Map of Bioclimatic Subzones & Boreal Forests

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Map: Bioclimatic subzones, boreal forests and forest tundra.

  • Bioclimatology: branch of climatology that deals with the effects of the physical environment on living organisms over an extended period of time.
  • Boreal forest or Taiga: a biome characterized by coniferous forests consisting mostly of pines, spruces, and larches.
  • Forest tundra: Areas of transition from forested to non-forested landscapes. At high latitudes, north of the main zone of boreal forestland, growing conditions are not adequate to maintain a continuously closed forest cover, so tree cover is both sparse and discontinuous.

You can use the map freely, provided that the sources are credited.

Sources

Bioclimatic subzones

1. Subzone A (Coldest, High Arctic)

  • Summer Warmth Index (SWI): < 6°C (sum of mean monthly temperatures > 0°C).
  • Growing Season: Very short (1–2 months).
  • Vegetation: Sparse, dominated by cryptogams (lichens, mosses), cushion plants, and bare ground.
  • Example: Northern Greenland, central Arctic Ocean ice margins.

2. Subzone B (High Arctic)

  • SWI: 6–9°C.
  • Growing Season: Slightly longer than Subzone A, but still limited.
  • Vegetation: Low-growing vascular plants (e.g., Arctic poppy, saxifrages), lichens.
  • Example: Northern Svalbard, Canadian High Arctic.

3. Subzone C (Middle Arctic)

  • SWI: 9–12°C.
  • Growing Season: Moderate (2–3 months).
  • Vegetation: Dwarf shrubs (e.g., Arctic willow, Dryas), grasses, sedges.
  • Example: Northern Alaska, central Nunavut.

4. Subzone D (Low Arctic)

  • SWI: 12–20°C.
  • Growing Season: Longer (3–4 months).
  • Vegetation: Continuous tundra with taller shrubs (e.g., birch, willow), moss/lichen understory.
  • Example: Northern Scandinavia, Siberian tundra.

5. Subzone E (Warmest, Subarctic)

  • SWI: > 20°C.
  • Growing Season: Longest ( >4 months).
  • Vegetation: Transition to boreal forest (taiga); dense shrubs, scattered trees (e.g., spruce, larch).
  • Example: Southern Yamal (Russia), Labrador (Canada).