PARENT SESSION
Symposium 1: The boreal forest and global change
Organized by: EA Johnson, K Miyanishi, and K Ruckstuhl
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 517 A, Level 5, Palais des congrès de Montréal

Human impacts in the boreal forest.

Granström, Anders ^*,1, Niklasson, Mats², ¹ Swedish University of Agricultural Sciences, Umeå, Sweden² Swedish University of Agricultural Sciences, Alnarp, Sweden

ABSTRACT- Throughout history, the boreal forest may have been one of the most sparsely populated biomes, but it would be a fallacy to equate this with fully natural ecosystems. Before industrial-scale timber extractions started, the major impacts should have been through overexploitation of key animal populations and through the use of fire. Fire is unique in that it is both a natural phenomenon and a cultural agent, and by looking at a variable such as fire frequency over time, it is inherently difficult to disentangle the effects of humans from that of climate change. Here we try to look at the potential impact of humans on boreal fire regimes, from a perspective of fuels, ignitions and culture. There are two primary ways for a low-tech culture to impact the fire regime: by altering the number of ignitions and their seasonal timing and by hindering the spread of fires. The potential for human impact should be greatest when natural ignitions are few, as appears to be the case throughout most of the boreal. Nevertheless, there is a negative feed-back due to fuel build-up that results in a diminishing effect on fire frequency as ignitions increase. Affecting the spread of fire may seem a less intuitive option, but could be effected by burning off fuels ahead of expanding fires, either as part of a fire management strategy or as a short-term tactic. Different cultures should be expected to have quite different attitudes toward fire. In Northern Scandinavia at least four such cultures can be tentatively identified. So far, there is evidence for the fire regime changes associated with three of those: a reindeer herding culture with few ignitions above the natural; an era of cattle husbandry and dramatically increased ignitions and somewhat higher fire frequency; and an industrial timber exploitation era with decreasing fire sizes and diminishing fire frequency. In other parts of the boreal, such schemes can look quite different, but we suggest that a close look at the resource extraction and land use in different cultures should be part of any analysis of past fire regimes.

Key words: Fire, Culture, Management, Boreal