The Impacts of Deforestation on Ecosystem of Pacific Northwest Rainforest
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The Impacts of Deforestation on Ecosystem of Pacific Northwest Rainforest
The Pacific Northwest rainforest borders Canada to the north and Pacific Ocean on the western side. Cascade Mountain Range divides it into two sections, and climatic conditions on each side of the mountain are different with the west side being wetter than the eastern side (Bigelow and Bob 9). The rainforest has experienced recent rises in temperature up to 4°F due to population pressure and deforestation.
Deforestation has become a major challenge over the world. It is the act of clearing forests to pave way for agricultural land, homesteads, or to obtain timber and firewood and is mainly attributed to high rate of urbanization and agricultural development in the world (Laurance and Carlos 92). Deforestation has marked effect on the ecosystem which comprises of both biotic factors like plants, animals and microbes and abiotic factors including air, water, soil minerals and energy in the form of sunlight which are interacting in harmony. Energy from the sun and atmospheric carbon gains entry into the ecosystem through photosynthesis and is later transferred to animals upon feeding with the photosynthetic plants (Braun 89). On the other hand, decomposers transform dead organic matter into a form that can be absorbed back by plants and microorganisms.
Disruption of this harmonious process occurs through deforestation. Humankind has resulted in intentional destruction of the rainforest for their benefits. The United Nations’ Food and Agriculture Organization (FAO) estimates that 7.3 million hectares of forest are destroyed each year while the global destruction of tropical forests stands at 50 percent (Bigelow and Bob 11). A case in point is the destruction of the Pacific Northwest Rainforest which is the largest rainforest on earth located at pacific coastline of North America and which comprises mostly of conifers, shrubs and bushes. The cutting down of trees in this tropical forest has resulted in several adverse effects on the ecosystem (Bigelow and Bob 19). Most important is the alteration of biodiversity, climatic change, soil erosion and depletion of water catchment areas in the region, and creation of agricultural land.
Deforestation causes massive soil erosion. In forest settings, the rate of soil erosion and runoff is minimal because land surface is covered with litter. Water penetration rate into the soil is approximately 15mm/hr. while soil erosion occurs at 0.1 mg/ha or lower. Disruption of the soil cover through deforestation increases soil erosion and surface runoff by several folds. The rate of water penetration drop to 5mm/hr. and rates of soil erosion increase to above 20mg/ha (Braun 149). Roads in the forest are characterized with even higher rates of soil erosion exceeding 100mg/ha.
Felling down of trees or fire in the forest reduces litter cover and compact soil layers causing an increase in runoff and soil erosion. Carrying away of fertile layer of soil leads to lose of nutrients and available soil water, hence, it causes reduction in productivity of the forest soil (Buongiorno 71). The Water Prediction Project (WEPP) model is used to predict the consequences of removing soil cover in terms of soil erosion, and it is known that nutrients lost by tree removal is more significant than lost in organic matter in sediments (Bigelow and Bob 49). The extent of soil erosion depends on the site-specific soil characteristics and the regions microclimate of the rainforest.
Trees act as a preventive measure for soil erosion by holding soil together through their roots. In addition, trees block the exposure of soil to direct sunlight, rain, and wind. Therefore, when these trees are cut down, the soil becomes loose and exposed to the agents of soil erosion (Perry, Ram, and Stephen 45). The soil nutrients are carried away by rain and wind and deposited in different areas, for example, seas and oceans where it is of little help. The volatile components like nitrogen volatilize on exposure to direct sunlight (Bigelow and Bob 42). Reforestation does not reverse the situation because the newly planted trees need time to develop an extensive root system, and by the time they grow, most of the essential nutrients will have been carried away from the soil, rendering the soil infertile and agriculturally unproductive (Braun 175). Consequently, the land becomes unsuitable for cultivation, which results in a decrease in crop production in the end.
The contributors to soil erosion are logging, fire, construction of roads, and harvesting of timber. Bare forests experience higher rates of soil erosion than those regions that are covered with vegetation (Buongiorno 113). Logging practice causes less soil erosion than construction of roads within the forest, but the effect is magnified by the fact that tree felling occupies larger track of land than the roads. However, deforestation results in decrease in evapotranspiration causing increased soil erosion by subsurface flow and channel erosion (Bigelow and Bob 11). On the other hand, compaction leads to soil erosion and, hence, deforestation causes soil erosion and diminishes soil nutrients.
The water cycle in the rainforest has also been altered. Water supply is essential for farming, energy production and ecosystem in the northwest region. Most of water in the northwest region is stored in the form of winter snowpack which melts and flows during summer and spring season (Braun 29). However, this situation is rapidly changing due to felling of trees in the forest causing an increase in winter temperatures which, in turn, causes snow to melt and exist in the form of rain. Consequently, drought can be expected during summer season while the run off become more unpredictable leading to increased risk of floods in winter (Bigelow and Bob 11). The decrease in water supply will not satisfy high water demand of agricultural irrigation, hydropower, and use in homesteads in the Pacific Northwest region. This is characterized by reduced electricity supply during summer, a sector that largely depends on hydroelectric power.
Plants absorb water from the soil using the root system, and this water is later lost through the leaves during transpiration process. Transpired water act to humidify ecosystem and this could account for up 50 percent of the moisture in the environment (Buongiorno 120). Therefore, cutting down of trees could lead to a drier environment since most of the water in the rainforest is stored in tree leaves. Therefore, deforestation has a marked effect on the water cycle. The alteration in water supply causes unexpected floods during winter and drought during summer with reduced hydroelectric supply (Bigelow and Bob 29). The economy, which majorly depended on electricity for production, is greatly affected while the floods cause financial losses to victims by carrying away their household items.
Loss of Biodiversity
Biodiversity has been lost from the rainforest due to natural and human activities. Biodiversity is the variety of life in the ecosystem and includes types and number of various species of plants, animals, and microorganisms (Braun 59). Extinction has been happening since time immemorial due to natural causes, but currently rapid increase in the rate of extinction due human activities has been witnessed. The tropical rainforest covers only a small portion of total dry land in North America (Schreurs, Miranda, Henrik, and Stacy 3). In spite of this, the forest hosts majority of plant and animal species, accounting for up to 80 percent of total plants and animal population (Bigelow and Bob 57). Massive destruction of this habitat leads to extinction of some species while some others reduce in number when they migrate to other forests.
Deforestation destroys biodiversity due to its destruction of the animal and plant habitats. Cutting of trees separates various sections of a forest causing discontinuity of the habitat, exposes organisms of deep forest to the peripheral effects of the rain forest, and disrupts plant reproduction process. Moreover, small germinating trees, which rely on the canopy trees for protection against direct sunlight are exposed causing them to dry out due to lack of moisture (Bigelow and Bob 76). In addition, animals that are dependent on trees for food, shelter, water and breeding site become extinct upon deforestation while the able ones migrate to other forests in the region. Plant pollination is also disrupted lowering the rate of plant reproduction and the few seeds that are dispersed land on harsh conditions and, as a result, do not germinate (Buongiorno 113)
Logging necessitates creation of new roads in the rainforests for the transportation of lumber (Dirzo 39). This causes soil erosion along the roads as well as exposes the interior of the rainforests to new environmental conditions, for example, increase in dust, temperatures and sunlight, and reduction in humidity. The new weather conditions cannot support vegetation that was adapted to the rainforest climate (Bigelow and Bob 27). The roads also act as entry points into the forest interior. People coming into the forest cause more deforestation along the conduits by grazing, hunting, and conversion of forest into farming land.
Auxiliary effects of deforestation, for example, pollution of the ecosystem, contribute to death and migration of animal and plant species from the rainforest (Perry, Ram, and Stephen 43). Silting of the nearby Pacific Ocean caused by logging and soil erosion leads to a decline in aquatic species, for example, fish and amphibians. Most of these species are highly valuable as human food and their extinction means that man has to seek alternative sources of food (Bigelow and Bob 39). The species are also important in the conservation of environment for beauty and tourism attraction.
The loss of biodiversity enumerated above take a lot of time and huge resources to reverse, if such attempts are made at all. These attempts include cultivation of the most endangered species of trees and rearing of rare animal species in restricted areas under special conditions (Braun 149). However, some of the extinct species can never be recovered; hence, there is the need to protect their natural habitats in Pacific North West rainforest by avoiding deforestation (Bigelow and Bob 76). Regulations set out by national and international bodies for preservation of biodiversity, for example, the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) need to be fully implemented. They help to curb the extinction of valuable species like the Pacific Coast mahogany (Swietenia macrophylla), Northern Spotted Owl, the Coho Salmon, Pacific Fisher, and the Mabled Murrelet (Laurance and Carlos 93).
Climatic conditions in the rainforest have changed. Global warming has become a major concern in the world and it occurs due to increased concentration of greenhouse gases such as carbon dioxide to toxic levels in the atmosphere (Dirzo 41). The excess carbon dioxide in air acts as a blanket trapping harmful radiations escaping from the earth. Radiations are then converted into heat energy causing global warming (Braun 58). Consequently, climatic changes occur leading to deserts and arid areas in previously productive areas.
The World Carfree Network (WNC) estimates that deforestation adds more carbon dioxide to the atmosphere than all cars and trucks in the world combined which account for up to 15% of global carbon emission compared to 14 percent due to motor vehicle emissions. Therefore, to curb global warming, efforts should be focused on reducing cutting of trees the same way people are focusing on increasing the efficiency of petroleum fuel and reduce of automobile use (Bigelow and Bob 98). Cutting of trees and the subsequent burning of trees in form of firewood or charcoal leads to emission of excessive carbon dioxide in the environment while those that decay generate carbon dioxide from stored carbon causing increased concentration of gas in the atmosphere.
Trees also act as the storage site for carbon in ecosystem by drawing greenhouse gas, carbon dioxide, from the air (Buongiorno 119). The gas is then used in the manufacture of metabolic blocks in plants, for example, carbohydrates, proteins and fats that are useful for plant growth and development. The reasons for rampant felling of trees in the forest are for economic benefits obtained upon selling the lumber, creation of arable farming land and pasture (Bigelow and Bob 27). However, the cost of conserving forests and benefits of avoiding deforestation outweighs economic benefits to the locals.
The pacific tropical countries should, therefore, be encouraged to participate in programs aimed at conserving the forest and receive incentives, for example, the United Nations’ Reducing Emissions from Deforestation and Forest Degradation (REDD) program (Bigelow and Bob 176). REDD gives direct financial incentives and educational support aimed at reducing deforestation in the member countries. This will reverse the effects of global warming over time.
Alteration of Coastal Resources
Coastal resources are greatly altered. The felling of trees in the Northwest rainforest causes alteration in climatic conditions which affect the coastal resources. The Northwest coastline experiences rise in sea level and landslides. This is due to climatic changes which lead to a rise in coastal erosion and loss of beach lines, especially in the Olympia, Tacoma, and Seattle regions which are highly populated (Braun 127). The sea level is expected to rise by 13 inches by 2100 and could cause an increased number of severe landslides mainly in highly populated and built up regions with unstable inclines.
The natural habitat for plants and animals is destroyed. The Pacific Northwest tropical forest is home for many animals and plants, for example, for the northern spotted owl. The organisms obtain food, shelter and breeding points in the forest (Bigelow and Bob 125). Deforestation destroys this habitat, and animals are forced to migrate to other regions in search of habitable environments, while others die because they cannot survive harsh conditions.
Reduced Agricultural Productivity
There is a reduction in agricultural productivity. Disforestation causes disruption of weather conditions in the Northwest, hence, climatic conditions become drier and unpredictable with global warming, massive soil erosion, and reduction in water for irrigation. This will negatively affect agricultural industry with reduction in crop and livestock production, hence, there is reduced income to farmers and the government (Bigelow and Bob 27). Food supply in the neighboring regions is reduced, increasing the cost of living since people have to buy food at a higher cost while they have little income.
Loss of Medicinal Plants
The supply of herbal medicine is adversely affected by deforestation. The northwest rainforest supports the growth of hardy trees adapted for wet winters and dry summers. However, the climate also allows growth of medicinal plant species which are used by herbal doctors to treat various human ailments. These plants include Usnea spp an antibiotic and anti-tubercular agent, oplopanax horridum an anti-arthritic agent, and Ganoderma lucidum an anti-hypertensive and immune suppressant agent (Bigelow and Bob 17). The depletion of these species affects health sector by reducing the options available to the community.
Soil Nutrients Depletion
Felling of trees affects soil nutrients. Cutting down of trees depletes nutrients in the soil, especially by removing nitrogen nutrients, a major contributor to soil fertility, from the soil. The extent of the depletion depends on the fertility level of the forest area. Leaching is also more marked in the infertile regions (Braun 110)
Logging indirectly causes an increase in transmission of diseases. This occurs for diseases that are spread by migrating animals, for example, Lyme disease, an inflammatory infection transmitted through a deer tick bite and malaria which is transmitted by female anopheles mosquitoes (Oosthoek and Barry 83). The diseases are more likely to originate from the parts of forest that are exposed to sunlight and are carried by animals which are forced to migrate in search for new habitats following deforestation.
Quality of Life
There is a reduced quality of life for neighboring communities due to silting, flooding and drought. The quality of drinking water is reduced due to presence of soil particles in water because of soil erosion, while floods cause destruction of properties and loss of lives and is attributed to the decrease in water retention capacity of the forest soil after logging (Buongiorno 162).
Deforestation also has some positive effects on human life. It creates additional farming and pasture land which can be utilized to increase agricultural productivity of neighboring communities. This improves food security for the region, improves standards of living and farmers’ income as well as earning government money in the form of taxes (Bigelow and Bob 129). The land can also be used to settle squatters and refugees from other countries.
Lumber and firewood obtained from the rainforest is sold to earn income. Thereafter, timber is used in the construction industry providing a cheaper alternative to stones and other construction materials, especially in the making of furniture (Oosthoek and Barry 81). In addition, timber-selling businesses form an important part of economies in the respective states.
Prescribed fire improves the quality of soil in the forest. A section of the forest may be subjected to fire intentionally, aimed at increasing the rate of decay of organic litter covering the soil by burning and improve soil structure (Braun 59). Consequently, more healthy plants sprout, and they are mainly comprised of medicinal plants like Usnea spp and better grass for pasture.
Deforestation in the Pacific Northwest Rainforest has caused a wide range of both negative and positive consequences. The undesirable effects which include climatic changes, loss of biodiversity, soil erosion, changes in water cycle, and spread of diseases outweigh the desirable effects such as creation of agricultural land and generation of income from sale of timber and firewood (Bigelow and Bob 199). The policies developed for the conservation of this endangered rainforest should be implemented through the relevant government and non-governmental bodies, and new trees and animals species should be introduced to recover destroyed sections of the forest (Schreurs, Miranda, Henrik, and Stacy 13).
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