Best practices for managing hazardous trees
Invasive Species/Vegetation Management
Under 1 year
Roadside trees can create hazards in different ways beyond the crash risk with a fixed object. Additional hazards that create transportation risk are dropping limbs or entire trees falling into the roadway. Trees as fixed objects are addressed in Volume 3 of NCHRP Report 500: A Guide for Addressing Collisions with Trees in Hazardous Locations. However, this report does not address the hazards of trees with defects that are not fixed objects. This proposal is required to fill this gap. In this project, a researcher will survey State and local transportation agencies and utilities, vegetation management contractors, electric utilities, the United States Forest Service and state forestry agencies for existing policy, guidance and practices in identifying and removing hazardous trees. From these surveys, the researcher will compile a list of recommended best practices for transportation agencies to consider when developing or updating policy guidance and practices for hazardous tree management programs on rights of way. The intent is to create or support programs managed by people who are trained in managing hazardous trees, not create new programs dependent on credentialed, certified arborists. It will also provide useful information to support DOTs in discussions with resistant land managers regarding the need to manage trees that are hazardous from a transportation perspective. Issues to be addressed include: • Transformational Technologies: Anecdotal reports suggest some jurisdictions are using LIDAR remote sensing technology, Forward Looking Infrared (FLIR) systems and aerial drone surveys to evaluate tree health. This synthesis could surface actual uses of LIDAR and FLIR for others to consider. • Resilience: During storm recovery, one of the most important transportation tasks is to clear fallen trees and limbs. Many of these trees and limbs fall because of undetected defects. This study could help jurisdictions strengthen tree condition monitoring to improve post storm recovery. • Public Health: Better management of hazardous trees protects the health and safety of transportation systems users and workers.
Transportation agencies have varying guidance and approaches to identifying hazardous trees and then removing them in a safe and productive manner. Discrepancies in definitions of hazard trees can create delays in addressing the risk and conflict with adjacent land managers. This project would assist DOTs with developing a useful definition of 'hazard tree' and provide information on a range of methods being used to manage them.
New York State DOT
February 8, 2017
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