A tree, a perennial plant with a lignified, erect stems, the stem. A more detailed or clear definition of this “life form” is difficult to give due to the variety of sizes and appearance of plants that are called trees. Even a banana, for example, is often considered a tree, although the stalk is herbaceous. Sometimes in the definition of a tree, it is especially emphasized that its trunk is consistently divided into ever more delicate branches or that the tree has a clear, lobed crown. However, the trunks of most palms do not branch at all, and in giant cacti the lignified trunk, if it carries lateral branches, does not crown with any crown.
Many definitions set the minimum height of the plant, which can be called a tree, but for different authors, this figure varies from 2 to 6 m. Sometimes this life form is ascribed to the whole species, and in other cases – only to certain instances of a specific taxon. So, creeping plants in high mountains or the Arctic can be called trees, because, under more favorable conditions, representatives of this species are erect and quite high. In other cases, the plant does not exceed a few decimeters in height, for example in a nursery or in a decorative dwarf form created by a school of bonsai, but for all other characteristics, it corresponds to a tree. All specimens corresponding to the mature state to the classical wood tree begin their natural development from a seed or a tiny vegetative sprout. In this connection, the question arises:
For some purposes, rather rigid definitions may be required, but in general, the term “tree” assumes a wide range of interpretations.
Trees and shrubs.
The vagueness of the concept “tree”, obviously, generates and indistinctness in the delimitation between the tree and another group of erect stony plants – shrubs. It is believed that the latter always have several trunks, among which it is impossible to single out the main one unambiguously. The height of shrubs rarely exceeds 3 m, although there are eight meters among them. In general, species traditionally considered shrubs rarely encounter “tree-like” specimens, but exceptions are known in such genera as, for example, sumah, alder, irga, cercocarpus, dogwood, willow, elder. At the same time, very many species, classified as typical trees, can give shrub forms. Some trees, if cut or burned, form a root or stump, which eventually develops into a large plant with several trunks, among which it is not always possible to indicate the main one. Nevertheless, in this case, it would be more logical to speak not of a bush, but of a multi-stem tree. By the way, if there are many such trees in the forest, it is likely that it was cut down or burned.
Trees grow on a significant part of the land, as well as in small areas of fresh and salt water. They are absent in the circumpolar regions, high mountains and extremely arid places. In the Western Hemisphere, the range of this life form extends from McKenzie Bay in western Canada about 14.5 thousand kilometers south of Tierra del Fuego. In the Eastern Hemisphere, trees grow from the Taimyr Peninsula in Russia to the New Zealand island of South, between which along with the meridian of approx. 13 thousand km. See also PHYTOGEOGRAPHY.
Sizes and age.
Trees are the largest and the longest living of modern organisms. The size record holder is a Sequoiadendron (mammoth tree) “General Sherman” from the Sequoia National Park in California. In 1975 the height of this tree was 84 m with a stem base diameter of more than 11 m. At an altitude of 37 m, the trunk was 5 m thick, and the lowest branch, extending from the trunk at approximately 40 m, had a length of 46 m with a diameter of 2.1 mOne branch is larger than many other species of trees. The volume of wood in this specimen is approx. 1400 cube. m – enough to cover the parquet with a thickness of 30 cm the whole football field.
In second place is another Sequoiadendron – “General Grant” from California’s Kings Canyon National Park. According to the latest measurements, its height is 81.5 m, the diameter of the base is 10.2 m, and the volume of wood is 1219 m3. m. On the western slope of the Sierra Nevada (California), hundreds of sequoia-dendrons with a height of 60-90 m grow.
The six tallest trees in the world are sequoias, close relatives of mammoth trees. The champion among them grows in the Redwood National Park in California. According to recent measurements, its height is 111 m with a base diameter of 4.3 m. The former champion was about 0.3 m higher in 1955, but his wind broke the summit.
According to rumors, there are even higher – up to 120 m – giants. Today, live Douglas above 100 m are unknown, but in 1900 a specimen of this species 116 m high was allegedly felled. Travelers report the giant Australian eucalyptus, however, the height of the largest measured species of this genus, the eucalyptus Dalrymple, cut down near Kolas in Victoria, was “only “105 m, and in another specimen, still growing near Melbourne, it is not more than 99 m.
The thickest known tree is the taxodium, or marsh cypress, growing in the small town of Santa Maria del Tula near Oaxaca in Mexico. The diameter of the base of its trunk (probably formed by several fused trunks) is 11 m. To embrace this tree, it is necessary to put around 20 people around him with arms outstretched. In the baobab on one of the islands near Java in the Indian Ocean, the diameter of the trunk is 9 m, in agates from New Zealand, on the west coast of the United States and a number of other species, it reaches 6-7.6 m. Another record is recorded in the west of India, where it grows Banyan (Ficus Bengali), which has 350 large trunks and 300 smaller ones. Together they occupy the site with a perimeter of 600 m, i.е. an area of approx. 2.8 hectares.
From different regions, it was reported about the finds of very ancient trees. For example, the age of some microsomes in Australia was estimated at 12,000 years, but these crocheted ones do not form annual rings, so it is impossible to verify the accuracy of the proposed dating. It is estimated that the Californian Sequoiadendron survive to 5000 years, but the number of rings they have actually counted does not exceed 3200. The life expectancy of African baobabs is believed to be ca. 4000 years, and Indian banyans – approx. 3000. An officially recorded record belongs to the line durable. Approximately 20 trees of this species age over 4000 years grow at a height of approx. 3000 m above sea level in the mountains of White Mountains in the east of California, one of which is about 4600 years old. Another group of very ancient durable pines is known on Mount Wheeler Peak in Humboldt National Park (Nevada).
Source: wooden designs