1. What are the major reasons for the destruction of the rainforests and what people's lives their are hurt by this?
2. What can students, of all ages, do to help save the rainforest?
Rain forests are complex ecosystems that are essentially self-sufficient when
healthy. However, they are not easily regenerated once removed from
an area. A healthy rain forest will, for instance, thrive by
recycling most of the
nutrients needed for plant growth between living plants, animals and
decaying organic matter without outside intervention; however,
it needs a large variety of organisms to do this.
Once a parcel is deforested, it is unlikely that it will regrow to
resemble its past condition without massive human intervention
(which rarely occurs). In its place will likely grow a low-species-
diversity assemblage of organisms that will eventually deplete the landscape of
nutrients and therefore not be truly sustainable.
Thus, rainforest loss is typically permanent.
The global coverage by rain forests is dimished each year by human activities in order to support things such as agriculture, mineral resource exploitation, the hardwood lumber industry and urbanization.
There are a number of physical, biological and ascethic reasons to preserve rain forests. When not preserved, the effects on people can be both local and global in scope. A few are summarized below:
Rain forests exist in regions that are very wet. Both tropical and temperate climate examples can be found. A primary useful attribute of rain forests is that they control the rate of erosion in their watersheds. These forests disperse the energy of falling heavy rain and further reinforce the soil through their root system. Without such forests, fully-formed top soils would not be generated and instead, weathered and/or fresh rock would appear on the surface. Without soils, the large arrays of organisms that require it to live would not exist, nor would the fundamental chemical processes that occur in a healthy ecosystem take place. In addition, right after deforetation and possibly continuing for many decades hence, massive transport of soil and sediment particles occurs in waterways in the area, thus impacting aquatic ecosystems as well. Soil particles can contain high amounts of chemically-reactive substances and plant fertilizer ("nutrient") compounds; dispersing them into the environment in quick pulses can overwhelm an aqautic environment, causing such problems as "eutrophication" (the biological diminishment of dissolved oxygen below levels acceptable to most respiring organisms). Additionally, murky water allows less light to penetrate it (diminishing algal and other plant productivity), it traps heat and allows the waters to become much warmer than clear ones (affecting species makeup and the amount of biologically-important dissolved gasses it can hold), and affects the chemical composition of the waters (through adsorption and particle dissolution reactions).
Rain forests contribute to biologically-important gasses in the Earth's atmosphere: they produce a large percentage of the available O2 on the planet via photosynthesis (although the main source of oxygen on Earth is from phytoplankton in the oceans). When the forests are destroyed, the rate at which CO2 can be drawn from the atmosphere is diminished. CO2 is a "greenhouse" gas that helps regulate the temperature of our atmosphere. This gas is a biproduct of all respiring organisms, as well as a biproduct of the combustion of organic matter, such as fossil fuels. If CO2 builds up in the atmosphere, the average temperature on the surface of the Earth can increase, affecting most aspects of human life.
As rain forest is cleared, what grows in its place is typically opportunistic species such as grasses. These are not sufficient to keep the area from eroding or to allow the regeneration of a biologically- diverse ecosystem in the area. Because barren rock or soil reflects a great deal more incident sunlight than does a forested area, the local "heat" budget for a region can be drastically changed by deforestation, thus affecting the local climate.
Also, rain forests, particularly tropical ones, support a much greater number of species per unit area than other biomes on Earth. This species diversity is required for a healthy ecosystem. When we remove a large enough number of species from the species "web" of a complex ecosystem such as this, it can no longer fend off natural disasters such as disease or drought. Thus, even removing only part of a rain forest can cause the remaining forest to be non-sustainable or dramatically altered.
Additionally, many plants are known to produce chemicals ("natural products") with enormous potential for a large range of uses (controlling diseases, manufacturing, etc..). Because there is a large species diversity in tropical rain forests and because many are remote and largely uncharted, it stands to reason that as new species go extinct each day, we are loosing important chemical producing organisms we haven't even discovered yet. Often times, even after a plant has been found to produce a chemical that is useful to humans, we must continue to rely on the plant to produce it for our use because artificial systhesis of the same material is expensive or otherwise impractical.
A final reason to preserve rain forests is ascethic: These are truly beautiful regions of the planet, exploding with colors and aromas and exotic sounds. Although little lowland rain forest survives in Hawaii, most of our mountainous regions contain pristine or semi pristine rain forest. If you are ever in Hawaii or some other tropical locale, take a moment to head into the forest. You won't be disappointed
Dr. Ken Rubin, Assistant Professor
Department of Geology and Geophysics
University of Hawaii, Honolulu HI 96822