Numerous past environmental interventions have proved problematic, if not disastrous. For example, in 1890, the American Acclimatization Society, whose goal was to introduce nonnative species to North America, released about a hundred starlings in New York City’s Central Park. Rumor has it they wanted to bring every type of bird mentioned in the works of Shakespeare to the continent. An attempt in 1877 to introduce skylarks achieved moderate success, but starlings rapidly spread from coast to coast and today their descendants number upwards of 200 million in North America. Starlings are often considered pests: They displace native birds; they plague farmers by devouring crops; their droppings can serve as a vector for infectious diseases; and their swarming behavior can even pose hazards to jet aircraft.
Environmentalists often point to the starling, and similar ecological failures that have resulted from our attempts to introduce species, as exemplars of why we should not meddle with nature. To advocate for reducing activities that interfere with other forms of life, they say that “nature knows best.”
At the heart of this conviction is Leopold’s idea that we might have moral obligations to plants, animals and ecosystems. Leopold argued that “a thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise.” His land ethic often forms the basis for objections to industrial practices that would infringe upon sensitive ecological sites. Many modern environmental ethicists have further adapted from Leopold the idea that nonliving features of the environment also hold intrinsic worth themselves, even if they do not directly benefit humans.
On the other end of the spectrum is Locke, who wrote in his “Second Treatise on Government” that the resources of Earth are best allocated for human use. To Locke, the value of land was directly proportional to the value that humans could obtain from it. An unworked field was worth 10 to 100 times less than one being farmed in such a view, whereas the idea of a nature preserve might only be justified to the extent that it provides knowledge, happiness or other benefits to people. The legacy of Locke’s philosophy is seen in many policies today that seek to cultivate untapped resources for agriculture or industry. In many ways, the environmental ethics movement was a challenge to this mode of thinking.
In practice, the national parks system is a successful compromise that resulted from these two viewpoints. Modern forestry practices also show that a hybrid of the two views can provide enhanced ecological flourishing. On a large scale, managing hundreds or thousands of hectares of forest must, of necessity, take a broadly hands-off approach, as the large area of land would require an unrealistic labor force to tend effectively. But on the smaller scale of a forest stand, up to tens of hectares, human intervention can have direct and quantifiable influences on improving ecological health. The practice of silviculture provides guidelines for how we can effectively manage small-scale environments to achieve particular goals while maintaining the health of these environments.
Silviculture refers to the knowledge of growing forests, and the practices that emerge from silviculture are based on observations of tree and plant growth in a stand. Left on its own, a stand of trees may become overcrowded with saplings, which slows the growth of all plant life; but a little attention to tree spacing and canopy light allows a silviculturist to selectively cull a stand in order to maximize growth. Likewise, aggressive-growth plants may outcompete others and push stands toward monoculture, providing less support for local wildlife. Tending to factors like these can allow for effective management with only moderate knowledge of tree species and soil conditions.
Practicing silviculture requires a management goal — optimizing wood production, for example. Another example is “forest food” production, in which edible plants are integrated within a forest landscape, rather than creating separate garden beds. Still other examples include improving a forest stand for wildlife, preserving a stand for hunting, or preserving a forest simply for the aesthetic beauty that comes from ecological restoration.
Whatever the purpose, silviculture promotes the integration of human activities with our environment. Locke’s philosophy seems to artificially construct a separation between human and nonhuman activities; the same could be said of some applications of Leopold’s view. Rather than viewing humans and nature as competing entities, concepts like silviculture suggest that we can positively influence our environment through active, practical management.
Unfortunately, we cannot guarantee against future ecological catastrophes, and even in the seemingly mild approaches of silviculture there are risks of intervention. But we do have the ability to learn from past mistakes. Science and technology are not the enemies of environmental progress, but instead provide a means for learning how to effectively and sustainably manage our environment.