The gorse fire cycle

27 06 2010

Even before the big fire on the heath today I was researching the gorse fire cycle and had collected some photos from the common showing the various stages of the cycle.

Gorse is always closely associated with fire,  gorse was traditionally collected from Rushmere Common as fuel and it was often used in bread ovens and. When gorse is not proactively managed it will eventually catch fire in an uncontrolled way and the longer the period until that fire the worse it will be. Arson is an obvious source, however even without deliberate burning there are other ways that a fire can start accidentally or naturally.

The Gorse article on wikipedia says:

“Gorse may grow as a fire-climax plant, well adapted to encourage and withstand fires, being highly flammable, and having seed pods that are to a large extent opened by fire, thus allowing rapid regeneration after fire … Typical fire recurrence periods in gorse stands are 5–20 years.”

The RSPB says:

The accumulated dead material also presents an increased fire risk… Cut gorse to ground level and remove or burn the arisings. Also remove the accumulated litter of dead plant material as it is highly flammable

I checked out the heath today and took photos of the different stages of fire cycle which confirmed the quoted articles:

1) Here is what the gorse looks like immediately after a fire (the one today):

Ground still wet after fire is put out

2) After a few months a plant layer is starting growing back:

A few months after a fire

3) And then the gorse starts to re-grow from the base. Notice that heather is also growing well:

New gorse starting to grow

4) and gains height….

Growing fast and gaining height

5) It grows to full size…

Mature gorse

6) And then becomes leggy and starts shedding branches, which die, fall and start to build up the material for the next fire. Gorse is very brittle so breaks easily.

Older gorse shedding branches

7) Large amounts of material builds up at ground level over time.

Large amounts of dead material building up

The conditions are now set for the next fire, and indeed the longer it is left to build up the more serious the fire will eventually be, hence the advice to manage gorse to remove this material mechanically or by controlled burning before this happens.

I understand from a conversation with the commoners’ committee last year that they used to do controlled burning on the heath but that they don’t any more.

What does seem clear is that we will continue to have serious uncontrolled fires on the heath at regular intervals until some more effective management is done. The RSPB recommend that:

“Where discrete patches can be completely isolated from other habitats, they could be burnt in situ, although extreme caution is required as gorse is very flammable.

On the heath this does seem to be the case, especially as the gorse is separated by the fairways and could be managed into such areas – possibly this is being done, I will again ask the committee what their strategy is.

I note that the Rushmere Commoners’s 2009 AGM report mentions that the committee meet with the fire officer and manage fire breaks and access for fire appliances (but it mentions nothing about removal of material or controlled burning):

Firebreaks continue to be cleared and the Warden has recently met with the fire officer to discuss further work to assist access by fire vehicles and widening of breaks.

Before I sign off, this is clearly not just a local problem. Here are some gorse fires in the news in other parts of the country over the past few days.




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