August 14, 2018
Merewyn Groom

California fires

As a volunteer firefighter I keep an eye on wildfire related events around the world. In thinking about the Californian fires I’m struck by the similarities and differences to the Wellington bushfire situation.

In some cases the similarities have led to opposite effects.  Right now Californian firefighters are battling the Mendocino fire, the largest ever recorded and about 19 other separate fires, the situation is so serious a state of emergency has been declared.

Unfortunately the current fires in California are part of a worsening trend with the fire season starting earlier and the fires becoming larger. In the year to date CALFIRE & US Forest Service have responded to a staggering 4,723 fires.

The economic cost is staggering, homes and businesses burnt, recreational areas destroyed, people’s lives interrupted through evacuations, and every year people lose their lives. The resulting air pollution can cause health effects over a wide area and can even disrupt air traffic.

Firefighters travel from other areas due to reciprocal help agreements where resources are shared in a cooperative effort. Firefighters also come from overseas, right now NZ has deployed people to help in Canada where they are also experiencing a serious fire season.

During my 20 year involvement in Wellington I have seen the number of fires here steadily reduce, and we haven’t had a really big one in several years. A fellow senior firefighter commented to me that “now days we put them out before they get big”, and it is true that upgraded equipment and new technologies such as fire suppressant foam have significantly improved our response time and  firefighting effectiveness.

The main physical difference is that the native Californian forest is very prone to burning, in particular the chaparral shrub land. Fire is such a key part of the ecosystem that many chaparral plant species require a cue from a fire for their seeds to germinate. Before the establishment of farms and cities, the forest would naturally burn off in a 20-30 year cycle. This is the ecosystem’s way of managing pests and enabling regeneration.

In contrast the NZ native bush is rather lush and fire resistant. The main fire danger around Wellington has come from introduced species, predominantly gorse which burns about as readily as the chaparral. Gorse became established on our hills after the native bush was intentionally burnt off for farming.

Ignition points for Californian fires are very varied, from lightning to car crashes or a torn tire spat off a passing truck. The environment is such that a simple spark can be enough, and combined with the dry Santa Ana wind (the local equivalent of a Nor’ Wester) small fires quickly become big ones. Currently people are pointing the finger at electricity lines companies, and there are many threats of legal action as you would expect from the US legal environment.

Around Wellington the vast majority of bushfires are started by arson. Often bored kids, there have also been adult serial arsonists. The removal of skyrockets from the market had a major effect at reducing fires around Guy Fawkes, and the total number of accidental bushfires. A few years back we did attend one inadvertently lit by the Silverstream Steam Train.

Changes to the urban landscape have had an effect. Housing up to and within forested areas has certainly increased the economic and social cost of wildfire in California. The build-up of housing around the fringes of the Hutt Valley has had the opposite effect, with reduced opportunity for arsonists to access the hillsides.

Like us, the Californians have traditionally built their homes from wood, but unlike NZ the common roofing material used up until about 50 years ago was wooden shingles, with predictably disastrous results. Reluctance to control people’s choices through regulation was eventually overcome, resulting in requirements to build in a less flammable style.

Increasing fire risk is being linked to climate change. Certainly any area where rainfall is reduced and temperatures rise will experience increased fire activity. Perhaps ironically it was environmental concerns which brought a halt to pre-emptive burnoffs to reduce the amount of available fuel in California.

In Wellington there was no active effort to supress bushfires until volunteers formed the Wainuiomata Bushfire Force in 1970. Being funded through an insurance levy, the mandate of the Fire Service then was to protect people and private property, so they defended the urban edges and allowed the hillside to burn. This resulted in the gorse re-growing and eliminated the chance for native bush to regenerate. We now understand that the gorse plants create a nursery environment for the native seedlings to become established. The natives ultimately overtop the gorse and shade it out. Through this process, the native bush replaces the gorse if it is left undisturbed. Following the establishment of volunteer Rural Fire Forces, the fires have been increasingly efficiently contained and extinguished. The huge amount of native regeneration we now enjoy is a direct result of that effort.

For Wellingtonians the future is increasingly leafy. In California the locals are going to have to either learn to cope with more fires, or take some drastic action to reduce the fuel load in their forests. Either way there will be major environmental and economic impacts.