Fire back in favour as upland farm management tool
At the national hill sheep conference recently organised by Teagasc in Bantry, Co Cork, ‘Prescribed Fire as a Land Management Tool in Irish Uplands’ was a somewhat unusual topic.
Ireland has experienced an increasing problem with wildfires in recent years, with 2010 and 2011 considered catastrophic, due to over 1,500 hectares of forest being lost in both years, and up to 25,000 hectares of open land burned in each of these years.
Nevertheless, there is increasing recognition of the role of fire as a potentially positive land management tool, according to a conference presentation by Ciaran Nugent of the Department of Agriculture’s Forest Service, and John Casey, a Teagasc forestry development officer.
They linked the increased frequency and severity of wildfires to changes in the uplands which have resulted in less intensive grazing, and greater “fuel” accumulation.
There is a strong need to bring uplands back into active/ productive management, and traditional controlled burning techniques and traditions need to be updated in this context.
They said thorough knowledge of fire and its influence on vegetation under different conditions is essential for effective and safe prescribed burning. A high degree of co-operation between landowners and others concerned is also required.
Local-level fire inter-agency groups, such as those operating in counties Cork and Kerry provide a suitable forum for discussion and platform for improved co-operation, training and knowledge transfer, the conference was told.
Landowners were strongly advised to seek NPWS advice on habitat and conservation issues during the planning phase, and to notify the fire service of the intention to burn.
Landowners are obliged by law to notify in writing owners of forestry within one mile, and the gardaí, of their intention to burn.
The Department of Agriculture’s Codes of Practice for Prescribed Burning should be consulted.
Careful planning and preparation ensures objectives can be achieved, without causing wildfire outbreaks that may put lives and property at risk.
The legally permitted period for prescribed or controlled burning is from Sep 1 to Feb 28.
Land managers must consider what the desired outcomes will be in terms of vegetation treatment and transition. In most cases, the objective will be to maintain or favour heather species, over less beneficial species such as molinia, to provide the maximum level of nutrition throughout the year. This also helps to maximise habitats and minimise “fuel”.
If heather is not managed, it takes on a very dishevelled appearance and eventually breaks down in patches and dies after 25 to 30 years.
The most productive heather moorland is one with a patchwork at different stages of maturity. Prescribed heather burning should encourage new growth to sprout from existing heather plants, remove dead material, and recycle nutrients.
Heather can usually be burned once it has reached 30cm (about 12 inches). Care is required in stands of tall heather to maintain flame length within manageable limits.
Large amounts of coarse “fuels” in large woody plants brings the risk of difficulty in controlling fires. Over-hot fires will cause long-term soil damage. Burning in damper weather conditions may alleviate these issues — but it is preferable and safer to treat taller heather mechanically using a flail or swipe mower, where terrain permits.
Some patches of heather (and other heathland vegetation) should be allowed to remain and grow to over 40cm (about 16 inches) for structural diversity and to provide havens for wildlife. The aim is for such areas to cover 10% or more of the overall land area.
Mixed heather/ grass should be managed with a preference for heather conservation over grasses, preventing encroachment of less nutritious coarse grasses such as molinia.
Gorse species are problematic for prescribed burning due to their highly flammable and unpredictable nature. And burning stimulates gorse seed to germinate, resulting in greater spread at the expense of more preferred species for grazing or game management. Prescribed burning of extensive areas of gorse should be avoided, in the absence of suitable preparation and effective control lines.
Molinia molinia, juncus and other grass species will burn easily and rapidly when dead in spring, and can dry out to flammable condition quickly after rain, where wind conditions permit. A coarse grass, molinia has colonised many upland areas thanks to improper burning techniques and consequent decline of heather. It can be very problematic for fire control due to burning windborne fragments spreading in windy conditions.
Molinia is highly digestible, and provides suitable summer grazing, but its limited May to August growing season provides inferior winter grazing nutrition. Maintenance of optimally aged and structured molinia and heather cover is vital for successful winter grazing. Reduction of the dominance of molinia and an increase in dwarf shrubs, especially calluna, is recommended.
Bracken bracken should not be controlled using fire. Bracken spread will be stimulated by burning, and controlled burning of dead bracken is notoriously problematic, due to its high flammability.
With the recent delisting of asulam as an approved herbicide, chemical control for bracken is now also severely restricted. Where bracken is an issue, alternative prescribed grazing or mechanical control measures should be employed.
