A forest, also referred to as a wood or the woods , is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed. These plant communities cover approximately 9.4% of the Earths surface (or 30% of total land area), though they once covered much more (about 50% of total land area), in many different regions and function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the biosphere. Although forests are classified primarily by trees, the concept of a forest ecosystem includes additional species (such as smaller plants, fungi, bacteria, and animals) as well as physical and chemical processes such as energy flow and nutrient cycling.
A typical forest is composed of the overstory (canopy or upper tree layer) and the understory. The understory is further subdivided into the shrub layer, herb layer, and also the moss layer and soil microbes. In some complex forests, there is also a well-defined lower tree layer. Forests are central to all human life because they provide a diverse range of resources, they store carbon, aid in regulating our climate, purify water and mitigate natural hazards such as floods. Forests also contain roughly 90% of the world terrestrial biodiversity.
SOME FOREST PLANTS Forests are very important to us they serve as the green lungs of the world. Trees grow in forests. They are very important to NEEM us as they take in SHEESHAM carbon-dioxide released by us and give oxygen taken in by us. That is why forests are called green lungs of the world.eg: neem, semak,BAMBOO bamboo, sheesham. SEMAL
In biology, the canopy is the aboveground portion of a plant community or crop, formed by plant crowns. For forests, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms (epiphytes, lianas, arboreal animals, etc.). Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree or group of trees. Shade trees normally have a dense canopy that blocks light from lower growing plants.
UNDERSTORY Understory (or under storey) is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs. Young canopy trees often persist as suppressed juveniles for decades while they wait for an opening in the forest overstory which will enable their growth into the canopy. On the other hand, understory shrubs are able to complete their life cycle in the shade of the forest canopy. Also some small trees such as dogwood and holly rarely grow tall and are generally understory trees.
WHY SAVE FORESTS Forests are the lungs of the Earth! Not only do they purify the air we breathe, forests store carbon, help in maintaining global climate as well as recharge our water sources. Forests are therefore crucial for the survival of life on this earth! Forests are home to some of the most unique plant and animal species and support a diversity of life forms. The loss of forests has pushed many species to the brink of extinction. Forests are life support systems for the rural poor. Almost 90% of the earth’s poverty ridden communities depend on forests for food, fibre and energy. Forests provide free services to all life – water, soil and oxygen! About 30 million acres of forests are cleared globally every year! Almost 50% of the logging in forests is illegal. Deforestation causes 20% of all carbon pollution causing global climate change. Water sources are drying up and tons of soil is lost due to erosion. Flash floods and landslides are causing loss of life.
The water cycle, also known as the hydrologic cycle or H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapour, and solid at various places in the water cycle. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go, in and out of the atmosphere. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. In so doing, the water goes through different phases: liquid, solid, and gas.
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology.
The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be conveniently visualized as the surface of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as surface tension holds water in some pores below atmospheric pressure. Individual points on the water table are typically measured as the elevation that the water rises to in a well screened in the shallow groundwater.