In fact, needles are tightly rolled leaves. And like them, they are responsible for photosynthesis
and therefore for the «transformation of nutrients» for the tree.
During this process, in addition to the oxygen released, a large amount of aqueous
vapor escapes from the stomata of the leaves (or needles). As the surface area of
is much smaller than that of the leaves, transpiration is reduced.
On their underside, the needles also have special «stoma cells» which are buried in a
small cave and slow down the evaporation of water even more.