In autumn, the crowns turn red, yellow and orange, and then the leaves fall off – thus adapting to the cold weather. But why is this not the case for conifers and how do they survive the cold weather?
Evergreen trees do get rid of their needles, but it takes a year. In 12 months, a Christmas tree can change about 80 per cent of its needles. In addition, they are narrow and long: if snow accumulates on them, it is only a little, and it does not weigh down the branches.
In addition, the needles do not need a lot of sunlight. The reason is size: the smaller the leaf (and a needle is a leaf), the less sunlight it needs for photosynthesis. Because the needles are small, photosynthesis is quite fast and chlorophyll is produced. Where chlorophyll is present, green colour is also present.
