Gary Becker, the Economic Approach to Crime, and Guerilla Grafters

Josh Wright —  8 April 2012

Fruit trees in a number of cities, including San Francisco, are prevented from bearing fruit in the name of “protecting” pedestrians from slip and falls and keeping away insects and vermin.  In response to these regulations, a group of Guerilla Grafters has emerged to — you guessed it — graft fruit bearing branches onto the non-fruit bearing city trees.

But grafting trees to bear the occasional pear is not all fun and games, apparently.  San Francisco officials consider the renegade arborists to be engaged in a serious offense (San Francisco Examiner):

While the grafters’ activities might seem harmless, Public Works Director Mohammed Nuru said the renegade gardeners are running afoul of the law.

“The trees that are in the right of way, they’re not for grafting,” he said. “The City considers such vandalism a serious offense. There would be fines for damage to city property.”

Nuru had not heard of Guerrilla Grafters, but said he would ask his staff to investigate. Meanwhile, he added, if the grafters have ideas about urban agriculture, they should discuss them with city officials.

NPR embeds one reporter with grafter Tara Hui on a covert grafting operation.  The first thought that crossed my mind as I read the story was skepticism that the costs associated with fallen fruit on city trees could be significant.  The second was hope the story had overestimated the prevalence of this type of regulation.  There is also some interesting law and economics.  The cops and robbers angle in the NPR story with Hui attempting to avoid detection for fear of sanction by the city authorities in the way of fines for vandalism was also interesting.  From the standard Beckerian model of rational criminal behavior we see Hui’s sensitivity to changes in the “price” of engaging in guerilla grafting (that is, the probability of detection weighted by the sanction she will pay if caught) and investments to avoid detection.

But what about the economic benefits?  Here’s Hui’s account:

“If we say where it is, they could come after me,” says Tara Hui, a fruit tree grafter. She’s talking about city officials, who manage the trees and say it’s illegal to have fruit trees on sidewalks.  So let’s just say we’re in some Bay Area city in a working-class neighborhood, at a line of pear trees that bear no pears.

Hui and two assistants pull out a knife, reach into a plastic bag filled with twigs no bigger than your pinkie, and cut from a fruit bearing pear tree. She says it’s an Asian pear, and that she’s grafting it onto a flowering pear tree.  They whittle a wedge into one end of their twig, then cut a groove into a similar-sized twig on the city tree. They join the two, like tongue and groove carpenters. And when their grafted twig eventually grows into a branch.

“There will be a much better looking tree that actually will provide fruit for people that come by,” Hui says.

Hui’s motives to break the law are straightforward.

“We don’t have a supermarket and we have very few produce stores [here],” she says. “What better to alleviate scarcity of healthy produce in an impoverished area than to grow them yourself and to have it available for free.”

For a recent and illuminating paper on the law and economics of criminal behavior which attempts to incorporate conventional critiques of the economic approach — for example, that criminals lack self-control, have non-standard preferences or do not act in their own self-interest — into the standard model, see Murat Mungan’s Law and Economics of Fluctuating Criminal Tendencies.  Mungan’s main goal is to show that the standard economic approach is capable of modification so as to absorb more realistic assumptions and that it gains explanatory power by doing so.

HT goes to Steve Salop for pointing me to the Guerilla Grafter story.

3 responses to Gary Becker, the Economic Approach to Crime, and Guerilla Grafters

  1. 

    It may be nice in theory, but they’ve failed to consider another economic problem, which is the tragedy of the commons. Not only will the fruit tree be uncared for, but the fruit will likely be picked well before its ripeness by someone who realizes they cannot leave the fruit to continue ripening lest someone else take it first.