ENVIRONMENT YUKON






 

Forests

Yukon wildland fires greater than 200 Hectares

 

Significance

 

 

Wildland fire is a natural and necessary phenomenon in Yukon. Under the right conditions, such as hot weather and low forest fuel moisture, Yukon's forests can support high-intensity wildland fires on the landscape. These fires often occur naturally and have the potential to spread quickly, covering large areas. The plant and wildlife communities of Yukon are well adapted to periodic wildland fire disturbances. For example, the life cycle of lodgepole pine forests, whose cones open up after exposed to significant heat from fire, usually starts and ends with a crown fire. Wildland fires help maintain healthy ecosystems and create forest mosaics that enhance biodiversity.

Fire management agencies across Canada monitor both the number of fires and the area impacted by wildland fires. Dramatic fluctuations in the area burned occur annually. Nationally, wildland fires greater than 200 hectares in final size represent a small percentage of the total yearly number of fire ignitions; however, fires greater than 200 hectares also account for most of the area burned and as such are an indicator of environmental change. Monitoring wildland fire trends in the Yukon is essential to understanding forest health and ensuring there are appropriate resources in place to protect human life and values at risk to fire.

The frequency and intensity of fires is expected to change with a changing climate (Wotton et al. 2010, Flannigan et al. 2009). Climate change factors, such as projected longer fire seasons, changes in precipitation and temperature , and additional stresses to forest and vegetation (e.g., drought, flooding, insects and disease) reinforce the importance of monitoring wildland fires.


Ensuring accurate baseline information is necessary to monitor environmental change. Monitoring trends in wildland fires also helps wildland fire management agencies to be prepared and have appropriate resources in place and ready to respond to wildland fires as necessary.

 

Campaign fire near Watson Lake.

 

 

What is happening?

 

Fires greater than 200 hectares in final size represent a small percentage of all fires, but account for most of the area burned (Figure 1).

 

Figure 1: Yukon number of fires greater than 200ha and area burned, 1975-2016

 

  • Since 1985, Yukon has had an average of 137 fire starts, which have burned an average of 171,840 ha every year. The total number of yearly ignitions and area burned varies significantly by year.
  • The 2004 forest fire season in Yukon saw unprecedented temperatures, unusual lightning storms and lack of rainfall over a prolonged period, which resulted in a record-breaking number of fires and area burned. Read a review of the 2004 wildland fire season.
  • In 2016, there were 53 fires that burned just over 20,000 ha. The fire season was marked by frequent and wide spread shower events that subdued fire danger. The 2016 fire season was less active than would be expected normally.

 

Figure 2: Yukon wildland fires greater than 200ha, 1946-2016

 

  • Figure 2 demonstrates that the vast majority of Yukon has been affected by fire since 1946. In fact, all conifer forests in Yukon are a result of a previous wildland fire.
  • Fire distribution across the landscape in any given year is dependent upon availability of forest fuels and appropriate burning conditions.

 

Taking action

 

To help balance the necessary role fire plays in maintaining healthly forests and reduce the unwanted negative consequences associated with wildland fires, Yukon has adopted FireSmart principles.

FireSmart provides a systematic approach for homeowners and communities to identify and reduce the risk of loss due to wildland fire. As we choose to extend our lifestyle and communities further into forested areas, we become more exposed to the danger of wildland fire.

For further information on FireSmart visit:

 

After a fire.

 

 

Data quality

 

There are two online data repositories for the area of wildland fires:

Yukon's Wildland Fire Management Branch collects data on reported fires during the fire season, which extends from April 1 to September 30, yearly. The data is compiled daily during the fire season and finalized by the following January.

 

  • The final fire perimeters are either collected by staff using GPSs or they are established using remote sensing technologies (i.e., satellite mapping). Capturing appropriate satellite images (e.g., cloud-free) of the area impacted by the wildland fire can take up to a year.
  • Minor gaps can occur as not all fires are detected and reported.
  • One limitation of using final fire perimeters for fire size is that it does not exclude islands of unburned vegetation residing within the final fire perimeter, nor bodies of water.
  • Using the 200 ha size threshold minimizes these data gaps, as fires greater than 200 ha occurring in remote wilderness areas are more likely to be detected. Fires smaller than this threshold do not significantly contribute to the total annual area burned.

 

References

 

Wotton, B.M., Nock, C.A. and Flannigan, M.D. 2010. Forest fire occurrence and climate change in Canada. International Journal of Wildland Fire 19:253-271.

Flannigan, M.D., B.J. Stocks, M.R. Turetsky, and B.M. Wotton. 2009. Impact of climate change on fire activity and fire management in the circumboreal forest. Global Change Biology 15: 549-560.

 

Fireweed often thrives after an area has burned.