A forest is an area of land dominated by trees. There are hundreds of definitions of forests used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations Food and Agriculture Organization (FAO) defines a forest as "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban use". Using this definition, forests covered approximately 31 percent of the worlds land area in 2020.
Forests are the largest terrestrial ecosystem of Earth by area and are found around the globe. They can occur wherever the temperatures rise above 10 °C (50 °F) in the warmest months and the annual precipitation is more than 200 mm (8 inches) . Forests can develop under a variety of conditions within these climatic limits, and the kind of soil, plant, and animal life differs according to the extremes of environmental influences. Forests support a huge diversity of life, and despite their importance, they are being removed at frightening rates.
Forests are composed of about 60,000 known species of trees, making them some of the most complex ecosystems in the world. Apart from trees, the forest is also made up of soil, water, other plants, animals, birds, and insects. Many of these living things are dependent on other living things within the forest for their survival. Forests play a vital role in sustaining the life forms and atmosphere of our planet. They provide a habitat for all the living things contained within them. Forests are an integral part of nutrient cycles in our environment, ensuring that water, minerals, gases, and trace elements stored in vegetation and the soil are recycled to maintain soil fertility. Forests play an important role in gas exchange (e.g. carbon, nitrogen, and oxygen cycles) in our environment.
