Why is evaporation from plants limited in the tundra?

Question

Why is evaporation from plants limited in the tundra?

Answer 1

For much of the year the ground is frozen, so the water isn't available to the plants.  The temperatures also limit the length of the growing season, and plants need the most water when they're using photosynthesis to produce food for themselves.

And since the tundra tends to occur nearer the polar regions, remember that the tilt of the Earth's axis means that there's no sunlight at all for several months of the year if you're above the Arctic circle (reduced light if your to the south of it).