Gymnosperms, Such as Spruces, Often Dominate High-Latitude Boreal Forests, Whereas

Multiple Choice

Gymnosperms, such as spruces, often dominate high-latitude boreal forests, whereas angiosperms dominate rainforests because tracheids:

A) are less susceptible to freezing-induced cavitation than vessels, but less efficient for moving large volumes of water.
B) do not freeze as easily as vessels, maintaining flow to support photosynthesis at colder temperatures, which is not an advantage in the tropics.
C) mature more quickly than vessels, allowing gymnosperms to make more efficient use of the shorter growing seasons of boreal forests.
D) better withstand the large tensile forces required to extract water from frozen soils than vessels, but offer no advantage in warm tropical soils.