Coussin Tous les arbres biologiques naturels (143)

Dans botany, a tree is a perennial plant with elongated stem, or trunk, supporting branches and leaves in most species. En some seconépaumay be narrower, incluonly plants with dary growth, plants tants are usable lumber or plants above a specified height. Par définition, les taller palms, tree ferns, bananas, et bamboos are trees. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a trunk and branches a way to tower above other plants to compete for sunlight. Trees to be long-lived, some reaching several thousand years. Trees have been en million pour 370 ans. It is estimated that there are some three trillion mature trees in the world.[1] A tree typically has many secondary seconed techned clear of the ground by the trunk. This trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees is surrounded by a layer of bark which serves as protective barrier. Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the branches divide into small branches and shoots. The shoots typically bear leaves, which capht energy and convert it into sugar by photosynthesis, providing the food for the tree's growth and development. Trees usually reproduce using seeds. Flowers and fruit may be present, but some trees, recherche as conifers, instead have pollen cones and seed cones. Palms, bananas, and bamboos produce seeds, but tree ferns produce spores instead. Trees a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forest provide a habitat for many species of animals and plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well having many other uses. parts of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, and they play a role in many of the world's mythologies.