Part 12
Pine is one of the most common trees in our country. It grows on a vast territory - from the White Sea to the Black Sea and from the western to the eastern borders of the USSR. This tree is very unpretentious to the soil. Pine can be seen on dry sands and mossy bogs, on bare chalk slopes and on granite rocks. But it is very demanding in terms of light and does not tolerate shading at all. It is one of our most light-loving tree species. Like other light-loving trees (birch, larch, pine trees have a loose, openworked crown that lets in a lot of light.
In the structure and reproduction of the pine many interesting things.
Pine needles are long and narrow, they are always collected in pairs. The pairs of pine needles are a characteristic feature of this tree species. After extinction, both needles remain connected and fall together. Look at the ground under the pine tree - you will definitely find these "twins". Dry pine needles fall off in September. Shortly before that, in August, a kind of "motley" can be seen in the crowns of pines: some of the needles are green and some are yellow.
All year round we see pine in its unchanged green dress, even in winter it looks like in summer, its green needles are not afraid of frost. And what is the danger of frost for pine needles? Of course, not by the fact that the water in them will turn into ice. There is no way to avoid it. Danger is another - drying out.
But in winter pine needles are reliably protected from drying out. Each needle is covered with a thin but impermeable cuticle film on the outside. The microscopic valves are tightly closed, with many needles scattered over the surface.
Pine - evergreen tree. But every spring it has buds and young shoots, as well as deciduous trees. Take a closer look at the pine branches in spring. Here are the old shoots with normal needles - long and dark green. And at the ends of their growing young shoots. They are light green. There are no real needles on them yet.
At the base of the young shoots there are dense light yellow bunches of the so-called male cones. Each cone is smaller than a pea. It will take some time, and yellow pollen will fall abundantly out of them. Pine produces a huge amount of pollen. It is spread by the wind in a pine forest when the trees are "dusting".
In spring, you can also find female cones at the ends of young pine shoots. They look like tiny kernels a little larger than a pinhead. They are not immediately noticeable among the surrounding young needles. Usually there is one cone at the end of the escape. Each of them has a long way to go before becoming an adult. It takes about two years. In the first year, it hardly grows: by autumn, it is no more than a pea. In the second year, it increases in size and by the winter it finally forms - it becomes brown and becomes a village. By this time, the seeds have matured.
But the seeds only fall asleep from the cones the next spring, after the snow melts. The seed itself is like a millet grain, but it is equipped with a small film wing. Having fallen out of the cone and found itself in the air, the winged seed begins to rotate very quickly, like a miniature propeller. This slows down its fall and the wind can carry the seed away from the mother tree.
Pine seedlings are very original when they have just emerged from the seed. They are small plants with a stem shorter than a match and no thicker than a regular sewing needle. At the top of the stem is a bundle of very thin needles-semyadols, radially diverging in all directions. Pine seedlings have not one or two seedlings like flowering plants, but much more - 4-7.
With sufficient access to light, tiny shoots turn into small pine trees in a few years. These young pine trees already have a visible trunk, and the branches are covered with ordinary needles, arranged in pairs. Young pine trees are several metres tall if they grow in full light in the open.
Young pine trees (teenagers) in pine forests are difficult to find - they are very few. The reason for this is that pine trees are very light-loving.
The pine tree is surprisingly unpretentious to the soil conditions. It can tolerate extreme poverty of soil nutrients, extreme dryness and extreme lack of oxygen. In this respect, no other tree species can be compared to pine trees. Special experiments have shown that young pine trees can grow for several years without nitrogen compounds from the soil.
Pine is a valuable tree species. It gives an excellent building material, beautiful firewood. From its resin produce a lot of essential substances for humans. And how great is the health-improving value of pine forests! These forests need to be protected, preserved.
The continuation should be...