Climate and Indian effects on southern Ontario forests: a reply to Campbell and McAndrews

Clark and Royall (1994) questioned the interpretation, drawn from a simulation model, that climatic cooling was responsible for the demise of typical northern hardwoods taxa and replacement with taxa that require fire or soil disturbance, Pinus and Quercus. Those questions were raised because the model predictions did not well describe the data, the ecology of the taxa is not consistent with the interpretation, the other sites in the region do not show the patterns consistent with climate cooling, and stratigraphic charcoal data support an alternative interpretation. Campbell and McAndrews (1995) challenged our questions, but made no effort to answer them. Rather, they questioned an alternative interpretation that Iroquois maize agriculture contributed to these transitions. The main discus sion here is devoted to the uses of historic evidence, models, and sedimentary data to interpret climate vs. cultural effects. I review the evidence for fire that pertains to this region, and I reanalyze regional data to show that climate change does not provide an explanation for observed changes. I conclude with the observation that the inter pretation that climate alone is responsible for the transitions at Crawford Lake is still in need of explanation.

Duke Scholars

Author James S. Clark Environmental Sciences and Policy