Climate & Treeline Facts

Factors that contribute to the Arctic Tree Lines

Located at 61 ° latitude, -99° longitude.

Polar treelines are heavily influenced by local variables such as:

  • Aspect of slope and degree of shelter, meaning the direction that the trees are facing: toward the wind, away from wind, towards a valley, over a lake, etc.
  • Permafrost (soil or rock that remains below 0°C or 32 °F throughout the year, and forms when the ground cools sufficiently in winter to produce a frozen layer that persists throughout the following summer) has a major impact on the ability of trees to place roots into the ground. When roots are too shallow, trees are susceptible to windthrow and erosion.
  • River Valleys: Trees can often grow in river valleys at latitudes where they could not grow on a more exposed site.
  • Ocean currents: Maritime influences also play a major role in determining how far north trees can grow.

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