Canadian Forest Service Publications

Changing climate, vegetation, and fire disturbance in a sub-boreal pine-dominated forest, British Columbia, Canada. 2017. Brown, K.J.; Hebda, N.J.; Conder, N.; Golinksi, K.G.; Hawkes, B.; Schoups, G.; Hebda, R.J. Canadian Journal of Forest Research 47(5):615-627.

Year: 2017

Available from: Northern Forestry Centre

Catalog ID: 38933

Language: English

CFS Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1139/cjfr-2016-0283

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Abstract

Holocene climate, vegetation, and fire history were reconstructed using pollen, molluscs, and charcoal from two lake sediment records (Scum and Norma lakes) collected from the Chilcotin Plateau, British Columbia, Canada. In the late-glacial period, cold steppe prevailed and fire was limited. Artemisia steppe expanded in the earliest Holocene as climate warmed and conditions became dry, with shallow basins drying out. High-frequency surface fires maintained the steppe. An increase in Pinus after 10 200 cal BP signals moistening and the establishment of Pinus ponderosa P. & C. Lawson and Pinus contorta Dougl. ex Loud. stands, with surface fires in the former and higher severity fires in the latter. Cooling around 8500 cal BP favored P. contorta, and a crown fire regime likely prevailed, with intermittent surface fires. Shallow basins began to fill with water. In the mid-Holocene, basins filled further and Picea increased slightly in abundance. Fire frequency decreased, though severity increased. In the last three millennia, modern P. contorta dominated forests were established, with mixed-severity fire disturbance. Considering the future, the results of this study align well with ecosystem climate niche simulations, indicating that non-arboreal and openforest communities may again prevail widely on the plateau, together with surface fires. Land managers need to develop strategies to manage the upcoming transformation

Plain Language Summary

To understand how a certain type of fire disturbance might change in the future, it is important to understand how it has changed through time. The current research focuses on the records of the study of the ecology of fossils from two lakes on the pine-dominated Chilcotin Plateau, BC. The records were analysed for a variety of ecological, climate, and fire disturbance indicators. By examining how these indicators have changed through time, it is possible to evaluate how changes in climate and vegetation affect fire disturbance. The results show that climate has changed through time from cold and dry to warm and dry to cool and moist. Likewise the vegetation has changed from cold steppe to sagebrush prairie to pine forest. In response, the types of fires that occur in this region have also changed from what is known as a surface fire regime to a mixed-severity fire regime. The historic records of the ecology of fossils and results from our computer modeling indicate that the study region will change in the future as the climate warms, towards having fewer trees. In response, the modern mixed-severity fire regime may be replaced by what is known as a surface fire regime. Land managers now need to develop strategies to manage the upcoming changes.

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