European Forests Also Need Control Burns

…but are not getting them. European forests have grown up in thick stands of saplings, just like most American forests. In North America, the Natives kept the forest undergrowth cleared away, which benefited agriculture and hunting, by the controlled use of fire, as I explain in chapter 2 of my recent book Forgotten Landscapes. When European diseases and conquest killed off ninety percent of Native populations in America, the forests shifted from bountiful productivity to being “a forest of sticks” choked by undergrowth.  Native fires were an essential part of what a “natural” forest should be like in North America.

It appears to me that the same is true in Europe. It is likely that the tribal peoples of Europe, before (and after?) Roman conquest, burned their forests just as Native Americans did theirs. The forest preserves we see in America, and in Europe, today are not “natural” but have resulted from fire suppression in recent centuries. This would be true even of the last “virgin forest” in Europe,  Białowieża in Poland.

I explored one of the last fragments of pre-industrial Rhineland forest in France earlier this summer. It is (what passes in Europe for) an extensive forest southeast of Strasbourg. I hiked around on just a portion of its extensive system of trails. Beech trees (Fagus sylvatica) dominated the canopy and its seedlings were abundant on the forest floor. Maples (Acer pseudoplatanus) dominated the forest floor and had some canopy trees, along with two species of linden (Tilia cordata and T. platyphyllos). There were a lot of shrubs, especially the field maple (Acer campestre), dogwood (Cornus mas), hazelnut (Corylus avellana), and hawthorn (Crataegus monogyna).

This forest had been undisturbed for a long time—the beeches were large and tall. But it was not that long ago, perhaps a century and a half, when the forest had been cut down. In a desperate but successful attempt to control the resulting soil erosion, the French government planted conifers (in the lowlands, Norway spruce, and on the hillsides Douglas fir from America) which persist in a few places, remnants of once successful forestry but now ceding their dominance to hardwoods.

It was a peaceful and wonderful place to hike. But it was not natural. In my book I wrote about Native inhabitants being an essential part of the “natural” landscape in America. And it appears that the same is true in Europe. I suspect this is a general pattern. Sam Goldwyn is said to have quipped that wilderness is “where the hand of man has never set foot.” But I think this may not be true not only in America but anywhere else. Humans have always been, ever since we mastered fire, an important factor in the operation of entire landscapes all over the world.

The only alternative to small, frequent fires is large, perhaps equally frequent fires. This is what is happening in America, where the lack of control burns has allowed huge forest fires to get started especially in the west. But the same is true where I now live in France. With increasing frequency, the forests of southern France burn in the hot, dry summers. With global climate change, the forests where I now live in northern France will also burn more frequently. The problem will take care of itself, though not in a way we would like.

Pyroterrorism?

This essay follows directly from a previous entry, based on Quand la Forêt Brûle: Penser La Novelle Catastrophe Écologique by Joëlle Zask (Premier Parallèle, 2019). (When the Forest Burns : Thinking about the New Ecological Catastrophe), about megafires. It made the point that, in the globally-warmed future, there will be no small fires, whether control burns or natural fires. They will all be big and destructive.

Toward the end of the book, the author mentioned a possibility that I had never considered, or even heard about: Pyroterrorism. That is, terrorists could start huge fires, believing that these fires would disrupt whatever little social cohesion that we have and leave us vulnerable to their other acts of terrorism. Apparently this idea has been published on foreign terrorist websites, to which I will not provide any connection.

It gets even worse. The terrorists do not even have to start the fires. They can wait for the fires to start in some other way, and then claim credit for them. They could say that, See, Allah is great, because He destroyed Paradise, California and surrounding areas in the 2018 Camp Fire, and He destroyed Maui in 2023. They would not have to say that their terrorist groups had started them, something of which most people would be skeptical.

But there are a couple of major reasons that pryoterrorism will either not occur soon or will have no great effect.

First, it is easy to start a forest fire. All it takes is a match. An arsonist can start a fire and leave so little evidence of his identity that no one would ever find him or even suspect that arson had occurred. Authorities estimate that there are thousands of such cases of criminal arson every year. But in order to prove that a fire began as an act of arson, much less to find the culprit, there has to be multiple simultaneous ignitions, and probably evidences of piling up brush and of gasoline. These are the things that would be necessary in order to give a fire a good chance of spreading. Even under hot, dry conditions, with lots of dry vegetation and strong wind, most fires will not become mega-fires under present conditions.

Second, terrorists have said online that a mega-fire would disrupt our society. But that is not what has happened. One of the few good things one can say about the modern world is that natural (or human-enhanced) disasters being people together rather than driving them apart. The California and Hawaii fires ignited an outpouring of humanitarian sentiment and relief. This has left the terrorists looking like the Grinch who was astonished to see the people of Whoville celebrating even after he had successfully stolen Christmas.

Neither foreign nor domestic terrorists would have much chance of success with pyroterrorism.

Enough mega-fires would cause such financial strain that we could have a major economic disaster, but it does not appear that pyroterrorism will destroy even the little bit of altruism that we have. So the good news is that there is one less thing to worry about.

The New World of Mega-fires

Mega-fires! Or, megafeux in French, as in the book Quand la Forêt Brûle: Penser La Novelle Catastrophe Écologique by Joëlle Zask (Premier Parallèle, 2019). (When the Forest Burns : Thinking about the New Ecological Catastrophe.)

Through much of my professional life, I have considered fires (in forests, prairies, and chaparrals) to be ecologically beneficial. Where to begin with the ecological benefits of fires? Fires clear away underbrush and release nutrients in the dead litter into the soil where new plants can grow back and use them. The sunlight can now reach the soil surface, warming it up earlier in the spring than would have been possible with a thick litter layer still in place. In many cases, the perennial plants that were present before the fire grow back, more vigorous than they were before. This is the case for hundreds of species of prairie plants, which maintain their thick sod of roots and underground stems. It is also true, as I have seen for the cross timbers forest of Oklahoma. As for the plants that grow back from seeds in the soil, the seeds germinate profusely, as I have seen Phacelia strictiflora do in cross-timbers forests after fires. So frequent are these fires that many plants have adapted to them even to the extent of requiring the fires to maintain their populations. My research has shown that Phacelia seeds require smoke chemicals in order to germinate; the same is true for hundreds of species around the world in fire-prone habitats such as chaparral. How can fire, which has so many ecological benefits, be bad?

Fire has long been a tool of habitat management. The whole landscape evolved with wildfires. Since the spread of western civilization, wildfires have decreased, mostly because people do not like to have their homes destroyed by fire. Ecological landscape managers have to set control burns to compensate for the decline in wildfires. This photo shows a control burn near Lake Texoma in Oklahoma in 1999.

In the absence of natural fires and control burns, dead biomass builds up under the trees and virtually assures that a fire will break out soon and be very big.

White landscape managers were not the first to use fire as a management tool. All over the world, native peoples have set fires to forests and fields to renew their growth. This was nowhere more true than with the Native peoples of North America, as I describe in my book Forgotten Landscapes.

But times are changing. In particular, global warming is changing the landscape. As Naomi Klein said in the title of her book about the economics and politics of global climate change, This Changes Everything. It has certainly changed the scientific way of thinking about fire.

Global climate change includes not only hotter temperatures but less rainfall and more wind in many areas, such as southern Europe during recent long, hot, dry, windy summers. This is not a prediction; it is something that has already happened in many parts of the world. Some of these forest fires have flames almost a hundred feet tall and that spread faster than anybody can run. The fires consume houses, including outdoor free-standing barbecue grills which are built to withstand fire: the grills simply melt.

Other human activities promote the spread of large fires. All around the world, not only in rainforests but even where I used to live in Oklahoma, native forests are cut down and replaced by tree plantations such as loblolly pine. Tree plantations, with breezy understories and with flammable, fast-growing trees, burn more readily than native forests.

The result is that, right when we need control burns more than ever, we do not dare to conduct them. There is a tremendous liability cost associated with a control burn that gets out of hand. If a private citizen loses so much as a shed to a government control burn, the land-owner will sue for lots of money. As global warming progresses, almost any control burn is guaranteed to escape and become a major fire.

A mega-fire, unlike most smaller fires, can and do sterilize the soil, so that there are no roots, stems, or seeds to grow back. The resulting moonscape will recover, but it might take many decades and suffer uncontrolled soil erosion in the meantime.

The time is coming, and in some places is already here, when there will be no such thing as a little control burn. There will be only mega-fires.

I have retired, so it is too late for me to tell my classes, forget everything I said about control burns.

A Look Back to Some Good Posts of the Past

For those of you who have only recently started reading this blog, I had some fantastic posts in 2012.

I took a long road trip from Oklahoma to California and back. One of the main purposes of this trip was to take photos and make videos to teach about evolution. I posted a series of “Evotour” essays, with photos. I saw some really interesting and thought-provoking things! The links are below:

• Eclipse of the Sun
• The Southwest Desert
• Parkfield Road, or, Skipping Across Crustal Plates. I visited the San Andreas Fault, where the Pacific Plate rubs up against the North American Plate. There is a bridge over it, labeled with signs, way out in the country!
• The Purisima Hills (with a remnant pine population and big lichens)
• The Transit of Venus, or, Guillame LeGentil Finally Gets Satisfaction. I saw the last Transit of Venus that any of us will ever see.
• Fire and Renewal in the California Mountains
• The Evolution of Christian Science. I visited a Christian Science church and tried to figure out how such a religion could ever have evolved.
• Feeling Small (in the presence of giant sequoias)
• Races of the Human Species: A Visit to Manzanar (a World War Two Japanese American internment camp)
• Among the Ancients (a visit to the oldest trees in the world)

I also posted a series about Religion and Science, The Vast Gulf. Science and religion differ markedly on such issues as:

• How to Find Things Out
• The Heavens (what are they?)
• Dust of the Ground
• You Are What You Eat
• Weather and Climate
• Continents
• Genetics
• Where Babies Come From
• Was the World Made for Man?
• The Future (this one was posted January 2013)

I also had a series of posts from the Oklahoma Evolution Workshop in October 2012. A stimulating experience, not to be forgotten!

I posted numerous free-standing essays, of which my best were:

Why Evolution Looks Like It Has an Overall Direction

Appealing to the Basest Instincts. This was about politicians, and it has suddenly become more relevant than ever!

Reality of Global Warming: The 2012 Phenology Conference.  Includes a part in which two scientists who consider global warming to be a gigantic problem were listed among the “3000 scientists who reject global warming.”

If you have time, take a look at these. I have left out essays which, however interesting, dealt with issues that were mainly relevant in 2012.

The Ecology of Disaster and Renewal

Nobody likes disaster. I strongly dislike even the smallest inconvenience. But they happen, and they have happened throughout the evolutionary history of life. And all organisms have inherited adaptations to cope with many of them, to a certain extent.

One such disaster (or, in ecological parlance, a disturbance) is fire. To all of us who watched Bambi, a forest fire is a disaster. But even in the Bambi movie, the dead forest had green grass growing after the fire. Disturbance is followed by renewal. This renewal occurs in stages (in ecological parlance, succession). There is no way to prevent all fires. Biomass burns. But most organisms have ways of dealing with fire—perhaps not as individuals, but at least as populations. Even alders, which grow out in the water, have to deal with it, because the flames can spread from the adjacent forest and burn their crowns.

A fire burned a large area of Cross Timbers forest near the Blue River in Johnson County, Oklahoma, in the summer of 2011. Despite its severe beauty, the fire was pretty grim for the plants and animals that experienced it.

There were burned turtle skeletons everywhere.

Yes, even the alders out in the middle of the river burned. But the next spring, in 2012, there was a luxurious growth of wildflowers and grasses, making use of the flush of nutrients released by the ashes of the fire. Many of the trees resprouted from the ground. By the summer of 2013, the growth was so exuberant that I could not even walk through it when doing field work with a visiting scholar from France.

But not all of the wildflowers, at least in 2012, were the same species that one normally finds in the spring. Two species in particular grew abundantly after the fire, but are rare the rest of the time. One is the mustard Selenia aurea.

The other is a member of the Hydrophyllaceae family, Phacelia strictiflora.

This wildflower is a relative of Phacelia grandiflora, which grows abundantly after chaparral fires in California. Now here is where it gets strange. It is no surprise that grasses and wildflowers grow abundantly after fires. What is strange is that a few species, such as Phacelia strictiflora, seldom grow except after large fires. That is, there is something about the fire that makes the seeds germinate. The flowers do not grow just because the ashes have released nutrients or because there is more sunlight as a result of the trees being burned. Many plant species that live in habitats with a fire cycle (such as the chaparral) require exposure to smoke chemicals in order to germinate. Phacelia grandiflora is one of them.

Oklahoma does not have any habitats with fire cycles. It therefore came as a surprise to us that the germination of the Oklahoma wildflower Phacelia strictiflora is greatly enhanced by exposure to smoke chemicals. The results of our research have just been published in the 2013 volume of the Oklahoma Native Plant Record. We demonstrated that very few Phacelia strictiflora seeds germinated—whether scarified or not; whether in light or in dark—unless exposed to a water suspension of smoke chemicals.

It was a fun experiment to do. How does one produce a smoke suspension, without having access to a budget for scientific equipment? You have probably already guessed the answer. Remember, this is Oklahoma. My student, Sonya Ross, who conducted the experiments, had access to a hookah pipe. We burned oak wood in the bowl and drew the smoke through the water. Usually hookah aficionados want the smoke, but we wanted the water, which after a few hours had turned amber and had a smoke scent.

This allowed me to produce a particularly interesting Darwin video. This was a low-budget experiment, but it yielded important results. This may be the first report of a plant species from a habitat that does not have a fire cycle but whose germination is so strongly enhanced by smoke. Many seeds germinate more upon exposure to smoke, but not this much.

There are a lot of interesting experiments just waiting to be done and which do not require a lot of equipment or a budget. Please check out the article. And I have to say, good work, Sonya.

Oh, and by the way, oak smoke is not very enjoyable, even after it has been through a hookah pipe.

Evotour, Part Six. Fire and Renewal in the California Mountains

Cuyamaca Rancho State Park in California used to have meadows surrounded by pines and black oaks. The pines and oaks extended partway up Stonewall Peak. But in 2003, a fire burned the entire area except some places around the meadow. Today, that meadow is the only place you can find pines and black oaks.

However, the chaparral shrubs have grown back profusely. I am accustomed to dry chaparral that consists mostly of dead sticks, but this chaparral was filled with fresh green stems, flowers, and fruits. Along with the profuse regrowth of manzanita, ceanothus, scrub oaks, and holly-leaved cherry, there were perennial wildflowers in full bloom: penstemon and yerba santa. The shrubs had grown over three meters tall and state park personnel, the few that remain after budget cuts, have to keep trimming them away from the trail. A few of the black oaks have resprouted, and a few pine seedlings have been replanted.

This is a theme I have presented before, but I enjoy being reminded of it when I see it again in the natural world. Ecological disturbances, such as fires, are disasters for the organisms killed by them, but act as a source of renewal for the ecosystem as a whole. Dead grass and wood are transformed into fertilizer that feeds the vigorous growth of new plants, either resprouts or seedlings. The chaparral in Cuyamaca, and the tallgrass prairie of the Midwest, depend on a fire cycle.

I do not doubt that my hike at Cuyamaca would have been prettier if the pines and black oaks had been intact, but I would not have seen the way organisms capitalize on natural disturbances as an opportunity for renewal.