uf0b35.0 inches d.b.h./d.r.c; core optional: all \nlive tally trees \uf0b31.0 inch d.b.h./d.r.c.) See DAMAGE_AGENT_CD1.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "DAMAGE_AGENT_CD3",
    "type": "nullable numeric code",
    "description": "FIA damage agent code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "3.1.122",
      "source_pdf_page": 198,
      "source_intro_excerpt": "Damage agent code 3. (core: all live tally trees \uf0b35.0 inches d.b.h./d.r.c; core optional: all \nlive tally trees \uf0b31.0 inch d.b.h./d.r.c.) See DAMAGE_AGENT_CD1.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "trees",
    "field": "record_count",
    "type": "positive integer",
    "description": "Number of retained source observations with this identical normalized feature vector. This is multiplicity, not a survey expansion weight.",
    "unit": "source observations",
    "missing": "never missing"
  },
  {
    "table": "conditions",
    "field": "INVYR",
    "type": "nullable number",
    "description": "Inventory year",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.3",
      "source_pdf_page": 70,
      "source_intro_excerpt": "Inventory year. See SURVEY.INVYR description for definition.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "COND_STATUS_CD",
    "type": "nullable numeric code",
    "description": "FIA condition status code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.9",
      "source_pdf_page": 71,
      "source_intro_excerpt": "Condition status code. A code indicating the basic land classification. \nNote: Starting with PLOT.MANUAL \uf0b36.0, codes 1 and 2 have been modified to match FIA's \nnew definition for accessible forest land and nonforest land. The current wording of \"at \nleast 10 percent canopy cover\" replaces older wording of \"at least 10 percent stocked\" as \nthe qualifying criterion in classification. This criterion applies to any tally tree species, \nincluding woodland tree species.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "FORTYPCD",
    "type": "nullable numeric code",
    "description": "Calculated forest type code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.15",
      "source_pdf_page": 75,
      "source_intro_excerpt": "Forest type code. This is the forest type used for reporting purposes. It is primarily \nderived using a computer algorithm, except when less than 25 percent of the plot samples \na particular forest condition or in a few cases where the derived FORTYPCDCALC does not \naccurately reflect the actual condition.\nNonstocked forest land is land that currently has less than 10 percent stocking but \nform\nerly met the definition of forest land. Forest conditions meeting this definition have \nfew, if any, trees sampled. In these instances, the algorithm cannot assign a specific forest \ntype and the resulting forest type code is 999, meaning nonstocked. See ALSTKCD for \ninformation on estimates of nonstocked areas.\nRefer to appendix D fo\n r the complete list of forest type codes and names.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "FLDTYPCD",
    "type": "nullable numeric code",
    "description": "Field forest type code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.16",
      "source_pdf_page": 75,
      "source_intro_excerpt": "Field forest type code. A code indicating the forest type, assigned by the field crew, \nbased on the tree species or species groups forming a plurality of all live stocking. The \nfield crew assesses the forest type based on the acre of forest land around the plot, in \naddition to the species sampled on the condition. Refer to appendix D fo r a detailed list of \nforest type codes and names. Nonstocked forest land is land that currently has less than \n10 p\nercent stocking but formerly met the definition of forest land. When PLOT.MANUAL \n<2.0, forest conditions that do not meet this stocking level were coded FLDTYPCD = 999. \nStarting with PLOT.MANUAL = 2.0, the crew no longer recorded nonstocked as 999. \nInstead, they recorded FLDSZCD = 0 to identify nonstocked conditions and entered an \nestimated forest type for the condition. The crew determined the estimated forest type by \neither recording the previous forest type on remeasured plots or, on all other plots, the \nmost appropriate forest type to the condition based on the seedlings present or the forest \ntype of the adjacent forest stands. Periodic inventories will differ in the way FLDTYPCD \nwas recorded - it is best to check with ",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "STDAGE",
    "type": "nullable number",
    "description": "Stand age",
    "unit": "years",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.18",
      "source_pdf_page": 76,
      "source_intro_excerpt": "Stand age. For annual inventories (PLOT.MANUAL \uf0b31.0), stand age is equal to the \nfie\nld-recorded stand age (FLDAGE) with some exceptions:\n\u2022 When FLDAGE = 999, tree cores are first sent to the office for the counting of rings. \nStand age is then estimated based upon the average total age of live trees that fall \nwithin the calculated stand-size assignment.\n\u2022 When FLDAGE = 998, STDAGE may be blank (null) because no trees were cored in the \nfield.\n\u2022 If no tree ages are available, then RMRS (SURVEY.RSCD = 22) sets this attribute equal \nto FLDAGE.\nFor annual inventories, nonstocked stands have STDAGE set to 0. When FLDSZCD = 0 \n(no\nnstocked) but STDSZCD <5 (not nonstocked), STDAGE may be set to 0 because \nFLDAGE = 0. Annual inventory data will contain stand ages assigned to the nearest year. \nFor periodic data, stand age was calculated using various methods. Contact the \nappropriate FIA work unit (table 1-1) for details.\n2\n.5.19 STDSZCD\nStand-size class code. A classification of the predominant (based on stocking) diameter \nclass of live trees within the condition assigned using an algorithm. Large diameter trees \nare at least 11.0 inches diameter for hardwoods and at least 9.0 inches d",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "STDSZCD",
    "type": "nullable numeric code",
    "description": "Stand size class code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.19",
      "source_pdf_page": 76,
      "source_intro_excerpt": "Stand-size class code. A classification of the predominant (based on stocking) diameter \nclass of live trees within the condition assigned using an algorithm. Large diameter trees \nare at least 11.0 inches diameter for hardwoods and at least 9.0 inches diameter for \nsoftwoods. Medium diameter trees are at least 5.0 inches diameter and smaller than large \ndiameter trees. Small diameter trees are <5.0 inches diameter. When <25 percent of the \nplot samples the forested condition (CONDPROP_UNADJ <0.25), this attribute is set to the \nequivalent field-recorded stand-size class (FLDSZCD). Populated for forest conditions. This \nattribute is blank (null) for periodic plots that are used only for growth, mortality and \nremoval estimates, and modeling of reserved and unproductive conditions.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "SITECLCD",
    "type": "nullable numeric code",
    "description": "Site productivity class",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.21",
      "source_pdf_page": 77,
      "source_intro_excerpt": "Site productivity class code. A code indicating the classification of forest land in terms of \ninherent capacity to grow crops of industrial wood. Identifies the potential growth in cubic \nfeet/acre/year and is based on the culmination of mean annual increment of fully stocked \nnatural stands. This attribute may be assigned based on the site trees available for the \nplot, or, if no valid site trees are available, this attribute is set equal to SITECLCDEST, a \ndefault value that is either an estimated or predicted site productivity class. If \nSITECLCDEST is used to populate SITECLCD, the attribute SITECL_METHOD is set to 6.\n3 Small diameter - Stands with an all live stocking value of at least 10 (base 100) on \nwhich at least 50 percent of the stocking is in small diameter trees.\n5 Nonstocked - Forest land with all live stocking value <10.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "SICOND",
    "type": "nullable number",
    "description": "Condition site index",
    "unit": "feet at base age",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.22",
      "source_pdf_page": 78,
      "source_intro_excerpt": "Site index for the condition. This represents the average total length in feet that \ndominant and co-dominant trees are expected to attain in well-stocked, even-aged stands \nat the specified base age (SIBASE). Site index is estimated for the condition by either \nusing an individual tree or by averaging site index values that have been calculated for \nindividual site trees (see SITETREE.SITREE) of the same species (SISP). As a result, it \nmay be possible to find additional site index values that are not used in the calculation of \nSIC\nOND in the SITETREE tables when site index has been calculated for more than one \nspecies in a condition. Site index values in SICOND are often used to calculate productivity \nclass and other condition-level attributes. This attribute is blank (null) when no site index \ndata are available.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "SIBASE",
    "type": "nullable number",
    "description": "Site-index base age",
    "unit": "years",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.23",
      "source_pdf_page": 78,
      "source_intro_excerpt": "Site index base age. The base age (sometimes called reference age), in years, of the site \nindex curve used to derive site index. Base age may be breast height age or total age, \ndepending on the specifications of the site index curves being used. This attribute is blank \n(null) when no site tree data are available.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "SISP",
    "type": "nullable numeric code",
    "description": "Site-index species code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.24",
      "source_pdf_page": 78,
      "source_intro_excerpt": "Site index species code. The species upon which the site index is based. In most cases, \nthe site index species will be one of the species that define the forest type of the condition \n(FORTYPCD). In cases where there are no suitable site trees of the type species, other \nsuitable species may be used. This attribute is blank (null) when no site tree data are \navailable.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "STDORGCD",
    "type": "nullable numeric code",
    "description": "Stand origin code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.25",
      "source_pdf_page": 78,
      "source_intro_excerpt": "Stand origin code. A code indicating the method of stand regeneration for the trees in the \ncondition. An artificially regenerated stand is established by planting or artificial seeding. \nPopulated for forest conditions.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "PHYSCLCD",
    "type": "nullable numeric code",
    "description": "Physiographic class code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.34",
      "source_pdf_page": 80,
      "source_intro_excerpt": "Physiographic class code. A code indicating the general effect of land form, topographical \nposition, and soil on moisture available to trees. \nNote: When PLOT.MA NUAL <1.0, this attribute is populated for all forest periodic plots \nand all NCRS periodic plots that were measured as \"nonforest with trees\" (e.g., wooded \npasture, windbreaks).",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBCD1",
    "type": "nullable numeric code",
    "description": "FIA disturbance code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.37",
      "source_pdf_page": 83,
      "source_intro_excerpt": "Disturbance code 1. A code indicating the kind of disturbance occurring since the last \nmeasurement or within the last 5 years for new plots. The area affected by the \ndisturbance must be at least 1 acre in size. A significant level of disturbance (mortality or \ndamage to 25 percent of the trees in the condition) is required. Up to three different \ndisturbances per condition can be recorded, from most important to least important \n(DSTRBCD1, DSTRBCD2, and DSTRBCD1). May not be populated for some FIA work units \nwhen PLOT.MANUAL <1.0. Codes 11, 12, 21, and 22 are valid where PLOT.MANUAL \uf0b32.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBYR1",
    "type": "nullable number",
    "description": "Year of recorded disturbance",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.38",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Disturbance year 1. The year in which disturbance 1 (DSTRBCD1) is estimated to have \noccurred. If the disturbance occurs continuously over a period of time, the value 9999 is \nused. If DSTRBCD1 = 0, then DSTRBYR1 = blank (null) or 0. May not be populated for \nsome FIA work units when PLOT.MANUAL<1.0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBCD2",
    "type": "nullable numeric code",
    "description": "FIA disturbance code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.39",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Disturbance code 2. The second disturbance code, if the stand has experienced more \nthan one disturbance. See DSTRBCD1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBYR2",
    "type": "nullable number",
    "description": "Year of recorded disturbance",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.40",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Disturbance year 2. The year in which disturbance 2 (DSTRBCD2) occurred. See \nDSTRBYR1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBCD3",
    "type": "nullable numeric code",
    "description": "FIA disturbance code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.41",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Disturbance code 3. The third disturbance code, if the stand has experienced more than \ntwo disturbances. See DSTRBCD1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "DSTRBYR3",
    "type": "nullable number",
    "description": "Year of recorded disturbance",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.42",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Disturbance year 3. The year in which disturbance 3 (DSTRBCD3) occurred. See \nDSTRBYR1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTCD1",
    "type": "nullable numeric code",
    "description": "FIA treatment code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.43",
      "source_pdf_page": 84,
      "source_intro_excerpt": "Treatment code 1. A code indicating the type of stand treatment that has occurred since \nthe last measurement or within the last 5 years for new plots. The area affected by the \ntreatment must be at least 1 acre in size. Populated for all forested conditions using the \nNational Field Guide protocols (PLOT.MANUAL \uf0b31.0) and populated by some FIA work \nunit\ns where PLOT.MANUAL <1.0. When PLOT.MANUAL <1.0, inventories may record \ntreatments occurring within the last 20 years for new plots. Up to three different \ntreatments per condition can be recorded, from most important to least important \n(TRTCD1, TRTCD2, and TRTCD3).\n54 Drought.\n60 Vegetation (suppression, competition, vines).\n70 Unknown / not sure / other.\n80 Human-induced damage - any significant threshold of human-caused damage \nnot described in the DISTURBANCE codes or in the TREATMENT codes.\n90 Geologic disturbances.\n91 Landslide.\n92 Avalanche track.\n93 Volcanic blast zone.\n94 Other geologic event.\n95 Earth movement / avalanches.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTYR1",
    "type": "nullable number",
    "description": "Year of recorded treatment",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.44",
      "source_pdf_page": 85,
      "source_intro_excerpt": "Treatment year 1. The year in which treatment 1 (TRTCD1) is estimated to have \noccurred. Populated for all forested conditions that have some treatment using the \nNational Field Guide protocols (PLOT.MANUAL \uf0b31.0) and populated by some FIA work \nuni\nts where PLOT.MANUAL <1.0. If TRTCD1 = 00 then TRTYR1 = blank (null) or 0.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTCD2",
    "type": "nullable numeric code",
    "description": "FIA treatment code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.45",
      "source_pdf_page": 85,
      "source_intro_excerpt": "Treatment code 2. The second treatment code, if the stand has experienced more than \none treatment since the last measurement or within the last 5 years for new plots. See \nTRTCD1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTYR2",
    "type": "nullable number",
    "description": "Year of recorded treatment",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.46",
      "source_pdf_page": 85,
      "source_intro_excerpt": "Treatment year 2. The year in which treatment 2 (TRTCD2) is estimated to have \noccurred. See TRTYR1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTCD3",
    "type": "nullable numeric code",
    "description": "FIA treatment code",
    "unit": "code",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.47",
      "source_pdf_page": 85,
      "source_intro_excerpt": "Treatment code 3. The third treatment code, if the stand has experienced more than two \ntreatments since the last measurement or within the last 5 years for new plots. See \nTRTCD1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "TRTYR3",
    "type": "nullable number",
    "description": "Year of recorded treatment",
    "unit": "year",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.48",
      "source_pdf_page": 85,
      "source_intro_excerpt": "Treatment year 3. The year in which treatment 3 (TRTCD3) is estimated to have \noccurred. See TRTYR1 for more information.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "BALIVE",
    "type": "nullable number",
    "description": "Live-tree basal area",
    "unit": "square feet per acre",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.50",
      "source_pdf_page": 86,
      "source_intro_excerpt": "Basal area per acre of live trees. Basal area in square feet per acre of all live trees \uf0b31.0 \ninc\nh d.b.h./d.r.c. sampled in the condition. Populated for forest conditions.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "ALSTK",
    "type": "nullable number",
    "description": "All live-tree stocking",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.52",
      "source_pdf_page": 87,
      "source_intro_excerpt": "All-live-tree stocking percent. The sum of stocking percent values of all live trees, \nincluding seedlings, on the condition. The percent is then assigned to a stocking class, \nwhich is found in ALSTKCD. Populated for forest conditions. May not be populated for \nso\nme FIA work units when PLOT.MANUAL <1.0.\nNote: Some periodic survey data are in the form of an absolute stocking value (0-167). \nMor\ne detailed information on how stocking values were determined from plot data in a \nparticular State can be obtained directly from the FIA work units (table 1-1).\n2.\n5.53 GSSTK\nGrowing-stock stocking percent. The sum of stocking percent values of all growing-stock \ntrees and seedlings on the condition. The percent is then assigned to a stocking class, \nwhich is found in GSSTKCD. Growing-stock trees are those where tree class \n(T\nREE.TREECLCD) equals 2. The following species groups (TREE.SPGRPCD) are not \nincluded: 23 (woodland softwoods), 43 (eastern noncommercial hardwoods), and 48 \n(woo\ndland hardwoods). Populated for forest conditions. May not be populated for some \nFIA work units when PLOT.MANUAL <1.0.\nNote: Some periodic survey data are in the form of an absolute stocking value (0-167).",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "GSSTK",
    "type": "nullable number",
    "description": "Growing-stock stocking",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.53",
      "source_pdf_page": 87,
      "source_intro_excerpt": "Growing-stock stocking percent. The sum of stocking percent values of all growing-stock \ntrees and seedlings on the condition. The percent is then assigned to a stocking class, \nwhich is found in GSSTKCD. Growing-stock trees are those where tree class \n(T\nREE.TREECLCD) equals 2. The following species groups (TREE.SPGRPCD) are not \nincluded: 23 (woodland softwoods), 43 (eastern noncommercial hardwoods), and 48 \n(woo\ndland hardwoods). Populated for forest conditions. May not be populated for some \nFIA work units when PLOT.MANUAL <1.0.\nNote: Some periodic survey data are in the form of an absolute stocking value (0-167). \nMor\ne detailed information on how stocking values were determined from plot data in a \nparticular State can be obtained directly from the FIA work units (table 1-1).\n2.\n5.54 FORTYPCDCALC\nForest type code calculated. Forest type is calculated based on the tree species sampled \non the condition. The forest typing algorithm is a hierarchical procedure applied to the \ntree species sampled on the condition. The algorithm begins by comparing the live tree \nstocking of softwoods and hardwoods and continues in a stepwise fashion comparing \nsuccessively smaller subgroups of t",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "CARBON_DOWN_DEAD",
    "type": "nullable number",
    "description": "Carbon down dead",
    "unit": "tons per acre; consult FIADB guide",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.66",
      "source_pdf_page": 91,
      "source_intro_excerpt": "Carbon in down dead. Carbon, in tons per acre, of woody material >3 inches in diameter \non the ground, and stumps and their roots >3 inches in diameter. Estimated from models \nbased on geographic area, forest type, and live tree carbon density (Smith and Heath \n2008). This modeled attribute is not a direct sum of Phase 2 or Phase 3 measurements. \nThis is a per acre estimate and must be multiplied by CONDPROP_UNADJ and the \nappropriate expansion and adjustment factor located in the POP_STRATUM table.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "CARBON_LITTER",
    "type": "nullable number",
    "description": "Carbon litter",
    "unit": "tons per acre; consult FIADB guide",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.67",
      "source_pdf_page": 91,
      "source_intro_excerpt": "Carbon in litter. Carbon, in tons per acre, of organic material on the floor of the forest, \nincluding fine woody debris, humus, and fine roots in the organic forest floor layer above \nmineral soil. Estimated from a model based on on litter carbon measurements from a \nsubset of FIA plots, geographic area, elevation, forest type group, aboveground live tree \ncarbon, and climate variables (Domke and others 2016). This modeled attribute, while \nbased on litter carbon observations on FIA plots, is not a direct sum of Phase 2 or Phase 3 \nmeasurements. This is a per acre estimate and must be multiplied by CONDPROP_UNADJ \nand the appropriate expansion and adjustment factor located in the POP_STRATUM table. \nNot populated for the Caribbean Islands, Pacific Islands, and Interior Alaska.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "CARBON_SOIL_ORG",
    "type": "nullable number",
    "description": "Carbon soil org",
    "unit": "tons per acre; consult FIADB guide",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.68",
      "source_pdf_page": 91,
      "source_intro_excerpt": "Carbon in soil organic material. Carbon, in tons per acre, in fine organic material below \nthe soil surface to a depth of 1 meter. Does not include roots. Estimated from a model \nbased on soil organic carbon measurements from a subset of FIA plots, geographic area, \nelevation, forest type group, climate variables, soil order, and surficial geology (Domke \nand others 2017). This modeled attribute, while based on soil organic carbon observations \non FIA plots, is not a direct sum of Phase 2 or Phase 3 measurements. This is a per acre \nestimate and must be multiplied by CONDPROP_UNADJ and the appropriate expansion \nand adjustment factor located in the POP_STRATUM table. Not populated for the \nCaribbean Islands, Pacific Islands, and Interior Alaska.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "CARBON_UNDERSTORY_AG",
    "type": "nullable number",
    "description": "Carbon understory ag",
    "unit": "tons per acre; consult FIADB guide",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.69",
      "source_pdf_page": 91,
      "source_intro_excerpt": "Carbon in understory aboveground. Carbon, in tons per acre, in the aboveground \nportions of seedlings and woody shrubs. Estimated from models based on geographic \narea, forest type, and (except for nonstocked and pinyon-juniper stands) live tree carbon \ndensity (Smith and Health 2008). This modeled attribute is a component of the EPA's \nGreenhouse Gas Inventory and is not a direct sum of Phase 2 or Phase 3 measurements. \nThis is a per acre estimate and must be multiplied by CONDPROP_UNADJ and the \nappropriate expansion and adjustment factor located in the POP_STRATUM table.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "CARBON_UNDERSTORY_BG",
    "type": "nullable number",
    "description": "Carbon understory bg",
    "unit": "tons per acre; consult FIADB guide",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.70",
      "source_pdf_page": 91,
      "source_intro_excerpt": "Carbon in understory belowground. Carbon, in tons per acre, in the belowground \nportions of seedlings and woody shrubs. Estimated from models based on geographic \narea, forest type, and (except for nonstocked and pinyon-juniper stands) live tree carbon \ndensity (Smith and Heath 2008). This modeled attribute is a component of the EPA's \nGreenhouse Gas Inventory and is not a direct sum of Phase 2 or Phase 3 measurements. \n5 Site index or site productivity class estimated using multiple site trees.\n6 Site index or site productivity class estimated using default values.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "LIVE_CANOPY_CVR_PCT",
    "type": "nullable number",
    "description": "Live canopy cover",
    "unit": "percent",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.96",
      "source_pdf_page": 101,
      "source_intro_excerpt": "Live canopy cover percent. The percentage of live canopy cover for the condition. \nIncluded are live tally trees, saplings, and seedlings that cover the sample area.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "NBR_LIVE_STEMS",
    "type": "nullable number",
    "description": "Estimated live stems per acre on the condition",
    "unit": "stems per acre",
    "missing": "empty CSV cell; source missing values preserved; no imputation",
    "source_definition": {
      "source_section": "2.5.98",
      "source_pdf_page": 101,
      "source_intro_excerpt": "Number of live stems. The estimated number of live stems per acre on the condition. The \nestimate in the field is based on actual stem count of tally tree species within the canopy \ncover for sample area.",
      "note": "Brief text-extracted introduction. Consult original guide section for complete definitions, code tables and footnotes."
    }
  },
  {
    "table": "conditions",
    "field": "record_count",
    "type": "positive integer",
    "description": "Number of retained source observations with this identical normalized feature vector. This is multiplicity, not a survey expansion weight.",
    "unit": "source observations",
    "missing": "never missing"
  }
]