Deforestation refers to the destruction of forest cover and tree stands for the purposes that are not related to forest regeneration, for instance, building, agriculture, grazing fields, destruction of trees, and abandoning the land. However, the term differs from ‘tree harvesting’, whereby trees are entirely removed from temperate areas (regeneration harvesting), where trees cannot regenerate naturally without natural or human disturbance (Oliver, 1980). Regeneration of harvesting has been praised by many scholars who argue that in cases of human interference in an environment, biodiversity regenerates in the same way as in cases of natural disturbance (Patel-Weynand, 2002). If destruction of forests is not accompanied by adequate reforestation, then desertification, loss of biodiversity, destruction of habitat, as well as increased concentration of carbon dioxide in the atmosphere are likely to be the consequences.
The United Nations Framework Convention on Climate Change attributes the increasing destruction of forests to agriculture whereby subsistence farming leads to deforestation at the rate of 48%, commercial farming at 32%, fire wood harvesting at 5%, and logging at 14% (UNFCC, 2007). Apart from agriculture, urbanization, road building, building of schools and other social amenities are also reasons why forests have been cleared to create space for developmental purposes. Deforestation has been used as a war tactic whereby forest cover is destroyed to deprive the enemies of hideouts as well as resources. Globally, deforestation is a thorny issue that has had many impacts including atmospheric, health, economic, and geological among others. Below is a discussion of the aftermaths of deforestation citing specific impacts in given geographical areas.
Atmospheric impacts have been brought by reduction of forest cover. Trees remove carbon from the atmosphere in the form of carbon dioxide, which is used in the process of photosynthesis as well as being stored in the plant cells and therefore, forests act as carbon sinks. This removal avails clean and quality air for breathing by both animals and human as well as ameliorating the accumulation of greenhouse gases. The unrelenting clearing of forests is exposing the globe to the increased greenhouse gas accumulation that results to global warming (Fearnside & Laurance, 2004). Cutting of trees reduces the rate, at which carbon dioxide is removed from the atmosphere, as well as it increases the release of gas into the air through burning and decomposition of wood. The increase in the level of carbon dioxide leads to the formation of a layer of gas that traps solar radiation and transforms it into heat that causes global warming leading to extreme environmental impacts, which include extremely hot weather and extremely heavy rainfalls during winter seasons. Reduction in forest cover in the Amazon region of Brazil has led to reduced rainfalls in the Manaus town as well as the neighborhood of forests since forests spread precipitation over a big radius (Mail Online, 2012).
Hydrological cycle is also greatly affected by deforestation. Trees hold soil firmly and reduce surface runoff by dropping leaves and old branches that slow speed of running water hence increasing absorption of it by the soil. The roots of trees suck water from soil and leaves release water into the atmosphere through evaporation hence increasing the amount of moisture in the air, which later turns into clouds to form precipitation. Deforestation leads to increased surface runoff while lowering the water infiltration hence leading to flash floods. Reduced water infiltration causes shortage in soil moisture that reduces the amount of water extracted from the soil and transpired into the atmosphere by trees hence lowering the levels of rainfall. In Malaysia, there are five states, namely Johor, Perak, Kelantan, Pahang, and Terengganu. All of them are said to have lost about 10% of their forest covers, when they were severely hit by floods in December 2014. The floods were to be blamed on the increased surface runoff that followed heavy rains (Butler, 2015). Flooding in cities is amplified by tarmac roads, paved footpaths, and car parks, which inhibit water infiltration as well as construction of buildings in the drainage ways hence obstructing the movement of water.
Deforestation also affects soil mechanics. Tree roots hold soil particles together hence stabilizing soil and reducing erosion by both wind and runoff water. Deforestation loosens soil and exposes it to strong winds hence making it vulnerable to erosion and landslides. Construction of roads and the use of machinery in forests also interfere with vegetative cover hence leading to soil erosion. The Loess Plateau in China that was well covered by forests has been cleared to cater for the increasing Chinese population and this has left the plateau exposed to agents of erosion that have left gullies behind. Erosion of soil from the air has led to sedimentation of the Yellow River as well as flooding. A layer of dusty soil covering Shanxi, Shaanxi, and Gansu provinces of China has also been caused by erosion of soil from the plateau. In Rondonia, Western Brazil, many immigrants populated the area, cleared forests, and started farming. After a few years, high rainfall levels and consequent soil erosion would leave the land infertile leading to clearing of more forest covers in search of good farming grounds (Lindsey, 2000).
Increased loss of biodiversity has also been caused by deforestation. Forests provide habitats for various animals and plant species whose specific niche is found deep in the forests. Deforestation therefore deprives such species of their habitat hence leading to their death or slow reproduction level, which leads to extinction of those species. The Rondonia state in Western Brazil used to have a forest cover of 200,000 square kilometers, 70,000 of which had been cleared by 2013 (Lindsey, 2000) as a result of influx of immigrants to the area. This greatly contributed to the loss of vegetation species as well as animals through migration, death as well as slow rate of reproduction hence alienating the land of its natural inhabitants including the microbial organisms that were found in the soil. Vegetation of the cleared area has transformed from leafy vegetation to grassland hence interfering with the natural biodiversity of the area.
Deforestation also leads to the economic decline. Decline in forest cover could lower standards of living by half for the poor group of people in the world and reduce the Gross Domestic Product by about 7% before 2050, according to biological reports (Black, 2008). Highly developed countries use wood for building and production of paper while in less developed countries many people depend on wood for fuel. The use and processing of forest products is therefore part of economic activities both in the developed countries and less developed countries. The short run economic benefits obtained from clearing of forests for farming as well as over exploitation of forest products subjects the global economy to reduced incomes in the long run. For instance, Madagascar and some countries of South Asia are earning lower revenues from forests due to reduction in forest cover (Butler, 2012). The atmospheric as well as hydrological effects of deforestation lead to low rainfalls in agricultural areas while effects on the soil lead to infertility of land causing reduced agricultural production that retards the global economy.
In conclusion, human activities are the greatest contributor to the problem of deforestation due to the need for space for settlement, agriculture, infrastructural development, building of town centers, and utilization of forest products among others. Population explosion has rapidly increased the need for space and therefore it is one of the reasons why human beings are overexploiting forests and their resources as well as clearing trees to settle in the forest lands. The harm that deforestation is bringing is more severe and unbearable and hence people must not continue living in indifference of the issue while exploiting forest resources blindly. The atmospheric effect, as a result of deforestation, is adversely changing climatic conditions through global warming, and if the trend is not controlled, it might lead to desertification of the whole globe.
Global warming is also leading to increased flood disasters due to abnormal precipitation as a result of accumulation of large volumes of water vapor in the atmosphere and also interference with the hydrological cycle. Reduction in tree cover has also facilitated soil erosion, sedimentation of rivers and mud flows as well as landslides that have claimed many lives and property as well as destroying the landscape. Deforestation has also led to reduction of biodiversity whereby different species of plants and animals are on the verge of extinction. Despite deforestation and over-utilization of forest resources, pumping of revenue into the global economy, the environmental costs, which outweigh monetary value, are too severe for both the current and future generations, hence there is a need to preserve forests and adopt green methods of fuel and construction materials.