Silent Spring: Chapter 6 Summary & Analysis

Man cannot exist without plants, but we have a narrow view of their usefulness and are quick to label them as undesirable – and attempt to eradicate them – if they serve no immediate, obvious purpose. However, each plant is part of a complex web of life, and the essential relationships between actors in that web should not be disturbed without careful thought. Unfortunately this is not the normal procedure with modern spraying practices.

The attempted eradication of the sagebrush from the West is a perfect case study. The sage is a result of long ages of experimentation by nature, and is perfectly adapted to its unique, harsh environment at the edge of the Rocky Mountains. It lives in concert with other creatures in its environment, like the sage grouse, a bird that, during mating season, loosens the soil beneath and around the sage so that grass can grow.

When farmers decided to clear away the sage with pesticides to create more grazing land, the other organisms that had grown up alongside it, including the sage grouse, the pronghorn antelope, and sheep, for which sagebrush was an important grazing material in its own right, immediately suffered. The grass that the sage had sheltered also disappeared, crippling the farmers’ plans. Further, without sage there was nothing for livestock and wild grazers to eat during the harsh winters.

Another case comes from Supreme Court Justice and environmental writer William O. Douglas, who tells the tale of herbicide sprayings in Bridger National Forest in order to try to eliminate the sage. Untargeted spraying for sage also killed the willows, which had been home to the rare and wonderful moose, and disrupted beaver communities. Without the beaver dams, a beautiful trout lake at the end of the stream drained away, and this natural jewel and popular destination was lost.

Carson argues that weed-killers are tempting toys that appeal to those who want the spectacular illusion of power over nature and can believe in a ‘cheap’ alternative to mowing without considering true costs. One of these costs is in tourist goodwill, after beautiful roadside vegetation has been destroyed by the indiscriminate spraying of intolerant or careless weed sprayers, who view any brush at all as undesirable. In Maine, Connecticut, and Massachusetts there has been public outcry after spraying devastated natural undergrowth.

Carson describes with feeling one stretch of road she knows personally that which has been sprayed, with the exception of a few oases that now serve as painful reminders of the beauty that existed before. Why, she asks, must we consider all of this beauty to be ‘weeds’? She recounts another passage from the writings of Justice Douglas on sage lands, who eloquently defends the right of an old lady to question those who planned to destroy the sagebrush because their spraying would also destroy local wildflowers. We have a right, argue Douglas and Carson, to the aesthetic pleasure of natural beauty.

Beyond aesthetic considerations, there are practical reasons not to destroy so-called weeds. They provide the habitat for pollinating bees and other essential insect life, as well as animal life. Blanket spraying, in which whole areas are covered with a shower of untargeted pesticides often must be repeated when weeds return. Other methods, like smarter, selective spraying that only attacks unwanted, tall weeds, make use of the natural ability of persistent shrub cover to ward off the growth of taller weeds, and are therefore more effective and less disruptive. If taxpayers understood the inefficiency and danger of blanket spraying they would demand a change.

Herbicides like 2,4-D also have negative effects on livestock and wildlife that are not well understood. The herbicides accumulate in the soil, and can change a plant’s metabolism so that it produces more sugar and becomes more attractive to livestock – who can then be adversely affected (or killed) by eating the infected plant, which they might normally avoid.

Moreover, the positive effects that certain ‘weeds’ have on the soil are underappreciated – we must remember that soil processes exist within a system in which many players participate. In Holland, marigolds that were planted among dying roses helped to control the spread of harmful nematode worms, a solution that has now been replicated elsewhere. By spraying without considering the many interdependencies at work in ecosystems, humans are changing the nature of wild habitats in unknown and long-lasting ways.

As proof that blanket spraying is ineffective, Carson considers the case of ragweed. Spraying ragweed does kill it, but the plant is an annual, which means that seeds sprout anew every year. And the new sprouts need clear soil in order to thrive. While blanket spraying kills the ragweed, it also kills everything else, providing exactly the open soil that ragweed requires to grow the next year, which then requires more spraying, etc. A better strategy for controlling ragweed would be to plant stable perennial vegetation, whose year-round presence would limit any open soil and serve to restrict the new growth of ragweed each year while also reinvigorating wild habitats.

Other intelligent, cheap, natural strategies for ‘weed’ control exist, including the importation of natural predators to control invasive species. Klamath weed, an incredibly fast-spreading invasive species in the American West, was controlled by an imported beetle. In a similar fashion, rampant populations of imported prickly pear in Australia were reigned in by an Argentine moth. These alternatives are far preferable, argues Carson, to the destruction caused by herbicides.