(SitNews) - Few long-term fire histories have been reconstructed in coastal temperate rain forests, and little is known regarding the spatial and temporal characteristics of lightning and human ignitions.  However, a recent analyses of temperate rain forests by Southeast Alaska's neighbors on the central coast of British Columbia suggest that for centuries, humans have intentionally used fire to manage plant-life.

"Old growth temperate rain forests are often considered pristine and untouched landscapes, but new science is confirming what First Nations have known since time immemorial - that these forests were carefully managed with fire to increase the abundance of specific plants" said Kira Hoffman, lead author of the study.

Hoffman said, "These were slow-moving ground fires that left the majority of trees alive and kept the forest open and clear of brush, not the large, uncontrolled wild fires that we've become accustomed to today."

The researchers reconstructed 700 years of temporal and spatial aspects of fire activity with 30 plots on Hecate Island using fire scars and forest-stand establishment. They then conducted a paired study of 20 former indigenous habitation and control sites on 15 islands to relate fire activity to patterns of human settlement. The researchers mapped 15 years of lightning strike densities and use mixed-effects modelling to assess whether fire activity predicted the distribution and abundance of traditional plants.

Sixteen low- and mixed-severity fires were recorded from 1376 to 1893. The abundance of traditional plants and the density of western red cedar trees were best predicted by the location of former habitation sites and shorter mean fire intervals. According to the researchers, lightning is too rare to explain the pattern of fire activity in the study area. No fire activity was detected after 1893, coinciding with the relocation of indigenous groups from the study area.

The study found that fire was strongly associated with former indigenous habitation sites during the periods of occupation. People likely utilized fire as a tool for resource management to influence the densities of specific plants by creating mosaics of vegetation in different stages of succession.

By assessing the ecological impacts of historic fire events, a better understanding of the abrupt changes that occurred in the 20th century can be gained. The ability to understand present-day temperate rain forest ecosystems may be compromised if the role of humans in driving historic fire activity is underestimated.

The Journal of Biogeography recently published the study by Kira M. Hoffman /University of Victoria, Ken P. Lertzman /Simon Fraser University, and Brian M. Starzomski/University of Victoria.

The study was funded by Hakai Institute, the Natural Sciences and Engineering Research Council and the Canada Foundation for Innovation and the Ian McTaggart Cowan professorship at the University of Victoria.

On the Web:

Journal of Biogeography
Read the Full Study: Ecological legacies of anthropogenic burning in a British Columbia coastal temperate rain forest

Reporting & Editing by Mary Kauffman, SitNews

Source of News:

Journal of Biogeography
onlinelibrary.wiley.com

 

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