European fine root biomass, fine root production and fine root necromass information

Description of columns:<br>author: Reference(s) country: Name of country species: Main tree species, dominant species is first mix: 2 indicate mixed stand proportions: for mixed stands the share of the species is given, in percent of basal area (if basal area is unavailable, stem number, volume or biomass is used) year_mean: year of measurement(s), mean year is given, if data covers several years year_range: range of measurements separated by hyphen, if data covers several years needlebroad: dominant species group 1 conifers, 2 broadleaved species dom_sp: dominant tree species 1 <i>Picea abies</i>, 2 <i>Abies alba</i>, 3 <i>Larix decidua</i>, 4 <i>Pinus sylvestris</i>, 5 <i>Pinus nigra</i>, 8 <i>Pseudotsuga menziessii</i>, 9 other conifers, 10 <i>Fagus sylvatica</i>, 11 <i>Quercus sp.</i>, 12 <i>Carpinus betulus</i>, 13 <i>Fraxinus excelsior</i>, 14 <i>Acer sp</i>., 20 <i>Betula sp</i>., 21 <i>Alnus incana</i>, 22 <i>Alnus glutinosa</i>, 23 <i>Tilia sp</i>., 26 <i>Populus sp.,</i> 31 other broadleaves latitude: latitude in decimal degrees in WGS84 of location of measurements, if not reported approximate location was taken from other references, maps, etc. longitude: longitude in decimal degrees in WGS84 of location of measurements, if not reported approximate location was taken from other references, maps, etc. elevation: elevation in m above sea level, as reported in references temp: average annual temperature, as reported in references precip: annual precipitation sum, as reported in references density: tree density in stem per hectare, if reported basalarea: basal area in square meter per hectare, if reported height: average tree height in meter, if reported diameter: average tree diameter, usually at breast height (1.3 m), if reported volume: stem volume in cubic meter per hectare, if reported age: average stand age in years, if reported leafbiom: reported foliage biomass in kilogram per hectare, if reported soiltype: soil type, as reported in references, if reported soilCN: reported carbon:nitrogen ratio in soil, if reported FRB: fine root biomass with diameter 0-2 mm in gram per square meter understoryFRB: if reported, fine root biomass of understory with diameter 0-2 mm in gram per square meter FRN: fine root necromass with diameter 0-2 mm in gram per square meter necro_bio_separate: 1 if biomass values certainly represent only living roots (clear separation between alive and dead roots mentioned in references) FRBmethod: method used for determining fine root biomass depth: reported sample depth in centimeter FRP: sum of fine root production of trees and understory with diameter 0-2 mm in gram per square meter per year FRPmethod: method used for determining fine root production, 1 sequential coring, 2 ingrowth bags/nets/meshes, 4 minirhizotron SCmethod: description of methodology used to calculate fine root production for sequential coring, if available, dm ... decision matrix or balance transfer, mm ... minimum maximum, cf ... compartment flow, scs ... sum of siginifcant changes, sca ... sum of all significant changes FRP_note: more detailed description of fine root production method fineroot_C: carbon fraction in fine roots in percent fineroot_CN: carbon:nitrogen ratio in fine roots comment: additional comments on data collection, site, methodology, etc.

列字段说明：
author：作者信息
country：国家名称
species：主要树种，优势树种位列首位；mix：取值为2时代表混交林
proportions：针对混交林，给出对应树种的占比（以断面积（basal area）百分比计算；若无断面积数据，则采用株数、蓄积量或生物量占比）
year_mean：调查年份，若调查覆盖多个年度，则给出平均调查年份
year_range：调查年度范围，以连字符分隔，适用于多年度调查数据
needlebroad：优势树种组：1代表针叶树，2代表阔叶树
dom_sp：优势树种编码及对应物种：1 <i>欧洲云杉（*Picea abies*）</i>、2 <i>欧洲冷杉（*Abies alba*）</i>、3 <i>欧洲落叶松（*Larix decidua*）</i>、4 <i>欧洲赤松（*Pinus sylvestris*）</i>、5 <i>黑松（*Pinus nigra*）</i>、8 <i>北美黄杉（*Pseudotsuga menziessii*）</i>、9 其他针叶树；10 <i>欧洲山毛榉（*Fagus sylvatica*）</i>、11 <i>栎属（*Quercus sp.*）</i>、12 <i>欧洲鹅耳枥（*Carpinus betulus*）</i>、13 <i>欧洲白蜡（*Fraxinus excelsior*）</i>、14 <i>槭属（*Acer sp.*）</i>、20 <i>桦木属（*Betula sp.*）</i>、21 <i>灰桤木（*Alnus incana*）</i>、22 <i>欧洲黑桤木（*Alnus glutinosa*）</i>、23 <i>椴属（*Tilia sp.*）</i>、26 <i>杨属（*Populus sp.*）</i>、31 其他阔叶树
latitude：调查点纬度，采用WGS84坐标系的十进制度格式；若未直接报告，则通过其他文献、地图等资料获取近似坐标
longitude：调查点经度，采用WGS84坐标系的十进制度格式；若未直接报告，则通过其他文献、地图等资料获取近似坐标
elevation：海拔高度，单位为米（m），引自文献记载
temp：年平均气温，引自文献记载
precip：年降水总量，引自文献记载
density：林木密度，单位为株/公顷，仅当文献中有相关报告时收录
basalarea：林分断面积，单位为平方米/公顷，仅当文献中有相关报告时收录
height：平均树高，单位为米（m），仅当文献中有相关报告时收录
diameter：平均胸径（通常指1.3米处的树干直径），仅当文献中有相关报告时收录
volume：单位面积林木蓄积量，单位为立方米/公顷，仅当文献中有相关报告时收录
age：林分平均年龄，单位为年，仅当文献中有相关报告时收录
leafbiom：单位面积叶生物量，单位为千克/公顷，仅当文献中有相关报告时收录
soiltype：土壤类型，引自文献记载，仅当文献中有相关报告时收录
soilCN：土壤碳氮比（carbon:nitrogen ratio），仅当文献中有相关报告时收录
FRB：细根生物量（fine root biomass, FRB），直径范围为0-2mm，单位为克/平方米，仅当文献中有相关报告时收录
understoryFRB：林下植被细根生物量，直径范围为0-2mm，单位为克/平方米，仅当文献中有相关报告时收录
FRN：细根坏死生物量，直径范围为0-2mm，单位为克/平方米，仅当文献中有相关报告时收录
necro_bio_separate：若文献中明确区分活根与死根，则该字段取值为1，表示生物量数值仅代表活根生物量
FRBmethod：细根生物量的测定方法
depth：样品采集深度，单位为厘米（cm），引自文献记载
FRP：林木与林下植被的细根总生产量，直径范围为0-2mm，单位为克/平方米·年，仅当文献中有相关报告时收录
FRPmethod：细根生产量的测定方法：1为顺序钻土法，2为植入袋/网/膜法（ingrowth bags/nets/meshes），4为微根管法（minirhizotron）
SCmethod：当采用顺序钻土法计算细根生产量时，若有相关方法说明，则列出所用方法：dm为决策矩阵或余额转移法，mm为最小最大值法，cf为 compartment 流量法（compartment flow），scs为显著变化总和，sca为所有显著变化总和
FRP_note：细根生产量测定方法的详细补充说明
fineroot_C：细根碳组分占比，单位为百分比（%）
fineroot_CN：细根碳氮比（carbon:nitrogen ratio）
comment：关于数据采集、调查样地、测定方法等的补充说明