Soil Temperature Class Codeset


Code Definition
ARCTIC Extremely Cold
BOREAL-C Cool
BOREAL-MC Moderately Cool
CRYOBOREAL-C Cold
CRYOBOREAL-MC Moderately Cold
MESIC-M Mild
MESIC-MW Moderately Warm
SUBARCTIC Very Cold
THERMIC Moderately Warm to Warm

Expanded Definitions

Arctic Extremely Cold

  • Mean annual soil temperature < -7 °C
  • Mean summer soil temperature < 5 °C
  • Growing season >= 5 °C, < 15 days
  • Thermal period >= 15 °C, none
  • Regions in this class have continuous permafrost usually within a depth of 1 m.

Subarctic Very Cold

  • Mean annual soil temperature -7 °C to < 2 °C
  • Mean summer soil temperature 5 °C to < 8 °C
  • Growing season >= 5°C, 120 days
  • Growing season degree-days >= 5 °C, < 555
  • Thermal period >= 15 °C, none
  • Regions in this class have widespread permafrost. Some profiles do not have permafrost within a depth of 1 m. Alpine soils are included in this class.

Cryoboreal Cold to Moderately Cold

  • Mean annual soil temperature 2 °C to < 8 °C
  • Mean summer soil temperature 8 °C to < 15 °C
  • Soils with aquic regions may remain frozen for portions of the growing season. Organic soils having discontinuous or localized permafrost should be classified as Moderately Cold.

Cryorboreal Cold

  • Growing season >= 5 °C, 120 to 180 days
  • Growing season degree-days >= 5 °C, 555 to < 110

Cryoboreal Moderately Cold

  • Growing season degree-days >= 5 °C, 1110 to < 1250

Boreal Cold to Moderately Cold

  • Mean annual soil temperature 5 °C to < 8 °C
  • Mean summer soil temperature 15 ° to < 18 °C

Boreal Cold

  • Growing season >= 5 °C, > 170 days
  • Growing season degree-days >= 5 °C, 1250 to < 1388
  • Thermal period >= 15 °C, < 60 days

Boreal Moderately Cold

  • Growing season >= 5 °C, < 220 days
  • Growing season degree-days >= 5 °C, 1388 to < 1720
  • Thermal period > 5 °C, < 120 days

Mesic Mild - Moderately Warm

  • Mean annual soil temperature 8 °C to < 15 °C
  • Mean summer soil temperature 15 °C to < 22 °C

Mesic Mild

  • Growing season >= 5 °C, 220 to 240 days
  • Growing season degree-days >= 5C, 1720 to 2220
  • Thermal period >= 15 °C, < 120 days

Mesic Moderately Warm

  • Growing season >= 5 °C, < 240 days
  • Growing season degree-days >= 5 °C, 2220 to 2275
  • Thermal period >= 15 °C, > 180 days