Learning to Burn
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Learning to Burn
Learning to Burn
Module Objective: How to identify the hazard, risks and key assets on yours and neighbouring property.
There are three aspects to consider
Risk Risk has two elements, i.e. the likelihood of something happening and the consequences if it happens
Asset Anything valued by people which includes houses, crops, stock, fencing, forests and, in many cases, the environment.
Hazard Any situation with the potential for harm to persons or damage to resources and assets. This includes the fire environment (fuel types, weather, topography and ignition sources)
When assessing fire risk, it’s actually the small stuff that causes most concern.
What we call ‘fine fuel’ – dead leaves, twigs, bark and sticks – is the most significant contributor to the spread of a wildfire.
While tree trunks and logs do burn and add to the intensity of a bushfire, they don’t help it spread to unburnt areas. So areas with logs, trees or short grass do not pose as great a hazard as areas with a dense shrub under-storey or a deep layer of leaf litter, and that affects our decisions.
But we also factor in environmental considerations and will exclude vulnerable areas or take certain steps to protect key areas. It’s quite a balancing act.
Undertaking burn site preparations in advance will enable burning opportunities to be taken when they arise and will contribute to sound risk management. Leaving site preparations to the last minute is poor practice, as this can result in (often limited) windows of safe burning opportunities to be missed.
Burn planning must consider areas that could be risky if a fire might escape (topography and weather). In addition, consider tenure to identify who needs to be notified of a burn, or what co-operative arrangements with landowners might be required to ensure both properties are safe.
Weather is an important factor to consider when planning your burn. It can change quickly and can catch you out.
[Click Here!](https://fireweather.niwa.co.nz/) –> Click Here!
Understanding the burn site
Topography has a significant influence on fire behaviour through slope, aspect, elevation, and landform. Topography within and surrounding the burn area will therefore be an important consideration when planning ignition patterns you should use, and how you anticipate variations in fire behaviour that can cause the fire to accelerate and jump firebreaks and barriers.
Smoke hazards
Identify any ignition activities, active burning or smouldering that may occur as a result of your burn, between the period of 1-hr before sunset to 1-hr after sunrise. These are the times when smoke problems are most likely to occur and impact on neighbouring sites.
Also note the conditions most conducive for smog formation, which typically occur from late autumn to late spring, when ground and water temperatures remain warmer than the nighttime air temperature.
Identify any pockets of woody fuels or heavy duff layer or peaty soil that could burn and smoulder for long periods of time.
Identify potential smoke sensitive sites, especially highways, open waterways, down drainage from the burn and within a distance (from 3-15 km from the burn) that smoke could flow into during the night? The steeper the topography, the further smoke can travel.
Are any stock (yours or neighbours) in the line of smoke drift that may need to be moved prior to conducting your burn?
Identify any structures or vegetation (trees) that would funnel smoke towards or into drainages.
Include smoke management strategies (avoidance, emissions reduction, dispersal) used to minimize adverse impacts at these sites. Attach the smoke management plan (e.g. screening system calculations) as part of the burn plan.
Determine where and when individual areas will be burnt or protected
Individual areas to be burnt (burn plots) should be clearly marked out on a 6‖ OS map or DAF Morthophoto(aerial photo). This will help ensure that effort and resources are applied most efficiently and effectively. Identify on the ground areas where there is the potential for loss of control or damage to neighbouring assets. Such areas may consist of steep slopes where fire control may be problematic or particularly flammable vegetation such as bracken or gorse scrub patches. These areas should be considered fire-free and adequate measures taken in advance of burning to ensure they remain so.
Identifying and protecting assets
The burn plan should identify any values and assets that require special attention, and may include methods to protect them during burning. Some precautionary measures can be made early during pre-burn planning, such as manual reduction of vegetation fuel from around significant sites, and establishing firebreaks and temporary control lines near assets such as outbuildings.
Identify Fire Free Areas
The first step in planning must be to identify areas where burning would be harmful or simply a waste of resources. Areas within which burning should not take place may contain the following:
When planning a burn-off it is essential to identify the assets that are around the urn site. What are other valuable assets that you need to protect should a fire escape? E.g. property, structures; stock; neighbouring sites of significance; crops, forests, orchards and other valuable vegetation. A good place to start is creating a map and marking on the map these locations. Some assets include:
Identify these areas and make them known.
Managing the protection of adjacent values
Prescribed burning is part of a range of activities that help protect primary industries from larger wildfire risk. However, burn-offs can have an impact on:
Think about where you want to have the fire. If your burn is going to be on or near a boundary that is close to high-value commercial plantations, crops, areas of public conservation land or other farm infrastructure, you should advise your neighbours. Seek expert advice on identifying and protecting ecological values from fire. The best way to protect ecological values is to burn under appropriately mild conditions. However, sometimes additional measures will be required.
Also be aware of other national infrastructure utilities that are present:
Determine actions that might be required to manage any hazards identified. For example:
| Identified Hazard (e.g.) | House to the east of burn site | Fence posts and habitat trees |
| Action required to manage hazard | Inform occupants of intention to burn. Leave a buffer to the house. Use a wet line or lighting pattern to control backing fire entering the buffer area. | Use either a rake hoe or foam around habitat trees and fence posts if required on the day. |
Burning in appropriate conditions is the key strategy for ensuring built assets are protected. There are a range of strategies available for protecting ecological values such as planning ignition to back fire away from fire-sensitive areas, raking around habitat features, rake-hoe lines or wet lines, erosion control measures.
Ensure that there are effective firebreaks/control lines
Identifying firebreaks is an essential part of fire planning-no fire should be started until you are certain where and how it will stop. Firebreaks must be 2.5 times the planned flame length. Flame length will be a function of vegetation type and condition, in addition to prevailing weather conditions at the time of burning. Typically, firebreaks for most moorland/bog types need to be at least 6meters (about 20 feet) wide to reliably stop a fire under controlled burning conditions. Be aware that some forms of vegetation can give rise to windborne firebrands and cause fires to cross firebreaks in strong wind conditions.
Check that your selected control lines are still serviceable- it may have been a few years since you last burned. Can vehicles still gain access to the site? Check for any fallen or hazardous trees, track washouts, and that turn-around areas are still adequate. Also check the status and accesibility of water points on the property – what are the water tank levels or dams like? Check the status of safety zones, and that escape routes are clear of fallen rocks, hidden objects, holes and overgrown vegetation or overhaging branches.
Fuel piles resulting from control line estalishment or maintenance can also create hazards during the burn and may require redistribution or pile burning seperately prior to the main prescribed burn.
Resources Involved
Ensure you have adequate communication devices for all the crew, and also that each member has adequate PPE and manual suppression equipment is readily at hand. Also consider the suppression equipment required to combat any escapes.
Activity: Identify the hazards and assets on your property and neighboring lands.
Self-Check: What would you do to minimise the risk of a fire escape?
Q. What are some of the values and assets that could be affected by your burn off?
Q. what are the best ways to identify values that could be impacted by your burn?
Q. What are some possible action that may reduce the level of risk from a fire escaping?
Q. Why is it important to check the boundaries before burning?
Q. Why is it important to considering neighbouring lands other than the area being burnt?
Know why it is important to identify hazards, and how to mitigate damage to assets.