There's little debate that, when a tree falls near a city street, it makes a sound. But other questions are more difficult to answer: Who is affected by the falling tree and how? Who is liable for the damage? And who is responsible for deciding how to replace the tree?
A paper written by an Indiana University professor and doctoral student, and presented at two international conferences, argues that thinking of street trees as a "common-pool resource" can help lead to better management of an under-appreciated community asset.
"We hope it will impact how cities look at their trees," said Burney Fischer, clinical professor in the School of Public and Environmental Affairs at IU Bloomington and co-author of the paper with Brian Steed, a doctoral student in SPEA and political science. "Obviously, a lot of cities haven't yet stepped back and said, 'Why do we do this the way we do it?'"
The paper, titled "Street Trees -- A Misunderstood Common-Pool Resource," was presented this summer at meetings of the International Association for the Study of the Commons in Cheltenham, England, and the International Society of Arboriculture in St. Louis.
In Cheltenham, Fischer also presented the paper in a pre-conference session on "new commons." New commons are various types of shared resources that have recently evolved or been recognized as commons. They are commons without existing rules or clear institutional arrangement to govern their use or protection. Resource sectors identified in this widely expanding area include scientific knowledge, voluntary associations, climate change, community gardens, wikipedias, cultural treasures, plant seeds and the electronic spectrum.
Fischer and Steed argue that street trees fit the definition of a common-pool resource because they benefit many people but their use (or abuse) is difficult to control. The authors draw on a body of academic writing about common-pool resources, starting with Garrett Hardin's essay "The Tragedy of the Commons" (1968) and including the widely cited Governing the Commons: The Evolution of Institutions for Collective Action (1990), by Indiana University political scientist Elinor Ostrom.
Ostrom is founder and co-director of the Workshop in Political Theory and Policy Analysis at IU, where an initial version of the Fischer-Steed paper was presented late last year.
Loosely defined as trees that line municipal streets, street trees produce a myriad of benefits. They provide shade, filter air pollution, absorb greenhouse gases, reduce storm water runoff, slow traffic, improve property values and contribute to aesthetic beauty. But if not properly maintained, they can become traffic hazards; and they can drop limbs, causing property damage and even injuries.
Yet street trees (and urban forestry in general) haven't been made a high priority by many cities and towns, Fischer said. While initiatives are under way to plant hundreds of thousands of trees in some cities, the paper points out that tree cover has declined dramatically in Chicago, Philadelphia, Washington, D.C. and other urban areas.
And street trees are subject to a patchwork of management schemes, developed under a wide variety of state and local laws. In some cities, local government is responsible for street trees. In other locales, it is up to private property owners to plant and care for street trees. Elsewhere, civic groups and neighborhood and homeowner organizations take the lead in managing street trees, which includes not only planting and pruning trees but deciding which species to plant and where.
The end result is that, for many communities, the citizens really do not know which trees are 'street trees,' who is responsible for them or what the 'rules' are regarding their management and protection.
Fischer said there are pros and cons to each approach, and more research is needed to better understand how communities are managing street trees and which methods are effective.
"We need to look at ordinances across multiple states and see if there are common features. We haven't done that," he said.
One basic problem, the paper points out, is a lack of monitoring of the street-tree resource, even at the level of having an inventory of the number, placement and condition of street trees in a community. In Bloomington, Fischer and three students authored the 2007 Bloomington Street Tree Report: An Analysis of Demographics and Ecosystem Services as an outgrowth of a SPEA urban forestry course. It was the first update of the city's street tree inventory in 13 years.
"Inventory is critical," Fischer said. "Without a current inventory, you can't write a street tree management plan."
Source: Indiana University
Explore further: When it comes to how pizza looks, cheese matters