Land ethic &sky islands

A big fire in 2002 destroyed large areas of forest on the upper slopes of Mount Lemmon. Looking at the results more than ten years later makes you think about how/if/why to help nature.

Mountains in places like southern Arizona are sometimes called “sky islands.” The forest systems on the mountains are different from the surrounding deserts. They are often remnant communities, left over from times thousands of years ago when the climate was much cooler. These island are fragile, both because of their limited extant, which makes it harder to regenerate from remnants, but even more because they are no longer really well adapted to the new climate conditions.

An established ecological community can create and maintain conditions that allow it to continue. That means that an established forest may be able to maintain itself, but would not regenerate on the same place if removed. This is the dilemma of restoration.

The idea that we should “let nature decide” is a little silly. We should seek sustainable systems, not strictly natural ones. When I looked out at the results of the fire I noticed the differences. Nature was not deciding; it was random chance. In some places forests had survived, maybe through a lucky change in wind direction. Here the sky island would remain. In other places the holes were too big. They would change. The forest biome would likely be replaced by a more scrub desert environment. Should we let that happen?

Human action could “restore” the forests to the conditions they had been in before the fire. This would not be the natural result, but it could be a sustainable one. It is more a value choice than a scientific one. Science delineates the boundaries of what CAN be done. We decide what should be done within that. I would advocate restoration.

A land ethic tells us that what improves the biotic community is a good thing. It dictates that we act responsibly and with caution. It implies an iterative process, doing, learning, changing doing better. But it does imply doing something beyond “letting nature decide.”