Entry Quiz

Introduction

Learning outcomes:

To be able to:

To describe the nature of wildfires
To understand the conditions favouring intense wild fires
To evaluate the importance of natural and human causes of wildfires in different places

Specification content: Nature of wildfires. Conditions favouring intense wild fires: vegetation type, fuel characteristics, climate and recent weather and fire behaviour. Causes of fires: natural and human agency.

Where are we on our specification?

Key words:

Starter

Which are causes of wildfires?

Look at one of the images from https://slaveevo.com/goto/?ai=3189. What can you learn about wildfires from your chosen image?

Wildfires are often seen as destructive, but can be a natural process in many ecosystems. Fires can cause widespread destruction and kill wildlife. Surface fires burn leaf litter and grasses as they sweep over the ground and scorch trees; temperatures can rise to 1000⁰C. Crown fires can spread through the canopy of trees.

Nature of a wildfire

The nature of a wildfire will depend upon factors such as:

Types of plants
Strength of winds
Topography of area
Behaviour of the fire

Nature of a wildfire

The largest fires happen when there is dry, windy weather with low humidity. Wind drives the fire on and spreads embers which ignite more vegetation.

Nature of a wildfire

Natural fires require an ignition source and fuel. Lightning is by far the most likely ignition source and the likelihood of this is dependent on the climate of the area. There has to be enough fuel and it needs to be dry enough to burn. Again, climate will influence frequency and duration of droughts.

Nature of a wildfire

Increasingly, fires are caused by human activities such as falling power lines, dropped cigarettes or camp/agricultural fires which get out of hand. Some fires have been started deliberately.

Where mainly do wildfires occur - in rural or in settled areas? Why?
Which places of the Earth - areas with dry vegetation and lightning strikes or wet vegetation are most susceptible?

Nature of a wildfire

Wildfires mainly occur in rural areas, but with people inhabiting more areas wildfires can occur in settled areas in places such as California, Australia and southern Europe.

Areas with dry vegetation and lightning strikes are most susceptible.

Nature of a wildfire

Areas with dry seasons or semi-arid climates are most likely to be affected:

Parts of Australia
USA and Canada – including California & Florida
Southern Europe – including southern France, Italy, Greece, Turkey and Mediterranean islands such as Sicily, Cyprus, Corsica and Sardina

Nature of a wildfire

Fires can benefit ecosystems such as in Mediterranean climate regions and savannah grasslands. It can clear vegetation and help seeds to germinate. Certain plants are stimulated by fire and it can get rid of parasites and insects. Pyrophytic species can withstand fire, for example the baobab tree has resistant bark and the banksia needs fire to open its woody fruit.

Nature of a wildfire

Tropical rainforests didn’t used to experience wildfires as their climates were too humid, but as climates have changed and forest clearance has got out of hand, fires have burned out of control for long periods.

TASK:

Look at https://slaveevo.com/goto/?ai=3190 - working in pairs or threes look at information about fires in one continent. Which causes are most significant in your chosen continent? Produce a sketchnote to show this information - be prepared to share this with the class. Note key points in the table below: