Tuesday, March 23, 2010

The Smell of Biodiversity

After the rain and snow event this weekend, I didn't think I'd see a single flame this week. Leave it to the fast drying nature of curled post oak leaves (which maximizes surface area), plummeting relative humidities (down to 22% today), and a long sunny day on Monday to bring that welcome smell of rich-woods-on-fire to my hair again.

Fuel moistures at the ground level were still pretty high, which meant that the 550 acres we burned saw an event best characterized as a "light surface fire" --one that burned off last year's leaf litter, but left some wet leaves in tact on the woodland floor. Historically, these were common on the landscape, sometimes occurring annually in the more flammable reaches of the Ozark Highlands. But in the event of an old fashioned woodland restoration project, a little light surface fire like today's won't cut mustard.

Today I was at the end of a crew with a drip torch, filling in where the fire stopped and stripping out hollows and hillsides in the middle of a beautifully restored woodland. Only three years ago we burned this same area with the wind fighting us all day in an event where I experienced my very first slipped disc after slipping on a boulder. I kept up with fires for the rest of the season, but the pain was....well noted on each event. Nevertheless, the April fire three years ago here crawled slowly and resolutely across the post oak/blackjack oak flatwoods, and in the end burned the whole area to mineral soil. Wind was our friend today, fuel moistures were still a little high, but I was on the road to Columbia by 4:30 because it burned out so quickly.

If I haven't reiterated enough the importance of diversity in a fire regime, I'll write it again: don't burn the same tract of woodlands every three years on the same date, with the same humidities, with the same fuel moistures. Diversify the fire regime to better mimic the natural processes that gave rise to our biodiverse systems to begin with. It's downright destructive to send hot April fires through the same tract of woods every few years. And conversely, it's worthless for restoration goals to burn when your fuels are wet, humidities never dip lower than 51%, wind speeds of 5 mph, and temperatures below freezing. Unfortunately, some in the field burn this way, and because of this, they will never have the beautiful, diverse, dynamic landscape that I burned today.

8 comments:

James C. Trager said...

We've already corresponded on other aspects of my thinking on late burns, but I would add this: The early spring flora in the woods is well along in the development of its flower buds, and most species will not regrow them if the buds are destroyed by fire. Of course, the plants, being perennial, will carry on, but they won't have the sexual-reproductive advantage of dropping their seeds on bare ground, as they would have if the sites had been burned earlier, before said flora sent up its flower primordia.

Allison Vaughn said...

James, why do you do this to me? Don't you know how exhausting it is to rehash the "sacrifice the few for the longevity of the system" argument? I've had to deal with so much crap today, including illegal widespread timber harvest at my favorite tract of woods--every 30-28DBH white oak cut down over an entire valley--that I just can't engage. I'm not destroying the natural world by setting it on fire.

Travis said...

ok, i'm stepping in.
obviously James doesn't think you're destroying the natural world. i have also mentioned how much i love late spring fires not only because of their destructive abilities, but because i hate ants. ha.
really though, late fire is a tool that sits in the belt of the restorationist and, much like the jar of moonshine on my shelf, it should be broken out very sparingly. multiple years in a row will begin to damage the spring ephems and even though they might seem like "the few" they are very important and shouldn't be overlooked just because they are little or only around for a short time. (the same could be said of people)
sorry, but talk of burning up spring ephems makes me put my fins out. i mean, those flowers pull us out of winter depression and the short window that they bloom is the only nearly allergen free time i have in the woods before all the catkin danglers make me a human snot machine.
hey look, moonshine.....

James C. Trager said...

Sorry, I don't mean to harass, and least of all do I want you to take it personally. I agree, you're not destroying the natural world with fire. It's just I keep thinking about these many details and how they might add up in a world where species are winkng out of existence, at least in small remnants, which I admit is not what you are dealing with. Your last couple of sentences about switching up the management regimen are really important, and I'm pleased you mentioned them.

The timber cut -- How the heck do these poachers get in unnoticed?! TNC had huge walnuts poached out of Marmaton Bottoms some years ago, and we all were aghast and saddened.

Allison Vaughn said...

Anything smaller than a 40 acre tract is an operational burn in my world, and I don't do operational burns. I deal in landscapes, resilient, healthy landscapes that have adapted to fire over a million years.

Allison Vaughn said...

You're funny travis. You know, I know of a certain group of people who only burn during extreme fire conditions in April, year after year. I don't work with those people and never will. Hey, I see wine.

James C. Trager said...

All right, seems like we're really all pretty much on the same page. I just want for everyone in this field, and those who follow our activities, to be as fully mindful of what we do as possible.

Travis, I am loath to disappoint you, but late fire is much harder on ticks than on ants, so you might have to miss the beloved arachnids and put up with the annoyance of these little social insects, anyway.

And I see something dry-hopped.

A.J. said...

It is such a sweet aroma indeed!