Providing Lightning Protection

摘要

Arborists have been installing lightning protection since the 1800s. In 1933, J. B. Whitehead at Johns Hopkins University observed 61 protected trees around the university campus in Baltimore, Maryland. Many systems in historic trees around landmarkssuch as Mount Vernon, Monticello and the Hermitage have been in service for more than 50 years. In 2007, a veteran post oak (Quercus stellata) tree at Andersonville National Historic Site in Andersonville, Georgia, had to be removed due to irreversible lightning damage. Superintendent Fred Boyles does not want to lose any more. The region averages more than 10 lightning strikes per square mile annually, so the odds were good that another tree would get struck. He now has purchased enough material to protect at least 15 veteran trees from future lightning strikes.