Environmental
Recovering Land After Bush Fire
The response of the environment after fire can be varied depending on the landscape before the fire, the steepness of the land, when the fire occurs, how hot the fire was and when and how ferocious opening rains are after the event.
Many examples of effects of a fire on the land were noticed after the Chatcup fire. Most of this area was cleared farm land with small patches of trees and remnant vegetation. When the trees and vegetation were gone, there were two main effects.
First was the loss of soil from exposure to wind; soil was also more vulnerable to erosion as the organic matter in the topsoil was also burned away. This soil is vulnerable to water erosion and the steeper the slopes, the greater the potential loss.
Secondly, the pumping capacity of the perennial native vegetation to keep the water table low was lost, thus salt was brought to the surface, probably for the first time. This effect is generally seen around the wheat belt where land clearing has been undertaken. Water quality measurements taken for the following months on the Boyagering brook after the fire show a gradual rise in salinity measurements.
After a fire it is very important to protect the soil from wind and water erosion and retain any vegetation, dead or alive, until after the opening rains have started.
In the catchment around the recent fires, many trees have survived and will resprout and quickly regain their pumping capacity. The main problem in this area is the steep slopes which will erode if we get some heavy rainfall before the native plants have had a chance to grow. So we hope the first rains will be gentle.
To prevent erosion, do not be in a hurry to remove fallen logs and branches if they are not causing a hazard or a danger. If trees are dangerous, then fell them and if possible leave them on the ground to protect the soil. Once the winter rains have allowed new ground cover to appear, the material can be removed well before the next fire season if they are close to the house. If you can retain logs away from the house for wild life refuge, please consider doing so. The soil will be dry and easily blown away so the protection of anything on the surface will be of benefit.
If there is not much onsite, you may be able to get some mulch in the form of straw or chipped bark to put on the ground. Make sure it is weed free.
First signs of life will happen within a few weeks when the re-sprouters (plants that have lignotubers) start to reshoot if the fire has not been hot enough to have burned right through their root system. Don’t assume that a tree is dead just because it looks dead.
Once signs of life appear, assess whether trees are in appropriate positions. Do not have large trees, especially eucalypts, within a 30m zone around the house. Once autumn rains start, the re-seeders will start to appear. Monitor the regeneration and eliminate Eucalypts tree seedlings and species such as Dryandra from the 30m protection zone. In other areas Dryandra may be useful as it germinates quickly and is good at holding the soil together.
Weeds
If there were no weeds at the site before the fire then they should not appear. However, some may have been carried in by machinery used to fight the fires or by hay brought in to feed animals. Try to feed animals in a confined area if you are uncertain about the hay content and monitor all areas for signs of weed growth once rain starts. It is a very easy job to control these weeds in the first year they appear but the task will become harder if they are allowed to seed.
Revegetation
The Toodyay Seed Orchard Group is able to provide native plants in tubes form the end of May at a low cost for all landholders who have lost vegetation around their property and wish to replant. If you would like more information or require a site visit please call 9574 5882 or email bethanlloyd_8@msn.com
Also, don’t forget to come to our fire recovery work shop on 11th April.