What type of forest stays green all year

Boreal forests often get less rain than the other forests and are home to evergreen trees, which stay green all year long. This is because they have needles, which don't need as much water as regular tree leaves.

I agree with the answer above - boreal forests are the kind of forests that remain green all year, because evergreen trees can be found there. Opposite of this, temperate forests do not stay green all year, because they have deciduous trees, which means their leaves fall off.