Free Study Guide for Silent Spring by Rachel Carson - Book Summary
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CHAPTER SUMMARIES - SILENT SPRING
Other kinds of land is also under attack. There is more than 50 million acres of land under the control of utility corporations. These corporations routinely treat roadsides and access roads with herbicides to kill brush. In the Southwest, 75 million acres of mesquite trees are treated with herbicides. Timber producing land is also treated with herbicides. Agricultural land is treated with herbicides. Herbicides are used liberally in private lawns, parks, and golf courses. People treat herbicides as if they were harmless to the environment. The use of herbicides is cheaper in the short term than mowing, but in the long run, it is phenomenally more expensive.
People should realize the effect this destruction of the roadsides of the U.S. will have on tourism. In the summer of 1960 a group of conservationists got together in Maine to discuss the destruction of the earth by the use of herbicides. Everyone noticed the destruction of the landscape along the roadsides by government officials engaged in brush control. The same is happening in Connecticut where people have noticed the loss of roadside plants like azaleas, mountain laurel, blueberries, huckleberries and other beautiful plants. The wildflowers have also been killed off.
The practice of spraying herbicides on the roadsides is notorious for its abuses. People who are hired to spray roadsides will spray more than they were contracted to spray,
they will dump excess chemicals on the roadsides after doing a job, and they will kill plants that were not considered a problem. The designation of a wide variety of plants as "weeds" is wrong. They have been named weeds largely by the chemical companies that want to convince people of their deleterious effects. The chemical companies tend to scoff at the conservationistsí attachment to flowers and plants, not taking into account the fact that people have as much right to enjoy the flowers and bushes of the roadsides as the lumber company has to claim a tree.
There is more than just the aesthetic argument for preserving the plants of the roadsides. The shrubs along roadsides provide homes and food for wildlife. This vegetation is also the home of bees. People donít realize the importance of wild pollinators in growing food.
The use of herbicides on roadsides actually perpetuates the problem it is trying to solve. The use of herbicides has to be repeated year after year. There is a method of selective spraying that has been shown to work in the long term to control the growth of vegetation. The purpose of brush control is to get rid of plants that are so tall that they obstruct driversí vision or interfere with wires on rights of way. Most shrubs donít present a problem for either of these needs. Selective spraying would get rid of trees that obstruct the view and interfere with wires while leaving the good growth of brush in place.
The most common forms of herbicides are 2,4D, 2,4,5-T and other compounds that are related to these two. These herbicides are considered safe, but they have been known to cause severe neuritis and even paralysis in people using them. They also have been shown to damage chromosomes. Some birds have been adversely affected.
There are indirect effects of the use of herbicides. It has long been recognized that just after plants have been sprayed, animals are strangely attracted to the plants. Often plants that are not eaten by livestock and wildlife in normal life are eaten voraciously just after theyíve been sprayed. The chemical changes the plantís metabolism, making it produce more sugar. Another indirect effect is seen in the increase in nitrate content after a plant is treated. People have traced deaths in cattle to this indirect effect.
When people use weed killers, they usually donít think about the soil. They need to remember that soil and living things are interdependent. The weed is taking something from the soil and it is contributing something to it. In one example, the people who ran some of the parks in Holland noticed a problem with the growth of roses. They discovered nematodes in the soil were infesting the soil. Instead of using a herbicide, they planted marigolds because this plant releases something from its roots that kill nematodes. The roses quickly improved.
Plants that are wiped out by herbicides might be performing a function we donít yet know about. Weeds tend to indicate the condition of the soil. Learning about the indications of weeds would help people provide the proper treatment for their soil.
People who use herbicides need to realize the importance of preserving some natural plant communities. That way we can use these communities as a standard against which to test for changes in the environment wrought by human intervention.
There are warnings of gradual vegetation shifts that result from the use of herbicides. The chemical herbicide 2,4-D kills broad-leaved plants and allows grass to thrive in reduced competition. Now some of these grasses have gotten out of hand. Ragweed is one of the most bombarded of the weeds along roadsides. People donít stop spraying it even when they realize that ragweed tends to grow back more after a herbicide attack. Since herbicides kill shrubs, they leave open space for ragweed to thrive and spread. Another common target is crabgrass. Yet it has long been known that crabgrass only thrives in poor soil. Improving the soil will get rid of the crabgrass.
Home gardeners have been taking the advice of nurserymen who are themselves led by chemical manufacturers of herbicides. They have no idea that many of the herbicides they use contain dangerous chemicals like mercury, arsenic, and chlordane. The recommended portions of mixture for treating a lawn or garden are often outrageously high.
There are alternatives to the widespread use of herbicides. Selective spraying, mentioned above, creates long term solutions. Biological control is another successful way to control vegetation. One example is the case of the Klamath weed in California. It was brought over from Europe, where itís called St. Johnís Wort, and when it hit California it spread unchecked because none of its natural enemies had been imported with it. In Europe the natural enemies of St. Johnís Wort are two kinds of beetles. These beetles were imported to the United States and they succeeded in controlling the weed beyond what anyone had hoped for. Another example is set in Australia where one sea captain brought cactus over. It spread and, like St. Johnís Wort, grew rampantly, making huge amounts of land useless. The Australian entomologists studied the insect enemies of the cactus in North and South America. They brought back the eggs of an Argentine moth. Seven years later, the cactus was gone. These solutions have been cheap and effective.
If only people would look to these examples, the problem of herbicides could be eradicated.
Chapter 6 continues the plan of the book to describe the total environment and what insecticides do to each of its components. Here, the author describes the plants of the earth. It is a chapter that describes a world much more familiar to most readers than the subjects of the previous chapters. Whereas most of us know little of microscopic organisms of the earth or the structure of chemicals in the world, most of us live our lives thinking of trees and shrubs as our familiars, the furniture of the world outside our homes. Because of their familiarity, Carsonís persuasive technique in this chapter is to appeal to our affection for the beauty of the plants and flowers of our world. She invokes a protective impulse in her readers when she describes the pretty plants and trees being destroyed with irrational and ineffective methods which not only destroy the landscape but also contaminate the world further.
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