Forest health monitoring protocol applied to roadside trees in Maryland

Abstract

The Maryland Roadside Tree Law places trees in all public road rights-of-way in the State of Maryland, U.S., under the jurisdiction of the Maryland Department of Natural Resources-Forest Service. Passed in 1914, this law is one of the oldest tree conservation laws in the United States. However, little statistical data have ever been generated related to Maryland's roadside trees. This paper provides a methodology for assessing the condition of roadside trees by combining GIS tools, rights-of-way definitions, and components of a national forest health monitoring program. The assessment of roadside trees was carried out in six of Maryland's most urbanized jurisdictions. Results indicate that 14% of Maryland's roadsides are tree lined and that the trees are in good health based on crown and damage indicators collected. Shannon-Weaver index and importance values were calculated to describe species diversity. Views on the efficacy of the law in protecting roadside trees in light of the findings, and the findings themselves, are discussed.