Fire recurrence in the subarctic and its implications for vegetation composition

The Weibull distribution is shown to fit well with empirical data of fire intervals for a population of sites. The distribution demonstrates that the recurrence of fire in the subarctic forests of the Northwest Territories, Canada, is predictable. The three parameters of the distribution describe in ecological terms the lag before reburning can occur, the expected recurrence time of fire, and the shape of the variation around the expected recurrence. The parameters behave consistently with logically independent empirical evidence related to the regional and local climate and topography. The relationship of the distribution's hazard of burning function to vegetation composition and r–K selection is discussed.