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Share your experiences, questions and projects related to fire and weeds here.
Perhaps you have experiences, opinions or ideas to share related to the following questions:
- What are your experiences with integrating fire and weed management?
- What monitoring measures should be put in place pre-burn to enable post-burn monitoring of vegetation to be most effective?
- What pre-burn activities can be used to help manipulate the intensity of a proposed burn to maximise weed control outcomes?
- How is it possible to reconcile more frequent burning than is suggested by the fire threshold guidelines with the desire to use fire to assist weed management programs?
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Thanks for getting this up & running Greg.As a starting comment, I’d like to highlight the importance of rabbit control when seeking to use fire as a restoration tool in long-unburnt native vegetation. Our experience when studying the impacts of fire (a Hazard Reduction burn) on biodiversity in senescent Eastern Suburbs Banksia Scrub indicates that not only do the rabbits destroy newly emerging native plants. They also lead to a greater density of weeds in burnt plots that are open than in plots protected by a rabbit-proof fence. Our assumption is that the rabbits spread seed in their fur and faeces but wondering if others have related data or observations? Judy Lambert (North Head Sanctuary Foundation)
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Like native plants, weeds have a range of fire responses. They may be killed by fire and need to regrow from seed or are able to resprout from protected buds.
Response depends on fire intensity. In my experience a hot wildfire can kill a lot of Lantana but a prescribed burn is unlikely to be hot enough and resprouting is likely.
A fire needs to be hot enough to kill the obligate seeders and stimulate germination of seed banks.
Some good work has been done in the Blue Mountains treating Broom and Gorse seedlings in fairly remote areas after bush fire. The fire caused nearly all the seed bank to germinate and post fire control removed most of the seedlings before further seed production. The same fire killed large numbers of Radiata Pine trees and wildlings in an abandoned plantation. Follow up treatment of survivors and seedlings has dramatically reduced pine abundance.
But the herbivore and competition issues Judy raises are important. Weed control needs to be delayed until it is possible to work in the area without destroying too many native seedlings and most of the weeds are visible and identifiable. The appropriate timing is very site specific so monitoring of recovery after fire and acting at the right time is critical. -
Hugh, your response about the heat of a bushfire being necessary to either kill the existing plants and/or trigger sufficient germination in Lantana and other species, and a prescribed burn not generating enough heat, is a common observation by people involved in bush regeneration work. With Lantana I have observed a combination of herbicide/prescribed burn/follow-up herbicide being used to help the fire to do its job.
Is anyone aware of instances where prescribed fire has been intensive enough to successfully reduce weed density such that follow up herbicide application of existing parent plants can be minimised, and concentrated on seedlings that have germinated post-burn?
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Hi Greg.
I’ve had a lot of success using fire to manage weeds with a focus on the interface when establishing and maintaining bush fire asset protection zones and preparing Hazard Reduction burns. There are broad benefits in managing these areas using an integrated, land management focus rather than purely ‘fuel’ management however regular and well-times maintenance is required which can be difficult with competing priorities for many land managers.
With previous experience working in local government, some Councils have more flexibility in managing sites requiring intensive weed control with the opportunity to focus substantial time on heavily weed infested sites. In many cases this involved creating large numbers of pile/windrows for burning which promoted a flush of weed growth that could be treated prior to setting seed (we created & burnt ~250 piles per year). Ongoing maintenance focusing on hand-weeding created great results which even the bush regeneration teams used visit and assess. Unfortunately this is more difficult to achieve for other agencies with limited field staff and funding linked closely to bush fire mitigation. The use of contractors can also create difficulties with works having a definite start and end date and follow-up works limited to available funding in the following financial year.
Organisations that allocate suitable funding for minor maintenance enhance opportunities to undertake follow-up works throughout the year which results in significant savings for future maintenance and progressive improvements on the biodiversity of sites. Engaging contractors more consistently also increases efficiencies as the teams have a greater link with the sites and are able to plan and quote for works with a longer-term focus. Obviously not every site requires this level of integrated management as heavily disturbed sites in gentle terrain can be merely slashed – the more integrated works are best implemented on sites with difficult terrain or close to riparian or drainage areas.
While I have been managing sites in this way for over 10 years in the Hornsby/Ku-ring-gai area, in the last 3 years I have been able to implement works in Sutherland with a focus on control of intensive weeds plumes containing established species such as Privet and Lantana in interface areas for establishing APZ’s and prior to Hazard Reduction burns. Some sites have had as many as 40 piles created adjacent to a few as 8-12 houses which the RFS burn prior to the HR burn and additional follow-up weed control undertaken by contractors. This type of work ensures the weed infested areas are actually treated, as in many cases large weed plumes do not burn in the conditions that HR’s are undertaken, but are likely to burn in wildfire conditions. In addition the weed plumes are likely to invade the adjacent bushland following a HR burn, extending the area they cover and the future problems of trying to manage them as fuel.
While I have always struggled to find the time and resources to monitor sites where I have used fire for weed management, I have always taken pre and post works photos and can easily illustrate the success where follow-up works have been achieved. The greatest challenge is managing funding and illustrating the long-term benefits (environmental and financial) of a more integrated approach to fuel management.
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Hi Tim,
Port Macquarie Hastings council has started the ball rolling to develop internal capability to undertake pile burns and small scale HR’s. I have been implementing post HR weeding to ensure no increase in weeds or loss of ecological health. I am lucky that I utilise the same contractors each year and thus that familiarity with the sites means cohesion and early detection of weed issues post burns.
I also would be thrilled if more intensive monitoring could be regularly undertaken to collate data on the effectiveness of the integration of fuel load mitigation and weed management.ps. Do you know of any keen students willing to do this every year for free?
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Comments on article: Flame Weeding to Support Restoration
Navigating legislation and trying to do the right thing involving fire can often be a minefield. Here are a few extra points contributed by the NSW Rural Fire Service that may provide some clarity for flame weeding activities.
• It is important to clarify that the intent of flame weeding is not to ignite vegetation. The live flame generated by the weeder should not cause flaming combustion of vegetation but the heat generated causes enough cell damage to kill the weed.
• A permit may not be needed to undertake flame weeding. Some clarity around fire permits is given below:
Under the Rural Fires Act 1997 Bush Fire Safety permits for burning in the open are required:
o To conduct any burning during the Bush Fire Danger Period
o If you light a fire that is likely to be dangerous to any building at any time of year.• Some local government areas require permits under the Protection of Environmental Operations (Clean Air) Regulation 2010
• The Rural Fires Act is silent on activities where a fire is not actually lit. This would indicate that the onus is on the operator to ensure that the use of the flame weeder does not cause a fire to be lit.
• It is always advisable to have a conversation with the relevant fire agency (NSW Rural Fire Service or Fire and Rescue NSW) to seek advice about fire safety depending on your location, time of year etc. as suggested in the article.
• In terms of other approvals, if the purpose of the works is not for bush fire hazard reduction then you won’t need a hazard reduction certificate but you may need another environmental approval if required by any other law.
• Some other safety considerations:
o By default flame weeding is prohibited during a total fire ban day (it would be classed similar to hot works like welding as it involves the use of a naked flame).
o You should check whether a Total Fire Ban (TOBAN) is in force: https://www.rfs.nsw.gov.au/fire-information/fdr-and-tobans
o It would be advisable that when using a flame weeder at any other time that you have adequate firefighting equipment in working order available on site. As a minimum this would be (guide only):
16L knapsack spray pump filled with water; or
9L liquid fire extinguisher; or
0.9kg dry powder fire extinguisher.
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