Deforestation and biodiversity presentation essay

Chris Trucksess

While the loss of forests is clearly visible, a decline in biodiversity has a less apparent effect. The subtle loss of biodiversity fails to indicate the significance that fewer species in the ecosystem increases the fragility of life for all species. Despite the negative effects of deforestation and the consequential decline of biodiversity, trees are cut down for an economic and consumer benefit. Members of society need to determine how much economic cost they are willing to spend in order to preserve plant and animal species.

To reduce the degree of deforestation, tree harvesters may use selective logging, which involves only the removal of trees that are the most economically beneficial. Trees with lower economic value are left standing. This method still has problems intrinsic with any kind of deforestation and selective logging also introduces new environmental problems. Tree harvesters need to build roads into the forests to remove the timber (Vandermeer and Perfecto, 1995). The road construction means that a greater surface of land will be covered by asphalt, which increases the amount of rainwater runoff that is not filtered by the soil before entering a stream. These streams are polluted by sediment carried by the rainwater.

Vandermeer and Perfecto also say that selective logging introduces secondary damage when non-targeted trees are knocked down in the process of removing the desirable trees. In addition, selective logging over a long period of time leads to deterioration of the stand, which reduces the overall value of the forest when the loss of more valuable trees leaves lower grade timber behind (Vandermeer and Perfecto, 1995).

Another change related to the effect of selective logging is the changes that occur in the forest when a gap forms due to the loss of a tree. For tropical rainforests, the hole created by a fallen tree leads to changes that eventually affect the biodiversity of the habitat. The tree that previously occupied the space preserved a dark area of land within the forest. With the canopy of the tree to provide shade gone, light streams in and causes plants that do better in brighter conditions to force out low light plants that existed there previously. The loss of low light plants leads to a decline in biodiversity. Selective logging can bring about this change as well as the by the work of natural causes, such as storms (Vandermeer and Perfecto, 1995).

Deforestation can directly lead to biodiversity loss when animal species that live in the trees no longer have their habitat, cannot relocate, and therefore become extinct. Deforestation can lead certain tree species to permanently disappear, which affects biodiversity of plant species in an environment. The effect of deforestation can have the largest effect in tropical rainforests. According to the NASA Earth Observatory, half of all 5 to 80 million species live in the rainforests. Rainforests only make up seven percent of Earth’s total land area, making these habitats dense with life. Scientists have only named 1.5 million species in detail but yet about 137 species become extinct daily (Earth Observatory).

Treating biodiversity as important depends on accepting a model that has a counterargument unconcerned about biodiversity. The model that de-emphasizes biodiversity can be thought as a complex web of interconnections. The extinction of one species does not adversely harm other species or the ecosystem. Species that depended on the now extinct plant or animal can adapt and find other sources. This model opposes the biodiversity-dependent house of cards ideal. In this system, it is unclear what species are linchpins to ecosystem survival but when critical species become extinct, the entire ecosystem collapses. Other species cannot adapt when certain forms of life become extinct. The extinction of non-critical species has no ill effect but creates a false sense of security that any species can disappear without problem. However ecosystem failure is possible in this model when particular species die off. No one is sure which model best represents nature but it is safer to assume the house of cards model as correct. The consequence of this model is severe enough where it needs to be considered as a possible explanation until it is otherwise shown not to be accurate.

Puerto Rican Boa
Deforestation has made the Puerto Rican Boa an endangered species.

The size of households has an influence on the level of biodiversity and can serve as a method for maintaining the habitats of species. A reduction in the number of members of a household has lead to an increase in the number of households. This decline has been due to more divorces, an increased number of adults living alone after their children have moved out, and fewer extended families living in the same dwelling. The increase in households is possible even when the population declines. A study in Southeast Asia showed that more households tend to consume additional resources due to the increased consumption of wood for energy. The harvesting of wood through deforestation led to a smaller habitat for pandas (State Department, 2003).

Biodiversity is also related to global warming. Slow growth forests can take in a significant amount of carbon dioxide but deforestation immediately cuts the contribution to this important environmental function. When trees grow again on the deforested land, they are replaced by fast growth forests, which have a reduced ability to uptake carbon dioxide compared to the slow growth forests. The loss of the slow growth trees reduces the biodiversity and contributes to global warming (Vandermeer and Perfecto, 1995). Increased levels of carbon dioxide in the atmosphere trap more sunlight and raise the Earth’s temperature.

For solutions to the biodiversity problem, Sanchez-Azofeifa et al. studied deforestation near national parks. They concluded that national parks were a good starting point for conversation but they were not sufficient for species that need large habitat spaces in order to remain genetically stable (Sanchez-Azofeifa et al., 2002). From this finding the government could implement solutions to maintain biodiversity by establishing additional national parks. They could also tax companies that deforest and provide subsidies to companies that find alternatives to deforestation. Corporations could preserve biodiversity by finding sustainable methods for their use of resources. Biodiversity would benefit from individuals who choose to live in areas that have already been developed, reducing the need to clear additional forests.

Southwick’s solutions for deforestation, which would in turn help biodiversity, include awareness campaigns, forest conservation efforts, and social changes. For awareness, Southwick would like to see increased public recognition that deforestation is a problem, especially among business and government leaders. He supports the recycling of forest products, improved planting methods, and economic development that does not depend on deforestation. Southwick sees a need for jobs that are not based on logging in communities that depend on timber for their economy. Possible alternative jobs include environmental restoration. Southwick is in favor of selective logging, but as Vandermeer and Perfecto noted, this method can also be problematic. Finally, Southwick calls for a general social and economic restructuring that would reconsider the property rights of forests and the value of forests (Southwick, 1996).

Corcovado National Park map
The Corcovado National Park in the lower left of these map panels have much more forestland than surrounding unprotected areas.

These solutions do not completely address the problems associated with using the forests for timber. Society has a need and desire for forest-based products such as paper and wooden furniture. Companies and individuals need the wood from forests to provide economic prosperity and employment. With more restrictions on deforestation, the price of wood products may increase due to a reduction in timber supply. Plastic could be a viable alternative to wooden products but this synthetic material requires a supply of oil, which may be in demand for other uses.

Despite the benefit of national parks for preserving forests and in turn biodiversity, not all land can be protected in this manner. People need space to live, farm, and play, which means some deforestation must occur. Also, Vandermeer and Perfecto argue that fewer additional species are protected as more land is protected (Vandermeer and Perfecto, 1995). This conclusion suggests that a reasonable amount of protected land would preserve biodiversity while also leaving enough land to develop.

Preserving biodiversity is not without cost but the importance of maintaining a wide variety of species makes this endeavor a necessary problem to address. Action from the individual to the government level can help maintain biodiversity through increased awareness, less deforestation, and more protected land. Humans as a species are in threat of becoming extinct like any other species would if biodiversity continues to decline.

Graph of species versus preserved land
Saving 40 species requires 10 percent land protection, but saving twice that amount requires four times more protected land.


Earth Observatory. “Tropical Deforestation.” Retrieved April 16, 2003, from National Aeronautics and Space Administration <>.

Sanchez-Azofeifa, G., Rivard, B., Calvo, J., Moorthy, I. (2002). “Dynamics of Tropical Deforestation Around National Parks: Remote Sensing of Forest Change on the Osa Peninsula of Costa Rica.” Retrieved April 16, 2003, from BioOne <>.

Southwick, C. H. (1996). Global Ecology in Human Perspective. New York: Oxford University Press.

State Department. (2003). “Study Says Smaller Households threaten Worldwide Biodiversity,” January 15. Retrieved April 16, 2003, from United States Consulate Mumbai-India <>.

Vandermeer, J. and Perfecto, I. (1995). Breakfast of Biodiversity: The Truth about Rain Forest Destruction. Oakland, California: The Institute for Food and Development Policy.

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last updated 2003-05-17