Active layer depths: Boundary Fire Fireline (2004 - Present)

In 2004 the Boundary Fire burned an area within the Caribou Poker Creeks Research Watershed providing an opportunity to study various fire effects. When wildfire burns through a northern black spruce forest there is usually a subsequent increase in depth of thaw, due to the reduction in the depth of the organic layer. The construction of firelines with heavy machinery involves the complete removal of the organic layer and results in an even greater increase in active layer. This study was designed as a long-term comparison between depth of thaw on firelines, burned and unburned black spruce forest underlain by ice rich permafrost. This study will allow us to compare thaw depths from recent firelines to those studied at the Wickersham and Bonanza Creek fireline study sites. Within the fireline bulldozers were used to knock down and in some cases remove, the trees and organic layer. Within the safety zone an area approximately 30 m x 30 m was cleared to mineral soil. After the fire was out an excavator was used to return the organic material to the fireline and safety zones.