| Suggest two environmental factors that enable pine trees to photosynthesise in spring and summer in Switzerland, but not in winter.

The  two environmental factors are Temperature and light

The following information should be considered:

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Temperature and light

Explanation:

In winter, day length is shorter than in spring/summer and the sun does not rise as high in the sky. There is also more cloud cover, fog and snow to reduce access and intensity of light.

Colder temperatures reduce metabolic activity, and at temperatures below zero, water uptake is prevented, which reduces transport of nutrients, and icing of needles and snow cover reduce access to carbon dioxide.

In spring/summer sunlight is more readily available, temperatures more conducive to carbon dioxide uptake and transpiration.