Understanding Fire History

Understanding the history of fires that have occurred on country you are managing is very important. It helps guide your understanding of areas that are burning too much or to identify a country that maybe needs a fire. Helps you to work towards developing healthy country and by guiding your burning strategy. 

You can use the NAFI interface to download some of the fire history data so we can better understand what’s going on. By downloading the data we have more flexibility to change colours and to show only areas we are interested in. These data are also included in the data folder provided for today’s tutorial. Skip to Exercise

To download fire history from NAFI go to www.firenorth.org.au:

  • Select the ‘Data’ tab
  • On the left-hand-side menu select ‘Geotiff & Shapefile’
  • From the options below select your desired fire history type

A window will open with further options. You can download either an Image (raster) file or Shape (vector) file for each option by clicking on the desired button.

A window will pop-up – save the file to your desired location.

Go to the folder location. Right-click on the Compressed (zipped) Folder and select ‘Extract All’ then the ‘Extract’ button.

Making a fire history report map

It can be useful to display all these maps together to assess how you are going with your fire management and to inform planned burns. Skip to video.

Why fire history maps are important

We are looking at these three fire history maps because:

  • Fire frequency shows areas that are vulnerable to burning. Areas with a high fire frequency will have two characteristics that enable them to burn. the first is that they will be regions that support the growth of enough grass fuel to burn year in consecutive years. They will also be areas that are likely to have an ignition, either from a road or via lightning or just carry fires well with an incendiary drop.
  • Late dry season fire frequency is important as it highlights areas that might be getting to many hot fires. It’s important to reduce the amount of these hot fires.
  • Time since last burnt gives as an indication of those areas that may have accumulated a lot of fuel.

When thinking about the fire history it is good to also think about the type of country that is burning and how they respond to fire in different ways. For example the way that fire behaves and fuel accumulates will be different on lowland plans compared to the top of rugged escarpment country.

Load the NAFI fire history data.

The fire frequency layers are coloured by the number of times an area has been burnt.

The time since last burnt layer is coloured by the number of years since it was last burnt.

Make some fire history maps

To make a nice map of these fire history layers use the map layout tool: select the ‘Project‘ tab then ‘New Print Layout

Give your map a name and select ‘OK

A layout window appear. Use the ‘Add Map’ tool to draw the the map extent in the layout window.

Use the add ‘Legend‘ tool to add a legend:

You now need to edit the legend to remove all the items that are not important. Find the ‘Item Properties’ tab to the right-hand side of the map layout and start editing the legend items.

  1. Deselect auto-update
  2. Select an item you want to remove
  3. Press the subtract button

With just one of the fire frequency layers remaining click on the layer’s drop-down button.

Select all the values greater than 10 by clicking on 11; drag the side slide-bar down until you see 255; hold down the ‘Shift’ key and select 255. Remove the highlighted items by selecting the subtract button.

Your scale bar will look like this:

Change the legend text: In the legend items double-click on the ‘Band 1 (Palette) text – this will open a box where you can delete and change the text to ‘Times Burnt’

In the legend Item Properties find the ‘Background‘ check box and deselect it. This will make the map appear near the legend.

Change the layer name: In the QGIS layer window open the fire frequency properties window and change the layer name to ‘Fire Frequency’

Your legend should now look like this:

Now add a scale bar:

In the “Item Properties” window increase the segment numbers to increase the size of the scale bar.

Finally add a title to your map using the text tool:

Change in the ‘Item Properties‘ window:

  1. change the text
  2. Edit the font size and colour etc..

You should end up with a fire frequency map like this:

You can now save this map for use in a document or a presentation: select ‘Layout‘ and ‘Export as Image‘.

Changing the displayed map layer in the main QGIS map window allows you to also change the map displayed in the map layout window, try changing the displayed layer to late dry season frequency:

Back in the map layout window use the refresh view button to see the late dry season fire frequency.

Now change the titles to reflect the new layer type and save this as a new map.

Finally, before we finish looking at fire history information save your QGIS project. This will allow you to open it again at a later time and all of your layers and map layout will appear as you have it when you save it.