The Fire History of Old-Growth Forest in the Barro Colorado Nature Monument, Panama

Fire originates from human ignition in rainforests and causes major shifts in species composition. Given the long lifespans of tropical trees, disturbance and recovery processes occur over periods of centuries and are not fully captured in modern ecological surveys. We assessed the fire and vegetation history of the Gigante forest plot in the Barro Colorado Nature Monument using a series of 42 soil cores. We quantified macroscopic charcoal fragments in 10-cm depth intervals for the cores and obtained 14 C accelerator mass spectrometry dates on all 14 charcoal fragments of sufficient size. One charcoal fragment indicated that modern fire (ca. AD 1976) was found in the central regions of the plot. Eight of 14 fragments contained evidence of fires occurring between 900 and 600 years ago, and these cores were located in the central and southern regions of the plot. Our results are very similar to the ages of fire events and archaeological evidence found at Barro Colorado Island, which is 5 km away. These data indicate widespread and recurrent fire events across this part of the
landscape of Panama 900 to 600 years ago but almost no evidence of fire in the last few centuries.