Fire History
Did you know?
- The majority of trees in the boreal forest (the forest type occupying the Northern two thirds of the province), are intolerant to shade, (require full sunlight), and therefore cannot regenerate under their parents. Fire, in the absence of human intervention, is therefore necessary for their maintenance. (Using knowledge such as this, and incorporating information on property, structural, forestry, wildlife and recreational values in an area, and considering the past and forecast weather information and predicted fire behaviour; fire managers can in some cases help a forest by allowing it to burn.)
- In a large forest fire, different areas burn with different intensities, as a result of many variables and factors such as site; weather (lower relative humidity = drier fuels and greater intensity, higher winds = faster spread); and fuels (species, age and arrangement). This creates mosaics of severely, lightly burned and unburned areas within the overall burn perimeter and contributes to a wide diversity and patchwork of vegetation and species.
- The end result of fire for most animals is positive. Unburned areas continue to provide shelter, while burned areas (roots of many deciduous, herbaceous and grass plants are not killed) quickly produce new growth for food and cover.
- The cones of the jack pine require intense heat (over 70 degrees C) to melt a glue-like seal which allows for the release of seeds after the fire has passed. In a mature pine stand this results in the release of millions of seeds on each hectare of land. This not only provides food for birds and small mammals but starts up to 1/2 million new tree seedling per hectare as well.
- Scientists from around the world come to Ontario to study and monitor the effects of fire on different sites and the atmosphere, to both better understand its ecological and environmental relationships and to provide better planning tools for fire managers.
Facts About Fire
How many prescribed burns are there per year?
Resource managers plan for around 30 prescribed burns in Ontario each year. Of those 30, MNR participates in the delivery of 10-12 prescribed burns per year.
Name at least 3 reasons for prescribed burns?
The common reasons for these burn proposals are: the improvement of wildlife habitat, restoration and maintenance of oak savannah and tall grass prairie, to support recovery plans for species at risk, to test operational procedures and train staff, to prepare a site for regeneration, to control insects and disease.
What pieces of information are needed to plan an prescribed burn?
All prescribed burns require a plan. The detail within each plan is dependant upon the
complexity of the burn site and the environment that surrounds it.
Do fires burn quicker uphill or downhill?
Fires burn uphill faster and more intensively, than down.
How fast can a fire move?
A fast fire moves about 20 meters/min. This slow time frame allows small mammals time to find shelter in burrows, while larger mammals simply move out of the way or locate themselves in wet areas.
What causes lightning?
Lightning originates around 15,000 to 25,000 feet above sea level when raindrops are carried upward until some of them convert to ice. For reasons that are not widely agreed upon, a cloud-to-ground lightning flash originates in this mixed water and ice region. The charge then moves downward in 50-yard sections called step leaders. It keeps moving toward the ground in these steps and produces a channel along which charge is deposited. Eventually, it encounters something on the ground that is a good connection. The circuit is complete at that time, and the charge is lowered from cloud to ground. (Source: http://www.nssl.noaa.gov/edu/)
How far away from a storm can lightning strike?
It's not clear what the maximum possible distance might be. Lightning has been known to strike in clear sky areas that are more than 10 miles away from the area of the storm.
How long can a lightning bolt be?
Recent research from Vaisala-GAI's LDAR and LDAR II lightning detection networks show that lightning can travel 60 miles or more from the cloud to the ground. They find the longest bolts originate in the front of a squall line and travel 62 miles horizontally back into the trailing stratiform region behind the squall line. The longest bolt they have seen to date was 118 miles long in the Dallas-Ft. Worth, TX area. Since 3-D lightning measurements are relatively new, however, scientists are learning more every day and these numbers may change(Source:http://www.nssl.noaa.gov/edu/)
Three percent of all fires are greater than 200 ha, how much of total percent burned area is created by these large fires?
Fires greater than 200 ha represent 97% of area burned.(Source: http://www.nssl.noaa.gov/edu/)
How much heat comes off a fire?
An average surface fire on the forest floor might have flames reaching 1 metre in height and can reach temperatures of 800°C or more. Under extreme conditions a fire can give off 10,000 kilowatts or more per metre of fire front. This would mean flame heights of 50 metres or more and flame temperatures exceeding 1200°C. (Source:http://www.nssl.noaa.gov/edu/)
What are convections?
Convections are the Earth’s way of “evening out” heat and moisture across the globe, which occurs by the rising of air. Earth scientists are interested in detecting lightening because it pin points where and when strong convections will occur. It is important to detect lightning strikes to improve public safety during severe weather, warning managers of possible wildfire triggers, and protecting electrical and transportation systems. One helpful tool scientist use is yearly maps of lightening flashes, which help identify how the Earth’s climate, such as severe storms and precipitation, might be changing over time. (Source: http://fire.cfs.nrcan.gc.ca/facts_e.php )
