Wildfires in Canada

Grades 5 - 9

Wildfires have recently become an urgent concern in Canada. They significantly decrease air quality and pose threats to ecosystems, human lives, and the environment. This week, we explore the various causes of wildfires in Canada, identifying the most destructive types. Moreover, we explore why some classes of wildfires are more destructive than others, and propose possible explanations for the higher prevalence of wildfires during specific months of the year.

To answer our question we:

• Utilized datasets from the National Forestry Database (Forest Fires | National Forestry Database) from 1990-2021
• Identified primary causes by comparing hectares of land burnt with the number of wildfires
• Investigated trends in wildfire data, separating data by province and specific years/months

We defined five main causes of wildfires based on the National Forestry Database:

Human Activity: wildfires ignited by human actions, including accidental causes like discarded cigarettes, unattended campfires, sparks from faulty machinery, power line failures, or intentional acts of arson.

Lightning: wildfires ignited by natural electrical discharges. These fires are particularly prevalent in remote or forested areas where lightning strikes are more likely to occur.

Prescribed: wildfires intentionally ignited by fire management authorities for ecological purposes, such as promoting forest health, reducing fuel loads, managing vegetation, or restoring natural fire regimes.

Reburn: wildfires ignited by residual heat or smoldering embers from previous wildfires. Even after a fire has been extinguished, heat can remain trapped within logs, root systems, or organic matter. Under certain conditions, such as dry and windy weather, these residual heat sources can reignite, leading to new fires within previously burned areas.

Unspecified: wildfires ignited by unknown causes. Causes are unspecified either due to a lack of evidence or an incomplete data entry.

 

Visualizing the data

Using the dataset, we analyzed the leading causes of wildfires and the total land area affected by wildfires ignited by these causes (measured in hectares). Our visualizations indicated that human activity and lightning were the primary causes of wildfires and land destruction. As a result, our visualizations focus exclusively on these two categories.

These graphs illustrate that both human activity and lightning strikes have been the primary causes of wildfires over the years, with neither cause significantly outweighing the other. In specific years, like 1991, human activity caused more wildfires than lightning strikes, while in other years, such as 1998, lightning strikes surpassed human activity as the main cause of wildfires. However, wildfires sparked by lightning strikes seem to be significantly more destructive, scorching larger land areas than those caused by human activities.

Below are several factors contributing to the heightened destructiveness of wildfires caused by lightning.

Location: human-caused fires often occur in populated areas with well-managed vegetation, leading to smaller, localized fires. In contrast, lightning-caused fires can occur in remote and inaccessible areas, where it is easier for them to spread.

Natural Factors: lightning-caused fires tend to ignite in regions with favourable atmospheric conditions for fire spread, such as dry and windy weather.

Human Intervention: human-caused fires often begin in populated areas, prompting immediate responses that help mitigate their spread.

Some questions you might like to explore with these visualizations:

1. Are there any other factors that could explain why wildfires from human activity burn less land mass compared to lightning-based wildfires?
2. Do the visualizations provide any conclusive evidence on whether the number of wildfires is increasing or decreasing?