Garriga, maquia and fire

Fire as an agent of landscape change is not a subject that we consider much in New Zealand, even though we have an extensive history of its influence; both by deliberate and accidental means. As a temperate country with considerable amounts of rainfall (although this varies widely), we associate fire more readily with Australia’s environmental past and present.

However, fire has played a major role in our landscapes, dating back to the earliest period of human occupation, when the eastern side of the South Island in particular was ravaged by events that relate to (but were not confined to) what have gone down in oral tradition as the “fire of Tamatea”¹. Burn-offs are still a regular event in the South Island’s dry eastern flank, where it is used to decrease the prevalence of vegetation that impedes the movement of stock or people through the landscape (such as the notoriously spiky Aciphylla or matagouri).

These images, however, are quite clearly not of New Zealand, but rather Mallorca – where my friend and colleague, Carles Martinez (of Victoria University), conducted studies into the place of wildfires as an agent of landscape change. As part of our continuing series of field trips and lectures (which we undertake on a monthly basis), I flew Carles up to Auckland to talk to my staff and a couple of colleagues about his fascinating research into the ancient relationship that Mediterranean cultures have developed with fire. In the montages above and below, the aftermath of a fire event can be seen clearly in charred areas of the landscape.

Mallorca’s hot, dry climate has been especially prone to wildfires since human habitation began. However, much of Carles’ research focussed on what variables have changed for their frequency to have increased markedly in the preceding decades. Two of these pertain to land use, and how this has been altered. Firstly, Mallorca has undergone a shift from a comparatively diverse mosaic of land use (and, by extension, vegetation types) towards an increasingly homogenised landscape, in which fire is then presented with a more uninterrupted path through the landscape.

The second point that I will mention herein relates to the quotidian lives of Mallorcans, who traditionally removed a great deal of the dry ‘fuel’ (of fallen branches) at the base of pine woodlands as a resource (for firewood). This ‘fuel’ now tends to remain at the base of the pines, feeding the flames when fires start (mostly originating from the margins of towns). Furthermore, the very nature of woodlands affects their combustibility, with the rapid-growing pines being far more prone to the perpetuation and acceleration of wildfires than oaks.

Another aspect of Carles’ research is a process in which we are very interested within the context of our own landscapes and abroad – namely, the development of vegetation types whose composition is modified to a considerable extent by fire (such as the dominance of fire-induced woodland and shrubland in parts of Australia) or other effects of human settlement.

I have always been fascinated by the terms ‘maquis’ and ‘garrigue’, which are distinctive Mediterranean descriptions for plant communities that have evolved in response to hot, dry climates, shallow soils and human factors (notably fire). Both are transitional states in the gradual move towards woodland. However, they are regularly prevented from maturing into woodland by the occurrence of fire.

On Mallorca, they are known as ‘maquia’ and garriga’; with the former constituting a shrubland dominated by closely-spaced shrubs with a lightweight character (pictured above, and akin to much of what we refer to as ‘scrub’ in New Zealand) and the latter characterised by a more open composition and greater prevalence of herbs and soft shrubs (as pictured below).

As a final note, it was interesting to hear from Carles that restoration or enhancement of garriga is customarily carried out through direct placement of seed insitu, as demonstrated by the volunteers above – a very different methodology than the customary manner of restoration in New Zealand, where nursery-grown plants are generally planted out.