A solution to the tragedy of the commons?

Almost 40 years ago Garret Hardin described the tragedy of the commons. "Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons." The problem, of course, is that if all of us share a common pasture, then it always makes sense for me to add more cattle, even if doing so degrades the pasture, because I'll still get more out of the pasture than if I didn't add cattle. And I'm worse off when I don't add cattle, because you probably will, and the cattle I have left won't do as well. Even if you and I and all of our friends agree to limit our grazing, if there's one person who decides to cheat, that person will benefit and the rest of us will suffer.

That's the tragedy, and the good news is that there may be a way out.

Ashwini Chhatre and Arun Agrawal describe research on governance of forest commons suggesting that when local people, those who share the forest resource in common, enforce regulations on its use forest regeneration is more likely. What makes this study striking is that Chhatre and Agrawal also examine the role of other factors in determining the probability of forest regeneration: size of the forest, extent to which local residents depend on the forest for subsistence, commercial value, and collective action. Moreover, their data set also includes a wide diversity of forests, some in wealthy countries like the United States, others in lesser developed countries like Bolivia and Tanzania; some as small as 5ha, others of more than 5000ha.

Not surprisingly, Chhatre and Agrawal find that the impact of each factor depends on context. As Thomas Dietz and Adam Douglas Henry put it in an accompanying commentary,

[T]hey find that the commercial value of a forest increases the chances of regeneration when there is strong local enforcement of rules, but commercial value decreases the chances of regener ation in the absence of local rule enforcement. It follows, as they note, that enforcement matters, as do markets. How each factor matters depends on the other factors.

So there isn't a single solution. There are many, and with careful attention to local context solutions are possible.