Lightning strikes and resultant fires from archival (1912-1917) and current (1960-1997) information in Pennsylvania

Archival information was searched for evidence of lightning strikes and subsequent ignitions in Pennsylvania forests. Between 1912-1917, twenty-eight different tree species were struck by lightning 2553 times igniting 77 individual trees. These data probably underestimate the number of ignited fires due to rugged terrain, inefficient fire reporting, and minimal fire control resources of this early era. Lightning strikes occurred most often between June-August, peaking in July with 877 strikes. These data provide direct evidence that lightning strikes and tree ignitions occur relatively frequently in Pennsylvania forests. Recent data provide substantial evidence for large areas burned by lightning ignitions during drought years in the past thirty-seven years.