Needles on evergreen trees of the taiga are thin and wax-covered. They do not fall off in the fall. 

Needles are leaves. Most taiga conifers, with the exception of the tamarack and a few other species, keep their leaves in the winter. Most conifers keep their leaves for 2 - 3 years. A spruce can keep its needles for 15 years! Conifers lose their leaves a few at a time, so the change is not always noticeable. 

Needles are adapted to the taiga environment. Needles lose less water and shed snow more easily than broad leaves.