Fig. 3
From: Fire history and dendroecology of Catoctin Mountain, Maryland, USA, with newspaper corroboration
Graph of relationship of historical fires (1702 to 1951) to drought at Catoctin Mountain Park, Maryland, USA, created from data collected in our fire history study in 2018. (A) Welch two sample t-test was used to compare mean Palmer Drought Severity Index (PDSI) between fire years that scarred one tree and those that scarred two or more trees. The box represents the 75th and 25th percentile around the median PDSI, whereas the vertical whisker represents 1.5 times the interquartile range. Dots are data points that are outliers. (B) Superposed Epoch Analysis of PDSI across all fire years represented by two or more fire-scarred trees. Bars above the center line indicate wetter and cooler than average conditions, whereas bars below the center line indicate hotter and drier conditions than average. The floating lines above and below the mean represent the 95% (dashed) and 99% (solid) confidence levels. The numbers on the x-axis represent the time lag before (−) and after (+) a fire year (0)