Unit 2 - The Forest Ecosystem

Lesson 2: Climatic Factors


Sunlight, temperature, wind, and precipitation play major roles in determining where trees and plants live. For example:

  • Aspen and birch trees like a lot of sunlight. They don't grow well when shaded by taller trees. These trees tend to become established very quickly in areas that have been cleared of other trees by forest fires.

  • Aspen and birch would not likely be found in shady temperate rainforest where wet conditions do not allow for forest fires.

Temperature, wind, and precipitation are also key factors that affect forest development.




Canada's northern forests are characterized by long, dry, very cold winters and short, moist, cool summers. Therefore the type of forest that grows here is mainly coniferous. This is because coniferous trees are especially adapted to the harsh climatic conditions:

  • The conical needles of coniferous trees have a waxy coating and a small surface area, thus reducing water loss.

  • These needles remain on the tree year round allowing the tree to photosynthesize even during the winter time.