Tree-Caused Electric Outages

Abstract

In 1995, Eastern Utilities was among 14 utilities in the United States and Canada participating in a study to collect and evaluate data about the phenomena of how trees cause outages. Results indicate that failure of trees accounted for 40% of the preventable tree-caused outages in the Brockton territory of Eastern Utilities. Even though line clearance tree trimming continues to be the primary strategy, programmatic changes were made in Eastern Utilities' Tree Management Program. A Danger Tree Project was initiated to identify and mitigate trees with structural weaknesses along the 3-phase portion of the electrical distribution circuits. Approximately 4% of the trees in the portion of the urban forest managed by Eastern Utilities will either be removed or stormproof pruned. Reliability has improved by 20% to 30% along the circuits where hazardous trees have been removed or storm-proof pruning has been done. Proactive communication within the community and participation in communitybased tree planting has accompanied this project.