Tree density and the 48 explanatory variables of the 4367 plots in North American boreal forests.

<p dir="ltr">Location: North American boreal forests</p><p dir="ltr">Size: 4367 plots</p><p dir="ltr">Type: ABMI, NFI, PSP plots</p><p dir="ltr">Prov: province, territory or state where the plot is</p><p dir="ltr">Obs_Density: tree density from field measurement (trees/ha; DBH >= 10.0 cm).</p><p dir="ltr">Est_Crowther_Density: tree density estimates from Crowther et al.'s biome map (trees/ha).</p><p dir="ltr">HumanDev: percent of developed and managed land</p><p dir="ltr">HumanPop: population density (km^-2)</p><p dir="ltr">Landcover: land cover type defined in the Land Cover Classification System (LCCS)</p><p dir="ltr">Long: longitude (° W)</p><p dir="ltr">Lat: latitude (° N)</p><p dir="ltr">Elev: elevation (m)</p><p dir="ltr">Slope: angle of inclination of the terrain (°)</p><p dir="ltr">Eastness: sine of aspect of the terrain to north</p><p dir="ltr">Northness: cosine of aspect of the terrain to north</p><p dir="ltr">TRI: terrain ruggedness index</p><p dir="ltr">Standht: stand height as mean height of the tallest 3 trees (m)</p><p dir="ltr">Standht2: square of Standht (m²)</p><p dir="ltr">Canopyht: canopy height from Sentinel-2 imagery (m)</p><p dir="ltr">LAI: leaf area index</p><p dir="ltr">EVI: enhanced vegetation index</p><p dir="ltr">NDVI: normalized difference vegetation index</p><p dir="ltr">ASM_EVI: angular second moment (orderliness) of EVI</p><p dir="ltr">Homogeneity_EVI: similarity of EVI between adjacent pixels</p><p dir="ltr">Contrast_EVI: exponentially weighted difference in EVI between adjacent pixels</p><p dir="ltr">Dissimilarity_EVI: difference in EVI between adjacent pixels</p><p dir="ltr">TCECC: cation exchange capacity of the clay fraction in the topsoil (soil between 0 and 30 cm under the ground) (cmol kg^-1)</p><p dir="ltr">TpHH2O: topsoil pH (in water)</p><p dir="ltr">TC: topsoil carbon content (kg C m^-2)</p><p dir="ltr">AET: actual evapotranspiration as water use (mm day^-1)</p><p dir="ltr">Alpha: Priestley-Taylor alpha coefficient for soil water deficit</p><p dir="ltr">nhx: anthropogenic NHx input (g N m^-2 year^-1)</p><p dir="ltr">noy: anthropogenic NOy input (g N m^-2 year^-1)</p><p dir="ltr">Evapotranspiration: Penman-Monteith reference evapotranspiration (mm day^-1)</p><p dir="ltr">Aridity: ration between mean annual precipitation and mean annual Penman-Monteith reference evapotranspiration</p><p dir="ltr">Solar_Radiation: incident solar radiation (kJ m^-2 day^-1)</p><p dir="ltr">Wind: wind speed at 2 m above the ground (m s^-1)</p><table><tr><td><p dir="ltr">BIO1: Mean annual temperature (℃)</p></td></tr><tr><td><p dir="ltr">BIO2: Mean diurnal range (mean of monthly difference between maximum and minimum temperature) (℃)</p></td></tr><tr><td><p dir="ltr">BIO3: Isothermality (BIO2/BIO7 * 100)</p></td></tr><tr><td><p dir="ltr">BIO4: Temperature seasonality (standard deviation of monthly temperature) (℃)</p></td></tr><tr><td><p dir="ltr">BIO5: Maximum temperature of warmest month (℃)</p></td></tr><tr><td><p dir="ltr">BIO6: Minimum temperature of coldest month (℃)</p></td></tr><tr><td><p dir="ltr">BIO7: Temperature annual range (BIO5-BIO6) (℃)</p></td></tr><tr><td><p dir="ltr">BIO8: Mean temperature of wettest quarter (℃)</p></td></tr><tr><td><p dir="ltr">BIO9: Mean temperature of driest quarter (℃)</p></td></tr><tr><td><p dir="ltr">BIO10: Mean temperature of warmest quarter (℃)</p></td></tr><tr><td><p dir="ltr">BIO11: Mean temperature of coldest quarter (℃)</p></td></tr><tr><td><p dir="ltr">BIO12: Annual precipitation (mm)</p></td></tr><tr><td><p dir="ltr">BIO13: Precipitation of wettest month (mm)</p></td></tr><tr><td><p dir="ltr">BIO14: Precipitation: driest month (mm)</p></td></tr><tr><td><p dir="ltr">BIO15: Precipitation: seasonality (coefficient of variation of monthly precipitation; Standard deviation of BIO12/mean of BIO12 * 100)</p></td></tr><tr><td><p dir="ltr">BIO16: Precipitation of wettest quarter (mm)</p></td></tr><tr><td><p dir="ltr">BIO17: Precipitation: driest quarter (mm)</p></td></tr><tr><td><p dir="ltr">BIO18: Precipitation of warmest quarter (mm)</p></td></tr><tr><td><p dir="ltr">BIO19: Precipitation of coldest quarter (mm)</p></td></tr></table><p><br></p>