Expanding agricultural contributes to the rapid loss of forests and other habitats and their biodiversity. The tree removed can be used as timber or fuel or to manufacture paper. The removal of trees reduces the amount of photosynthesis which leaves more carbon dioxide in the atmosphere. Ever worse, the burning of fuel increases more greenhouse gases in the air. As a result, more and more carbon dioxide is trapped in the atmosphere, this adds problem to global warming.
Deforestation reduces the input in the nitrogen cycle. The soil loses fertility and is only able to support lower numbers and fewer species of plants. Harvesting takes away the nutrients from the soil, crops are harvested before they die and decompose in the soil. Farmers then add fertilizers in the soil to provide more nitrite ions for the crops to grow. However, the nitrite ions in the fertilizers are highly soluble and can easily leach into the rivers or seas. This causes eutrophication and leads to many death of organisms.
Human societies are concerned with global warming, deforestation, species extinction, the limits to long-term productivity and rising expectations. We understand the importance of healthy forests in our living planet. But the growing populations must be fed, clothed, and sheltered. Today, sustainability is a vital issue in forestry. When agricultural operations are sustainably managed, they can preserve and restore critical habitats and improve soil health and water quality. Conservation involves managing the Earth’s resources so as to restore and maintain a balance between the requirements of humans and those of other species. It is considered as a continual process of harvest and regeneration. Harvest of wood products as well as long-term productivity is the goal. Many attempts are being made to encourage sustainable use of forests e.g. , that is achieved by cutting the older, mature, and slow-growing timber to make way for a new crop of young, fast-growing trees. Scientists think of a lot of methods. There are three examples of harvest-regeneration methods which manage stands to produce timber on a sustained basis.
a) Selection - Individual trees or small groups of trees are harvested as they become mature. Numerous small openings in the forest are created in which saplings or new seedlings can grow. The resulting forest has a continuous forest canopy and trees of all ages. Such systems favor slow-growing species that are shade tolerant.
b) Clearcutting - In clearcutting, an entire stand of trees is removed in one operation. Regeneration may come from sprouts on stumps, from seedlings that survive the logging operation, or from seeds that germinate after the harvest. If natural regeneration is delayed longer than desired, the area is planted or seeded.
c) Shelterwood - In shelterwood systems, the forest canopy is removed over a period of years, usually in two cuttings. After the first harvest, natural regeneration begins. By the time the second harvest is made, enough young trees have grown to assure adequate regeneration. Shelterwood systems favor species that are intermediate in tolerance to shade.
In conclusion, conversation of forest is important and urgent. There is no easy solution as deforestation is caused by many factors. But for definite, decreasing the amount of use of products that are harvested from the rainforests and using recycling products help. The continuel deforestation wil only bring a severe consequence.
