IB Biology SL 4.3.3 Boreal forest tipping point Question Bank
Practise IB Biology SL 4.3.3 by explaining how warming increases drought, fire and stress in boreal forests.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Practise IB Biology SL 4.3.3 by explaining how warming increases drought, fire and stress in boreal forests.
Boreal forests stretch across Canada, Russia and Scandinavia. This northern ecosystem accounts for 29 % of the world's forest areas. The long, cold winters favour tall evergreen trees with either needles or scale-like leaves. These trees are wind-pollinated and their seeds are not enclosed in a fruit. The photograph shows a typical boreal forest in winter.

An increase in global temperatures poses a critical threat to boreal forests. Explain the consequences of climate change to this northern ecosystem.
Higher temperatures so more transpiration/droughts/dehydration/water shortage.
More forest fires.
More/new pests/diseases because of the changed conditions.
Competition from trees/plants that colonize/spread to boreal forests.
Trees/named organisms of boreal forests not adapted to warmer conditions.
OR trees/named organisms migrate/extend range due to the warmer conditions.
Trees die so there is loss of habitat for animals.
Faster decomposition/nutrient cycling so conditions in the ecosystem change.
Standing water/floods due to more snow/permafrost melting.