Evergreen plants are so widespread that not everyone even thinks: and what has caused their such natural property. Nevertheless, the set of processes is involved in providing fir-trees and pines in winter season.
Seldom which of people, with ease solving unpretentious children's riddle "in the winter and in the summer in one color", thought: and why really so occurs in the world of the nature that coniferous trees – fir-tree and pine – evergreen? No, why green, clear. All remember from school lessons of biology such natural pigment of green color as chlorophyll which is one of the main participants of process of photosynthesis, or as speak, "breath" of plant.
As photosynthesis works
Leaves absorb carbon dioxide from air, through root system water and mineral salts gets to them. The chlorophyll under the influence of light transforms the ingredients received from the outside to glucose which is the main food of plant. For elaboration of power supply for plant there is only insignificant quantity the deliverable root system of water, its main weight evaporates through the same leaves.
In cold season when the earth freezes, the tree cannot receive enough water any more, and in order to avoid excessive evaporation of moisture through foliage surface, is forced to dump the last. The fir-tree and pine do not feel such need. In essence, needles of these trees are leaves. They are rather thin, are covered with the wax dense cover that minimizes percent of the moisture evaporated by them. The tree leaf form in the form of needle allows to balance as much as possible process of receipt and evaporation of moisture tree in winter time. Photosynthesis process in that case becomes constant.
Needles - surprising kind of leaves
It would be incorrect to consider that needles on pine or fir-tree do not fall down. It is enough to walk on the forest or the park to make sure of inaccuracy of the similar assumptions. All focus that the needles which have become obsolete the term, falling down, are at the same time replaced with new. Thereof the tree has constant steady green coloring of the leaves needles. It is worth noticing that replacement of needles on tree happens on all branches at the same time not at once. This process goes gradually and measuredly. Falling off of needles can happen at different types of pine or ate with different frequency. The minimum term of life of hvoinka it is considered to be twelve months. More frequent dropping needles says that with tree not everything is all right. The needles at the majority of species of fir-trees do not fall down till several years, and the champion can be considered so-called pine awned which needles keep on tree up to 43-45 years.