Background
The authors begin by noting that recently, according to the IPCC, "global climate has been warming as a result of increases of radiatively active gases (carbon dioxide, methane, etc.) in the atmosphere primarily caused by human activities," and that "human-induced climate change could lead to an increase in forest fire activity in Ontario, owing to the increased frequency and severity of drought years, increased climatic variability and incidence of extreme climatic events, and increased spring and fall temperatures," noting further that "climate change therefore could cause longer fire seasons (Wotton and Flannigan, 1993), with greater fire activity and greater incidence of extreme fire activity years (Colombo et al., 1998; Parker et al., 2000)."

What was done
In a study designed to see if any of these negative prognostications have come to pass, Girardin et al. reconstructed a history of area burned within the province of Ontario for the period AD 1781-1982 from 25 tree-ring width chronologies obtained from various sites throughout the province, spurred on, perhaps, by the increase in area burned within Ontario that is known to have occurred from 1970 through 1981 (Podur et al., 2002).

What was learned
The three Canadian researchers report that "while in recent decades area burned has increased, it remained below the level recorded prior to 1850 and particularly below levels recorded in the 1910s and 1920s," noting further that "the most recent increase in area burned in the province of Ontario was preceded by the period of lowest fire activity ever estimated for the past 200 years (1940s-1960s)."

What it means
Although the researchers say that, according to theory, "one should expect greater area burned in a changing climate," especially one that is driven by anthropogenic-induced increases in atmospheric CO2 concentrations, their findings supply no support for this contention. In fact, they argue strongly against it.

References
Colombo, S.J., Cherry, M.L., Graham, C., Greifenhagen, S., McAlpine, R.S., Papadopol, C.S., Parker, W.C., Scarr, T., Ter-Mikaelien, M.T. and Flannigan, M.D. 1998. The Impacts of Climate Change on Ontario's Forests. Forest Research Information Paper 143, Ontario Forest Research Institute, Ontario Ministry of Natural Resources, Sault Ste. Marie, Ontario, Canada.

Parker, W.C., Colombo, S.J., Cherry, M.L., Flannigan, M.D., Greifenhagen, S., McAlpine, R.S., Papadopol, C. and Scarr, T. 2000. Third millennium forestry: What climate change might mean to forests and forest management in Ontario. Forest Chronicles 76: 445-463.

Podur, J., Martell, D.L. and Knight, K. 2002. Statistical quality control analysis of forest fire activity in Canada. Canadian Journal of Forest Research 32: 195-205.

Wotton, B.M. and Flanigan, M.D. 1993. Length of the fire season in a changing climate. Forest Chronicles 69: 187-192.