A Forest that puts out fires

Smokey the bear, you’re fired!

By Bryan Zepp Jamieson

7/24/03

http://www.zeppscommentaries.com/Science&Environment/fire.htm

I glanced at the thermometer on my front porch as I got home from work and winced. Ninety-four isn’t a record for us – it hit 99 last year – but it’s plenty damned hot. Out back, where there’s a wading pool for the dogs and plenty of shade, it was only 90. (Last year, when it hit 120 in nearby Redding, one woman called in to her local radio station to report that it was 118 at her place. "But," she chirped cheerfully, "with the wind chill factor, it’s only 115!")

A sharp edge divided the sky, deep blue above, leaden grey to the north east. Thunderstorms would be raking through the high spruce and red fir forests in the rain shadow of Shasta tonight. A brownish tinge to the clouds suggested there were already fires burning.

Not for the first time, or the hundredth, I felt gratitude that the Forest Service and private landowners had jointly built a firebreak around the town last summer. No place in the western forests is 100% safe from fire, but our odds are much better than they were a year ago should a big fire come roaring through. And one will, eventually. That’s certain. It’s one thing to have a fire-resistant roof and clear the brush around the house, but when you have a 150 foot wall of flame 75 yards from your home, it often isn’t enough.

Anyone who lives in the forests will tell you that the number one topic for debate is almost always going to be that of forest management. City folks might be surprised to learn that everyone agrees that some sort of forest management is needed. With rare exceptions, the forests out here are almost entirely artificial constructs, usually from a confluence of logging, development, fire fighting and roads. It’s the exact nature of how those forests should be managed that stirs up all the dust.

We exist, for the most part, in forests where there is simultaneously a lack of merchantable trees, and too much growth. If I had to describe a typical stand around here, I would say it was about 80% ponderosa pine with equal minorities of white fir and cedar, with a closed canopy of about 15-20%, and a lot of undergrowth – manzanita and chaparral, mostly. There is far too much "dog hair" – that’s groves of saplings, hundreds of little trees each an inch or less from its neighbor.

I would be describing a forest that would burn like a mad bastard when the fire comes. And it isn’t unique to my area by any means – the entire west is in similar straits. Except straits generally have water. We don’t even have that.

There are several elements governing how much damage a fire will do in a forest. Most can be predicted using nothing more than common sense. Small trees burn more easily than big trees, especially in pine forest where the lowest branches on big trees might be fifty or a hundred feet up. The more underbrush, the bigger the flames and the faster they spread. Small trees let in more sunlight than big trees, hence more underbrush. And the closer to one another trees are, the easier it is for a fire to spread amongst them. Forestry majors from Cal Berkeley usually know all this before they’ve cracked their first book.

Very little of the forest resembles the forests that covered the west 300 years ago. It isn’t just the effects of logging that caused this. True, there is a big deficit in mature trees, but the days of rape and run logging are long past. The average individual tree age of a forest might be much less than it was in 1700, but it’s probably more than it was in 1950.

The biggest villain of the piece is Smokey the Bear. Ever since the fiery summer of 1911, when the authorities decided that having three million acres go up in flames was unacceptable, there has been vigorous fire suppression. Unfortunately, forests actually NEED fire – in a "natural" western pine forest, a fire might come through every ten years or so, and clear out the underbrush and saplings, but burn cool enough to leave the nutrient- and water-holding duff intact, along, of course, with the mature trees. Sorry, Bambi’s mom. But try and look on the bright side: a more open forest means more foliage for Bambi to munch on. Easier to spot predators, too.

That so-called natural forest would vary enormously, just as a crowd of average people would, but it would in the main resemble parkland more than the dense, dark impenetrable thickets that you see so frequently in forests that have been protected for the past 100 years. The natural forest would feature a fair number of clearings, and the stands would feature trees of a generally similar age, well spaced apart – perhaps 75 or 150 feet from tree to tree. Remember that when John Muir rhapsodized about the pristine forests of the 19^th century Sierra, he did so from horseback. The forests were that open.

There’s no question that vast tracts of forest are overgrown. Every year millions of acres burn, some so hot and fierce that the land is damaged for decades. Hundreds of homes burn, and last year we lost over a dozen firefighters. Forest fires cost hundreds of millions of dollars just in containment expenses.

With all this as a backdrop to my quotidian existence, it’s no surprise that I sat up and paid attention to a New York Times article about a wild fire hitting an experimental forest which featured a variety of forest management techniques. The article, written by James Gorman, was entitled "How a Forest Stopped a Fire in Its Tracks" ( The so-called "Cone Fire" had burned into the Blacks Mountain Experimental Forest, an area the Forest Service had been using to study forest management techniques for almost seventy years. The fire hit a line of 12 250 acre areas that had been subjected to differing approaches in forest management. A situation yielding such empirically pure results hadn’t occurred before.

Best of all, the story was local to us, just up the road in Lassen National Park, which is only about 80 miles away and features terrain and forest quite similar to ours. By the time I was halfway through the article, I stopped and forwarded a copy to a friend who is the chief organizer of the local Fire Safe Council, a safety expert and arborist who is determined that Mt. Shasta will not be the next Oakland Hills or Painted Cave fire.

The article is important to everyone in the west because the happy coincidence of a wild fire roaring into zones featuring a variety of forest management fire suppression techniques gave the first reliable empirical data as to what works best to slow down and even stop a fire, while maintaining a healthy and natural forest.

For a nice change, the experts weren’t amazed by the results. Forest that had been selectively logged – that is, where every other tree or every third tree had been removed on the basis of position and/or size and age – slowed the course of the fire.

But where the results were most spectacular was where the forest had been selectively logged, and then prescribed burns applied to remove much of the underbrush. (They used to call them controlled burns, but got tired of hearing jokes about controlled burns that destroyed small towns, so now they call them "prescribed burns," possibly in the hopes that they can blame the medical profession when one gets loose and eats Hayfork).

The pictures accompanying the story are spectacular. The forest areas where the management techniques had been applied were rectangular, and there is this unbelievably sharp, straight line where the fire just simply . . . stopped.

One slight surprise was that stands of medium sized trees did a better job of stopping the fire than stands of big trees. But the difference wasn’t that great, and was easily explained: the forests of big trees had more "duff" – needles, branches, other debris – on the forest floor, and the fire was able to penetrate a small ways in, but greatly reduced and easy to put out. The trees, as expected, did fine.

Some logging companies won’t be thrilled by this news. A timber industry executive, not surprisingly, would like to learn that the best way to manage a forest would involve him being paid to take out everything with a trunk more than a foot in diameter while leaving all the rest for someone else to worry about.

But they won’t be disappointed or even alarmed by this news, either. It is, after all, just common sense, and no timber industry type, no matter how rapacious he might be, wants to see the forests burn to black glass.

That the results showed that managed forests slowed and even stopped fire was no surprise at all. Most forest management is common sense backed with enough science to measure what you are doing.

But that the results most people thought would work the best, and produce the best forests, worked so well was a happy surprise to nearly everyone.

Now we have a solid example of what works. And we can start working to save our forests as well as preserving them.