Why do pine trees keep their leaves in winter?

Why do pine trees keep their leaves in the winter?You probably have noticed that the trees that keep their leaves through the winter--like the pines, spruces, and firs--have special leaves that are like tough little needles. These have a lot less water than the thin flat leaves that fall from other trees in autumn

Those needlelike leaves of the pine tree also have a special ability to stand below-freezing temperatures without damage. Most organisms that can do that have some special "antifreeze" chemicals.

Scientists are learning more about these. The big danger of freezing is the formation of ice crystals, which push right through cell membranes and kill the tissue. Some of the "antifreeze" chemicals work to prevent the formation of ice crystals. I think that's a neat trick.