Rescuing the bush
If you are lucky enough to have bushland on your property, then you have one of the great jewels in the landscape crown. At its best, bushland is a reservoir for precious biodiversity, a showcase of WA's floral renown and a connection to the wonders of nature.
Many bushland patches have seen better days - they may have been overrun with livestock, lost most of their plant diversity and become a haven for weeds and vermin and a fire hazard.
However, bushland is remarkably resilient and complex. After all, it has been evolving and diversifying in one of the world's harshest environments for millions of years. All it needs is for its land stewards - us - to recognise and reverse the trends of human disturbance. With the release from such bondage, bushland will regain at least some of its former glory.
_Quarantine matters _
Prevention is much better than any possible cure, and so keeping trees and bushland safe and healthy is always the best strategy. As a rule, never allow anything into your bushland that might cause it harm. And when it comes to harm, it doesn't come any nastier than Phytophthora dieback (Phytophthora cinnamomi, commonly known as jarrah dieback), Armillaria and Pythium.
These plant diseases are extremely virulent and common. They are found in all manner of items, from contaminated soil, infected mulches and potting mixes to the tiniest roots and the largest trunks of diseased trees.
They are also easily and unwittingly spread - the tread of shoes, tyres, hooves and paws to roaming roos can transfer infected soil into bush areas and around seedlings. That means no grazing animals, machinery, soil, gravel, mulches or building supplies should ever make it into your precious bushland, especially during the warm and wet periods of spring and late autumn when these diseases are most active.
_Quarantine strategies to reduce the risk of infection _
·Fence out all stock plus off-road bikes and vehicles, which can carry contaminated soil.
·Have set and 'sterile' entry and exit points to your bushland. This can be as simple as a short section of path constructed with limestone (this is the only soil type hostile to the fungus) and a footbath or tyre bath with bleach so you can dunk boots or tyres to kill the fungus. This will help prevent contaminated soil from entering a protected area.
·Have defined paths through your bush. This will allow you to enjoy your bushland while minimising the spread of potential contaminants. If the entire path can be paved with limestone, even better. Some bushland management agencies slash a one metre strip of the vegetation on either side of paths so that they become de facto emergency fire management tracks.
·Avoid drainage being directed into the bush. It could increase the chance of Phytophthora dieback, weed seed, chemicals or excess nutrients migrating into the bushland. For a remnant on a slope, a nifty trick is to put a grade or contour bank above it to catch and hold potentially contaminated water. You can even integrate a line or two of trees around this bank to take advantage of the extra water and nutrients.
·Only use seedlings from accredited nurseries for revegetation work. This is the only way in which you can ensure these plant diseases don't enter bushland through contaminated potting mix. This is a possibility when plants are bought from garage sales, markets and non-accredited nurseries.
·Be careful when using mulch. In an open paddock or in your gardens mulch is an indispensable ingredient in creating successful, drought-tough landscapes but there is a risk your mulch might be a carrier of plant diseases and so caution is needed before introducing it into your bushland.
If you need mulch for revegetation work, the best strategy is to chip up healthy in-situ branches and foliage to provide the mulch supplies, thus eliminating any chance of importing the diseases. If you must bring it in, ensure the mulch has come from a reliable source.
Ask the contractor to only provide fresh green mulch that has come from the prunings of healthy street trees or compost it for a month or two before use to kill off any residual disease. Reject anything that has soil in it.
I have spent a lot of time discussing weeds and their control, and their emergence and spread represent one of greatest threats to bushland. If left unchecked, weeds will choke out understorey and natural regeneration, out-compete critical diversity and stymie the regrowth and resilience for which bushland is famous.
Weeds will also greatly increase the risk of fire, which has implications for your safety as well as the health of the bushland. So get to know the weeds on your property and begin work towards their removal and replacement.
For more details and factsheets, go to
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