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Question 18N.2.HL.TZ0.4b

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Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.2.HL.TZ0.4b
Level HL Paper 2 Time zone TZ0
Command term Suggest Question number b Adapted from N/A
b.
[Maximum mark: 2]
18N.2.HL.TZ0.4b

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.

(b)

In some areas there are gaps in the boreal forest where trees fail to grow and peat tends to accumulate. Suggest reasons for this.

[2]

Markscheme

a. waterlogged soils/poor drainage
OR
acidic soil
OR
anaerobic conditions/soil ✔

b. organic matter not «fully» decomposed «leading to peat formation»
OR
decomposers/saprotrophs less active/fewer in cold «temperatures» ✔

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