Earth & Sky

The following individual was interviewed for today’s show. Our thanks to:

Dr. Stephen Pyne
School of Life Sciences
ASU
Tempe, AZ

Links:

FAO, Forestry, and Fire

Interview with Dr. Stephen Pyne:

SP: I’m Steve Pyne. I’m a professor in the Biology and Society program at Arizona State University.

ES:

SB: Sure. Well, I have long been interested in fire. Fire is something that human beings as a species have a monopoly over, at least as far as it’s manipulation goes. It’s a pretty good index of who we are. It’s what we do that no other creature does. I mean, other creatures knock over trees, dig holes in the ground. We manipulate fire. And I started in the U.S., and have gradually been expanding that study around the globe, and have most recently tried to put into a similar format, sort of, everything I knew in 200 pages in a book called, “Fire: A Brief History.” I guess we could say, beyond that, fire is fundamental to the earth. It’s a creation of life. Life created the oxygen. Life supplies the fuel. Once it’s established on land, and lightning has been a more than adequate ignition source. But life even claims that in the form of our cells, since we close that cycle between life and fire. Fire’s been around for 400 million years or more, people didn’t invent it. We’ve certainly changed the way that fire appears on the planet. Fire looks the way it does on earth today because of what people have done and not done, the ways we’ve started fires, the ways we’ve stopped them, or tried to stop them, the ways we’ve moved fuel around. That is to say, we create fuel and can put in fire where it would not naturally occur or under different rhythms or patterns, what you would call regimes. And, more recently, by tapping into fossil biomass, we’ve escaped the whole ecology of earthly fire, as it’s existed for several hundred million years, and we’re introducing a whole new ecology, a fire ecology based on the combustion of fossil biomass. And that is the deep driver of fire history on the planet, and it’s something that we understand very poorly.

ES:

SP: Let me create the setting here. How did people become fire creatures? How did we acquire that fire power? First, by controlling ignition. And people can become surprisingly powerful by controlling ignition in areas that already have fire, or areas that have the conditions for fire, but lack a consistent ignition source. Mediterranean climates for example don’t have lots of lightning caused fires but have ideal conditions. So people can be very effective in taking over these regimes, and so forth. But they’re still limited in what nature presents. And the next phase is that when we begin controlling fuel, living biomass. And this is basically, for fire history what agriculture means. You begin growing it, you begin cutting it, you begin crunching it with livestock. You put it in a form that can burn, quite outside the “natural patterns” of fire. And then you can apply ignition. Otherwise, if you apply ignition to fuel that isn’t in a condition to burn, nothing much is going to happen. So we expand enormously the range of fire, its patterns, its geography, and so-forth. But that’s still limited by what nature presents, it’s limited by what you can grow, and while you can come in and slash, create lots of fuel, have terrific fires, you can’t keep doing that. You can discipline it into a pattern of regular field burning, rotational burning, and so forth, but there is still limits. We’ve evaded those limits, in what we call industrial fire, we’re tapping into fossil biomass here. Now we’re getting the things that we got from fire, we are now, by burning living biomass in some form or another, we are now getting by burning fossil biomass . That also means that we are removing fire from many landscapes that had known it in the form of human burning or regular burning. So fire has basically gone out of domestic situations, and that may be all for the good, the real public health issues. Fire is gone from most manufacturing and industrial – open burning is – situations. It’s very rapidly going in the developed world, in agriculture, that we’re no longer burning the fields, we no longer grow the fallow. One of the consequences of that is that the fallow is where the local biodiversity was. But one of the ways, if you wanted fire in agriculture, you had to provide the fuel. The way you provided the fuel was by growing it. Getting it in some form to the field so you can burn. That process of fallowing is very rapidly going. So that we now go to industrial fertilizers, pesticides, herbicides, tractors, all of these sorts of things, to take the place of fire. We’re just sort of removing open flame from the landscape. And that, as it turns out, has ecological consequences. And industrial societies began pursuing open flame everywhere. This is sort of an odd circumstance, but it seems to hold, at least in the early decades of development. And so you began applying this sort of internal combustion engine to the outright suppression, not simply the substitution of flame, but the outright suppression of it. So that the ecology of the planet looks very strange. We have too much fire in some places, too little in others. Probably too much combustion. The earth doesn’t seem to be able to absorb all the fossil biomass burning that we’re doing. But we don’t really understand this larger ecology. How is it that human beings – people who have been the keepers of the flame for the planet – when they begin shifting their controlled combustion into fossil biomass, what are the larger ramifications of that? Well, we’re thinking greenhouse gasses, global warming, it ripples through all kinds of other ecosystems because you’ve changed the way fire appears on those other lands. And that means that plants and animals – biotas – that have adapted to a particular may no longer be adapted. And this has all kinds of consequences. we can destroy biodiversity just as surely be removing fire in places that have frequently known it as we can by putting it into places that have not known it. So there’s really no way to evade our role. There’s no neutral position. Fire can be just as ecologically powerful removed as applied. And we don’t understand how our transition into industrial fire is affecting that larger ecology of fire on the planet.

ES:

SP: Well, let’s start with plants, because animals basically adapt to fire in terms of the habitat. That is very largely set by the plant, although the animals are very important in shaping the character of the plants. So I suppose one of the best studied is in the American West, the Ponderosa Pine Forest was very nicely adapted to very infrequent, low intensity ground fire. And these tended to grow as large trees, almost in kind of a savannah-like context, with largely a grassy understory. Fire would sweep through the base. It has thick bark, its swept off that heat pulse easily enough. It prunes itself of lower branches, most of the canopy and the sensitive stuff is way above. And so it’s very nicely adapted to all this, and actually may require certain patterns of fire to regenerate and so forth. But suppose that you change that pattern of fire. So, suppose the light, frequent fires are remote. The place begins growing up, because one of the things those fires did was flush it out periodically. It becomes heavily overgrown with woody plants, lots of reproduction. Now if a fire gets into it there’s a lot more to burn than there used to be. You have pine needles, branches, lots of small trees, and in effect a brush layer at the bottom. Fire gets into that, and then it may even be able to get into the canopy. And you’ve changed from one fire to another. You’ve changed the regime. You now have larger, more intense fires. They may even burn as crown fires, that is through the canopy. And this tree is simply not adapted to that. It was adapted to another pattern of fire. So you have something that is used to a pattern of rainfall , in which rain falls more or less evenly every month. The form of precipitation may change, maybe it’s snow or whatever, bit it’s more or less constant. And then you shift it. You give it 20% as much precip., and it all comes in one month. Well, it’s not used to that. Or even if you kept the same amount of precipitation but put it all into two months, huge thunderstorms or deluges. It’s simply not adjusted to that. And that’s pretty much what the analogy to fire would be. So, animals have lots of ways of accommodating fire. Many animals burrow. They simply go underground. They survive the passage of the flaming front. Animals that can fly take off. Animals that can run, run away. There are always some animals that are going to be trapped. But this image of animals instinctively terrified of any kind of flame is just nonsense. There’s good reasons to be frightened of high intensity, forest scouring fire. So that’s a very apt response. But for the most part animals simply accommodate and get out of the way or in fact exploit it. And you can see for example in Northern Australia, where a bush fire is progressing it sets into motion a kind of fire drive. And so it stirs up a lot of small creatures. It puts into motion a lot of insects, animals come in to feed on those right along the perimeter. Insectevoirs, birds come in and start picking off all these insects that are liberated. The whole food chain moves up, and you get kites and wedge-tailed eagles picking off the birds and the other animals. And then when the fire stops, the larger birds around simply go to the next smoke. So this idea that animals have some intrinsic fear is just nonsense. But again, the animals are adapted, if you will, to a particular arrangement of vegetation, and a particular kind of fire. That kind of fire I just described suits them very well. But if you were to change that fire, then suddenly it doesn’t work any more. And animals can certainly be influential in shaping the character of fire. If they graze very heavily. If they’re large herd animals and they graze very heavily, then there’s less stuff on the ground to burn. They change the pattern of burning. If they graze stuff low to the ground, they change the pattern of fuel and brush. If they force the canopy to rise very high, then that changes the pattern of fire and so forth. So they’re very much an interactive part of it – not directly with the flames – indirectly in how they shape the vegetation.

ES:

SP: Climate is of course one of the fundamental shapers of fire. The ideal climate for fire is a pattern of wetting and drying. That is to say, what you want to know is how frequent, and how intense are the wet and dry spells. So, many places go through a wetting and drying cycle every year, which is to say they have and annual fire cycle. Well, it has to be wet enough to grow stuff, and then dry enough to prepare it to burn. So desserts, for example, tend to burn after unusually wet seasons because that puts fuel on the ground that normally is not there. Whereas, places that are normally wet burn – particularly after dry periods – because that’s the only way that the fire can combust that material. So the patterning – sometimes this happens annually, sometimes this happens over a period of several years – this whole ENSO phenomenon or La Nina/El Nino phenomenon in much of the American west, for example that pretty well tracks fire. The biggest fires seasons are those that are dry after a period of wet runs. So you’ve had several years to build up everything, well it suddenly turns dry and you’re ready to burn. In places where there is a very violent fluctuation, places that are normally very wet, suddenly and unexpectedly turn dry. Places that are very dry suddenly become flush with water and all kinds of ephemerals and such sprout up. And that’s what we saw in the last major El Nino, say around ’97, ’98 and so forth. So in the long turn, that’s really what you want to know about fires. Some of the wettest places in the world burn every year, because they also turn dry. So, what’s unclear about the future of fire here is whether places that are now normally wet and support large forests are going to become dryer, and during that drying period become vulnerable to fire. But even moreso is the pattern, the fluctuation how large an amplitude. Is it going to be really wet, and then really dry? Is that going to happen suddenly or over a slower period of time? That’s what I would want to know about future climate and how that will affect fire. And of course, we’re up to our ears in all of this – starting fire, trying to stop them, logging, clearing, rearranging the vegetation, doing all kinds of stuff that can amplify of calm those conditions. So in the larger sense of global warming, it is not necessarily that global warming leads to more fire, it will be a case of whether that leads to a more intense pattern of wetting and drying, the frequency and intensity of all that. That’s what I think will determine the future.

ES:

SP: Well, the present state is one in flux. (Laughs) that’s an easy comment because there’s always change going on. I would say that in general, we have a planet with a great maldistribution of burning. There seems to be too much burning in some places, not enough burning in others. In general, much of the developing world that is still relying on living biomass for its fuel sources, there tends to be too much burning. Fire is very much an interactive technology. It’s fire interacting with other things to produce nasty consequences. In the developed world, interestingly enough, there’s probably not enough. And we’re suffering all kinds of ecological ills because fire, which had been a part of many systems, particularly in nature preserves, and so forth, has been removed, removed rather abruptly, its pattern changed, so now when fires appear they appear in a very different form than they had before.

ES:

SP: Well, fire is very much what I would call a pyhric double of ourselves. It really takes on our character. I mean it has an existence quite apart from people. The way it appears on the planet now: where it appears, the dynamic of how it functions, and so forth, so deeply involved with people for so long, that in some way’s it’s an extension of ourselves. And so it has all of that complicating factor as well. You can look at the kinds of fire regimes that people shape, different societies shape. You can look at their different architecture, literature, political institution, because that reflects the values and choices those people make. How do they see themselves, how do they see themselves in relation to the larger world, those kind of issues. And so in a sense, fire has become as morally complicated as ourselves. It’s been brought into our own moral universe. Because we are so dependent on it, we have used it for so long, and the way it appears in the world reflects our own values and choices. So it isn’t simply bad intrinsically, it’s like ourselves. It’s very much like ourselves.

ES:

SP: Fire regime is a wonderfully useful but slippery concept. It could mean different things to different people. Basically, it describes the pattern of fire that appears on the land. So that it may refer to the typical frequency of the fire, the seasonal timing of the fire, the intensity of the fire, the geographic size of the fires. In other words, fire appears in particular ways. And if you look at the ways in which it appears, then you can begin describing a fire regime in the same way you can think of a precipitation regime. What is the pattern of rainfall in a particular place? Does it all come with summer thunderstorms? Does it come with winter rain? Is it a Mediterranean climate? And individual fires appear within a regime much like individual storms do within a climate. So in that respect it becomes very slippery. But on the other hand it’s clear that fire does organize itself in different ways and into certain kinds of patterns. And in the regime, fire regime is a very useful way to describe that fact.

ES:

SP: Well, lots of things surprise me. I guess one of the things is the ubiquity of fire – that is, the extant in which it is embedded in our experience, our human experience for so long. Even in industrial and urban societies where we hardly see fire at all anymore. In fact, open burning of almost any kind except the most simple, ceremonial candles on a birthday cake or equivalent are banned, nonetheless how fundamental the catalyst, how basic to our ecological identity, our species identity. And the rediscovery of that relationship, that pact we made is in a sense a faustian bargain we made very early on that we acquired power as a species, special standing as a species by our capacity to control fire. And I’m sure that it’s a power that we’ll never allow willingly for any other species to posses. And the constant rediscovery of how fundamental that is for us, I guess is the biggest surprise.

ES:

SP: Well, I don’t think it was giving up, it was taking on a responsibility. In a sense we agreed – I’m anthropomorphizing here – to see that fire got put on the landscape in a proper way. The ability to control fire gave us an enormous ecological power. We acquired that power, and with it came the responsibility to use it sensibly. There’s plenty of evidence from our history that we are not. And we still aren’t. I guess not using it as simply a form of vandalism, not simply using it as a form of ecological warfare. But, recalling that much of the biota around us is dependent on fire occurring in certain ways, not occurring in other ways, and that that is our particular task. And that doesn’t mean we burn everything in sight, it doesn’t mean we try to eliminate fire wherever we see it. It means we try to make the best call we can. And it’s very hard to know what that best call is. But that in a sense is the task we’ve been given. And I guess it’s just the recognition that even though we don’t see the fire anymore, we’ve got it buried in internal combustion engines, and we’ve buried in power plants and dynamos, and we see it second or third hand. Or we only experience personally in virtual form by television or whatever. But that reponsibity is still ours. And we need to think of ourselves as fire creatures. We need to admit to ourselves that we are still the keepers of the planetary flame, and begin thinking more sensibly about how to use that power more properly.

ES: What motivates you to study fire?

SP: Well, this is very simple. I’ve described myself as a pyromantic. That’s not a pyromaiac. I had no particular fascination as a child with fire, let’s be clear about that. What happened, was that right after I graduated from high school I got a job at Grand Canyon National Park. They had an opening the day I showed up on the fire crew, on the North Rim. They asked if I wanted it and I took it, and then spent 15 summer on the fire crew there. And that was, really, the origin of my interest in fires. We lived around fire, our lives were organized by it, it’s possibility of occurring or making it happen. I really had too lives, went to school, graduate school and did nothing with fire, academically. But then after I got my doctorate I realized that I was really interested in fire, and I ought to apply the techniques I’ve been trained and the scholarship I’ve been educated in, apply that to the subject of fire, that would be a unique synthesis, so I’ve continued to do that. I’ve done some other things, too, but the fire thing has been my mission.

ES:

SP: I think it came up slowly. You know, in retrospect, and from the outside, you may very well shake your head and say: how dense is this guy? why can’t he get it? this is obviously what he should be doing. I have lived two completely separate lives. I mean, I would go to school and do my academic stuff, and then I’d put all that away, put on my boots, pick up the shovel and go fight fire. Then, at the end of the season put all that away and go back to school. And they were two completely separate worlds. So it wasn’t until that pattern finally broke – that is to say I had graduated, I had no academic job, not clear what I’m going to do with the rest of my life, I still have some active years on the North Rim and am keen to take it. And at that point, breaking that cycle, that pattern, that habit forced me to reexamine what I wanted to do and I realized that fire would be a really great subject to treat in the way I’ve been trained. And so at that point I really began a process of retooling and a way of merging what had been two very separate lives.