The tree is a woody perennial. This is the most common definition for woody plants, there are many secondary branches supported clear a main stem or trunk on the ground there is a clear apical dominance. The minimum height specification mature quoted from three to six meters; some set a minimum trunk diameter of 10 cm (30 cm circumference) in woody plants do not meet the these definitions have multiple stems and / or small-scale known as the bush. Compared with most other plants, trees are long-lived, and some thousands of years old, an increase of up to 115 meters (379 feet) high.
The tree is an important part of the natural landscape, because they prevent soil erosion and weather, sheltered ecosystem, and in its branches. They also play an important role to produce oxygen, reduce carbon dioxide in the atmosphere, as well as easing the ground temperature. They are also elements in landscaping and agriculture, both for their aesthetic attractiveness and orchard crops (such as Apple, Cypress
The wood from the tree is the main source of energy for a building material, as well as many developing countries.
The main four parts of the tree structure tree root, stem, branches, leaves. Roots generally in the ground, in the bottom of a tree root. Tree stem, including support and transport tissue (xylem and phloem). Wood xylem cells, the bark are the phloem and other organizations outside the vascular cambium. Consists of five in the trunk section. The first layer of bark. The bark is the surface of the trunk, you can protect the tree trunk and prevent disease invasion. Below the bark is the phloem. This layer of fibrous organization of sugar transported from the leaves down. The third layer is the cambium. This layer is very thin, and the growth part of the trunk, all other cells are layer has since come. The fourth layer is the sapwood. This layer is transported to the water from the roots and trunk throughout this layer is usually more heartwood light-colored. The fifth layer is the heartwood. The heartwood is old sapwood, both collectively known as the xylem. Trunk were mostly heartwood.
The tree form has evolved in unrelated classes of plants in response to similar environmental challenges, making it a classic example of parallel evolution. With estimated at 100 000 tree species, the number of tree species worldwide might total of 25% of all biological plant species. Most of the species growth in the tropical regions of the world, many of these places and there is no investigation has not yet been a botanist, so little is known about species diversity and scope. Tree ferns, horsetails and lycophytes, it grows in the forests of the Carboniferous period, tree ferns still survive, but the only surviving horsetails and lycophytes are not in the form of the tree. Later, in the Triassic Period, conifers, Ginkgo, cycads and other gymnosperms appeared, followed by flowering plants during the Cretaceous period.
A small group with the growth of trees is known as a forest or coppice and landscape covered with a dense growth of trees and a forest. Several habitats mainly by the trees they inhabit; examples of tropical rainforest and taiga (see ecological zones). A landscape of trees scattered on the grass or interval (usually grazing or burning more than regularly) is called a savanna. A great era of forest known as the old forest or woodland. A young tree is called seedlings.
The functions of tree in the earth are as following:
(1) Reduce the temperature of the woods
Walking under the hot sun, see the shade of a tree, it is natural will go past shade. Because most of the sun will be the crown block, and absorb as transpiration and photosynthesis, the temperature is lower under the tree.
(2) Increase in the woods humidity
In the dry autumn and winter, trees growth needs moisture to transpiration released in the atmosphere. This will increase the humidity in the air, so that people feel comfortable and more.
(3) Air exchange
In the same environment, the forest because the trees absorb large amounts of sunlight, temperature lower than in the cities, so that lower and moderate compared with high temperature air cycles with each other, so they can ease the urban temperature rise speed.
(4) Slow down the wind speed, blocking the wind
The dense canopy can reduce wind speed, the airflow in the dust grains of sand fell on the ground. Leaves the surface of the hair and sticky grease, can absorb the dust in the air. If we pay attention to international news, or heard woods can slow down the invasion of sand.
(5) Noise walls
Trees can absorb noise. The trees wave scattering, acoustic swing through the branches and leaves gradually weakened to disappear.
(6) Air Purifier
Trees can reduce the concentration of bacteria in the air. Poplar, birch, lemon eucalyptus release of spinosad, can kill bacteria pneumonia, dysentery bacillus, diphtheria bacteria, etc..
(7) Fire resistance
Difficult to burn the wood of certain trees, such as the resin is less water and more trees, does not produce a flame was ignited such as Ternstroemiaceae, camellia, Podocarpus, to prevent fire from spreading quickly. In addition, the canopy of large trees can block sunlight into the ground to prevent the growth of shrubs to reduce the hill fire combustion of materials.
There are two sources either biological damage to the trees (from the source of life) and abiotic (non-biological source). Biological sources, including insects bore into the tree, deer rub the bark off, and fungi.
The non-biological sources, including lightning, the impact of the vehicles, and construction activity. Damage by the construction activities may involve a number sources, including changes in the level of prevent aeration root, leakage of toxic chemicals, such as cement or petroleum products, or cut off a branch or root causes.
These two sources of damage can lead to trees become dangerous, the so-called "dangerous tree" by arborist. Harm the trees due to illness, storm, or other factors. Normally, people use three methods to reproduce tree, they are seeds, cutting and grafting.
The global warning and fire harm forest, giving us the notice to take action saving the earth. Therefore, we have to protect tree, trees give us the oxygen and let us alive. Please save the earth, help the nature and us, we can plant a tree, protect and love them. Making the earth more beauty and living well.
Tallest Tree
Oldest Tree
ScienceDaily as at (Apr. 16, 2008 ) reported the world's oldest recorded tree is a 9,550 year old spruce in the Dalarna province of Sweden
Tallest Living Tree
The tallest tree in the world is a coast redwood (Sequoia sempervirens), named Hyperion after a person in Greek mythology. The tree is no less than 115.55 m (379.1 feet) tall! This enormous tree was discovered only in August 2006 in a remote part of the Redwood National Park, California by naturalists Chris Atkins and Michael Taylor.
The tallest tree in the world is a coast redwood (Sequoia sempervirens), named Hyperion after a person in Greek mythology. The tree is no less than 115.55 m (379.1 feet) tall! This enormous tree was discovered only in August 2006 in a remote part of the Redwood National Park, California by naturalists Chris Atkins and Michael Taylor.
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