All of us we are in the woods. What is hidden under the name of "forest"? Lots of trees – this is the forest, give some definition, a lot of trees that are suitable for preparation of drill and saw logs logs and other forest called, the third is meant by a forest is not only a lot of trees, but all the trees and grass in the area occupied by trees, including a fourth the term "forest" but all the plants and insects, birds and animals, constantly living in the forest.
Acquainted with the signs of the forest.
Trees in the forest are different in appearance from the tree of the same species grown in the park, in the field and all the trees that grow in freedom.
Tree from seed germination to the dying is attached to one place. The area of land occupied by them at an early age, becomes a disadvantage as it grows. Each tree light is needed. Striving upward to the sun, the trees are catching up, and distilled each other in growth, shade weaker, condemning them to dry out. So thin trees in a forest, but the high, live branches are located in the upper third of the trunk. Tree trunk in appearance and volume close to the cylinder.
In the park, the park, the avenue trees have no shortage of light, they are pulled high, they have a wide, sprawling, low located crown, trunk, thick at the bottom, it becomes thinner to the top and form closer to the cone.
Thus, the extent of the forest stand density vary the shape and size of the crown, shape, thickness and height of the tree trunk, and the rate of extinction of the lower branches, remained without electricity as tree growth and development of their crowns.
Observant person will notice the difference and the trees in the forest height and thickness of the stem and crown development. In some cases this is due to differences in age, for example in the pristine, untouched by man of the woods. But in the vast majority of it is a product of trees and their individual characteristics even at the same age. You may notice that some of the trees ahead of the height and thickness of the trunk and the development of the rest of the crown, while the majority of trees a little behind the first, and are a major part of the forest, and their well-developed crown form its upper canopy.
In between the crowns of the dominant tree canopy are trees that crown or squeezed at the sides, and there was only one side of a national flag. These trees, participating in the upper canopy, experiencing oppression by more powerful neighbors. Under this general canopy of some trees on the brink of extinction, with each year from lack of light and food, they are doomed to hireyut shrinking, even the trees that towered above the upper canopy is not fully utilized, soil nutrients, – some of them have stunted and then dead trees.
Foresters, based on the appearance of the crowns, distribute trees in the forest of the most powerful to the most frail, but alive, into five classes and subclasses. I belong to the class of the best trees for the growth and development of the crown and to the V class – the most backward. This classification reflects the gradual dismemberment of the original, at a young age, the same trees in terms of their development.
At an early age the population density of the area occupied by the tree is very large, one-year, two-year de revtsev per hectare could be 20, 100 thousand or more, and at the ripe age of the forest to remain 100-120 600-1,000 trees. In the Leningrad region in different soil fertility the number of trunks of pine at 20 years of age per hectare varies between 5-6.5 thousand, and the 140 years left on the vine 460 – 650 trees.
Even greater Otpad observed in beech forests: in the age of 10 the number of trunks per 1 ha of 100 – 850 thousand, and the 120 years is only 500-750 trees.
Minimal need for space is different for different tree species and ages. The most light-requiring and requiring more space for yourself is pine: spruce content with 87% of this area, beech – 79%, and fir – only 63%. Need to eat in the minimum area for the normal life of 20 years 0.4m2, at 40, 60, 80 and 100 years, respectively – 3.2, 6.5, 10.3 and 14.1 m2.
Space requirements for each tree increases with age, and the total area occupied by the trees, remains unchanged. A similar, the situation worsen with age leads to mutual rivalry trees. Young trees, lagging for some reason, its neighbors in growth (from the ax wound, a broken top, broken branches or bad heredity) face oppression. Healthy neighbors, clutching the tree canopy of the oppressed, it reduced the supply of light, and therefore reduced and the formation of organic matter coming for root development. Poor development of roots, pressed by more powerful neighbors back on top, reduce intake of inorganic substances from the soil for the development of the crown, and the tree dies. Circle.
Luminary of Russian forests, the founders of the forest, Morozov is the main event in the life of the forest is characterized as follows. With increasing age of trees to increase their size, they occupied the same area remains constant. Since the tree must develop not only up, not only into the soil with their roots, but also to the sides, then very soon they become close. Those who are endowed with greater individual force growth or took a few better places than their neighbors, because the soil environment was not completely uniform, or, finally, because in the event of accidental forest because of the uneven distribution of natural regeneration they are lucky to have a large space of land and atmosphere than their neighbors, develop faster and better by dominating others. "There is, – said in conclusion Morozov – a real struggle for existence in a literal, not a figurative sense, end up winning one and losing the other."
The root system of different breeds are different – a powerful and far-extending deep into the pine, cedar, oak, and the surface – of spruce. Therefore, some wind resistant tree species, others are easily windblown, but there could be variations. For example, the pine, growing in the swamp, the root system is shallow, because its roots are experiencing lack of oxygen in the water, spread over bumps.
Mutual influence of the trees changing not only the look and the level of development, but also determines the amount of seed yield of each. If I take the productivity of trees in the adult class of spruce forest in yield (seed) for the year 100, in class II yield was 88%, class III 37%, in the IV – only 0.5%, and the trees are a class V completely sterile, though all the trees of the same age class. Thus, in the preparation of the future of the forest is the natural selection of primary source material – the highest amount of seed yield better development trees.
During the existence of the forest in the world changed for many generations of a breed. Natural selection leads to a kind of self-improvement in certain prevailing conditions for thousands of years without human intervention. Multilateral cooperation in forest trees is already stable compound of trees. If any part of the forest area affected by fire or windfall, then it must be through a period of time will be planted seeds to nearby trees.
Features forest life rooted in the variability of an individual organism, from the seed, and in the hereditary qualities that are inherent in it the germ cell.
Mature seeds in the forest is always more than enough for germination and sprouting of many, but not all the young plants grow to such a height that they can be seen at first view. Samos, or undergrowth – the younger generation, the technology to replace the old, in greater or lesser quantities can be found in any forest.
In a dense undergrowth of the forest canopy grown uneasy existence. Shoots, which turned on the edge, the clearing, in areas where gaps in crowns, formed after Tipping old tree gets enough light to grow well. Such plants branches begin from the ground, they are densely covered with leaves or needles of bright green color, the top of their well-developed.
Under the cover of a spruce or pine wood, there are many young trees or pine trees that have fallen into such fortunate conditions, and they have to be satisfied with what they got. And they got very little. Usually adolescents growing groups concentrated in conditions favorable for germination and initial growth period of shoots. But as the group begins rivalries within regrowth, in addition, the upper canopy of trees shaded adult wood, and they have to be content with the remnants of the light that came through the trees of the older generation. The roots of saplings develop in the soil, the root system is already busy old forest, and they have to be limited to less food and water. Often seen in dense spruce forest undergrowth in that the one-firs, aged 30-50 years. Photophilic pine under the thick canopy of the mother before this age do not live and die much earlier.
The oppressed undergrowth almost imperceptible apical shoot, branches are only in the top of the stalk and arranged horizontally – so more light reaches them.
In the natural forest with old trees dryahleyut years, gradually falling out at different times and increasing gaps between trees. More light, more moisture in the wood – less competition among the younger generation with the root system of the parent timber. Undergrowth recovers, adapts to new conditions and accelerates growth, wedging peak in the upper canopy. Even after 80 100 years of oppression spruce can recover and join the upper canopy.
But if depressed adolescents immediately put to a public place, that is to cut down all the old trees surrounding it, in most cases, trees saplings die: their needles adapted to work with a small access light turns yellow and fall off. Foresters felled trees prevent regrowth gradually until replaced by the tree foliage, which is usually 3-4 years. The chlorophyll content and the intensity of his work are different for different species and even within the same tree, for example on the top and on the lower branches, due to different lighting conditions. Undergrowth different species growing in different ways under the forest canopy.
The same shade tolerant spruce grows quite well under the canopy of light-requiring birch and competes with it. Being durable birch, he catches up in growth, and then surpass in height, obscures its thick needles and by accelerating the death of his adopted birch forest.