Historical Forest Development Pathways
April 4th, 2007
Fifteen thousand years ago the planet was gripped in an Ice Age stadial. Continental ice sheets and tundra covered much of North America. The forests of today did not exist at that time, except in isolated refugia in southern and coastal areas. Most of the acres covered by forest today were not forests 15,000 years ago.
Then the Holocene began, the planet warmed, and the ice retreated. Over time, forests developed where they did not exist before (at least not for the previous 120,000 years). The progression of vegetation change (from ice/tundra to forest) that actually occurred is called the historical forest development pathway.
Not all forests are alike. Many different species mixes and types of forests exist across North America today. Obviously, there have been many different forest development pathways. No one pathway happened everywhere, or else all forests would look the same.
Forests across North America have certain similarities, however. It appears that all or almost all tracts of forests of every type have experienced quite a bit of fire in the Holocene (remember, before the Holocene the ice and tundra did not burn, and the forests of today did not exist). We also know from common experience that fire can kill trees and sometimes all the trees, regardless of forest type. Putting two and two together, it is widely concluded that fire was an important element in the historical forest development pathways.
That is, fire has been an important disturbance agent, and forest development is disturbance-related. Forests change when disturbed, especially when fire is the agent.
A crude, early theory of historical forest development was that today’s forests consist of even-aged stands where the trees seeded in at roughly the same time following a “stand replacement” fire. This theory was at first widely assumed to be true for almost all forests. It was certainly true for younger tracts of forest which had arisen in even-age fashion following well-documented stand replacement fires.
As more and more forests were investigated for actual age distribution, a gaping hole in the early theory developed. The anomaly is that many forests, particularly older, untouched forests, are not even-aged. Instead, many (if not most) older forests are distinctly multi-cohort. That is, forests often have two or more widely divergent age classes of trees.
This fact tends to disprove the “stand replacement fire” theory, at least in regards to older forests. Their development pathways must have been different than that.
It is now widely concluded that many (if not most) North American forests were at one time (120 to 500 years ago) open and park-like with widely spaced, large, old trees, and that forests were conditioned to be that way by frequent, non-stand-replacing fires. The new theory holds that historical frequent fires were light and low-burning, and that those fires did not kill the bigger trees.
That is, the actual historical development pathways for many (if not most) of our forests involved frequent light fires, not stand-replacing fire.
Nowhere is this more apparent than in the Biscuit Burn and in other burns of the last few decades in southwest Oregon. Typically the forests that have been burning were strongly multi-cohort with older cohort trees of 150 to 600 years of age. Also typically, the vegetation that arises after the fires is sclerophyllous brush with a few, even-aged conifers.
It is clear that the new forests will be nothing like the old forests. In fact, it is probable that the new forests will burn again after 15 to 50 years of new fuel development. We know from reburned areas such as the Silver Burn (1987) within the Biscuit Burn (2002) that the new forest is highly flammable and prone to total conifer mortality. After reburns no conifer seed sources are left, and the new “forest” becomes a permanent shrubfield.
The conversion of forest to brush by fire has also been recognized in Arizona pine forests. Barbara A. Strom and Peter Z. Fulé of NAU recently did a study of post-fire forests, and their report was published last month in the International Journal of Wildland Fire. Here is the abstract:
Pre-wildfire fuel treatments affect long-term ponderosa pine forest dynamics
Barbara A. Strom and Peter Z. Fulé, School of Forestry and Ecological Restoration Institute, Northern Arizona University, PO Box 15018, Flagstaff, AZ 86011, USA.
Abstract: The 2002 Rodeo–Chediski fire, the largest wildfire in south-western USA history, burned over treated stands and adjacent untreated stands in the Apache–Sitgreaves National Forest, setting the stage for a natural experiment testing the effectiveness of fuel reduction treatments under conditions of extraordinary fire severity. In seven pairs of treated–untreated study sites measured 2 years after the fire, thinning was strongly associated with reduced burn severity. Treated areas had more live trees, greater survival, and reduced fire intensity as indicated by crown base height and bole char. Ponderosa pine regeneration was patchy but more dense in treated areas. We assessed decade- to century-long effects of the pre-wildfire fuel treatments using the Forest Vegetation Simulator (FVS). Differences between treated and untreated areas were projected to persist for several decades after the fire in terms of stand structure characteristics and for at least 100 years in terms of species composition, with ponderosa pine making up ~60% of basal area in treated areas but only 35% in untreated areas. Future ecosystem development may take the trajectory of recovery to a ponderosa pine/Gambel oak forest or of a shift to an alternative stable state such as an oak-dominated shrubfield, with untreated areas more apt to undergo a shift to a shrubfield state. Current management decisions about fuel treatments have multi-century legacies.
Keywords: Arizona, Forest Vegetation Simulator, fuel reduction Rodeo–Chediski fire.
International Journal of Wildland Fire 16(1) 128–138. Published 20 February 2007
To summarize, the authors found that after a modern severe fire, untreated pine forests are apt to shift to a stable shrubfield state. That is, modern stand replacment fires do not give rise to forests; they give rise to permanent tick brush.
The historical forest development pathways were different. They must have been different because they gave rise to open, park-like forests with old trees, not permanent brushfields. The big difference: historical pathways had frequent light fires, not devastating stand replacement fires.
Furthermore, frequent, regular fire is an artifact of human presence and human ignition. Fire has been a non-natural, human-controlled disturbance in the forests of North America for 10,000 years or more. No doubt lightning fires occurred, but they occurred in landscapes “pre-programmed” by people. Lightning fires in open, grassy forests quickly dropped to the ground and acted just like people-set fires. To deny this human impact is to completely misread the actual, evidence-backed, historic forest development pathways throughout North America.
Recently (this AM) the newspaper reported that yet another study has been made of conifers seedlings discovered growing in the brush on devastated burns of southwest Oregon. Nothing new about that. It is well-known that some conifers will germinate and grow following stand replacement fires.
However, the newspaper report (and the study apparently, we haven’t read it yet) fails to note that the new forest is quite different than the old forest, and that the new forest is well on its way to becoming a permanent brushfield.
The problem is a lack of understanding about the actual, historical forest development pathways. Understanding is crucial because the historical pathways must be replicated if we are to save our heritage forests from extinction. If we allow Mother Nature to have Her way, our forests are condemned, and our legacy to our grandchildren will be brushfields, not forests.
April 5th, 2007 at 2:54 pm
Hi! Good post, with good info. It is hard to find accurate forest facts, especially in the whole fire-what-to-do-about-what’s-left-in-the-ashes debate(meanwhile, nature goes on doing its own thing, and is that even something we’d be satisfied with in our world-in-our-image mindset?).
Just to get my understanding right, are you saying the brushfields would not be recolonized by trees(over the next 1000 years)? And who are we to say how the landscape should look like–I agree the parkland model is probably the most natural and “sustainable”. (I’m not commenting on you, just everyone who thinks they know everything there is to know about how nature should conduct herself). I think it takes a lot of research(historical and on the ground) with open eyes and heart, and no agenda.
I’ve been learning about the Tillamook Burn, both reading and just poking around when we go camp there. It’s a fascinating story, and the results are amazing. I’m surprized it hasn’t gotten more press as a success story. I’m sure it has its pros AND cons, but overall, it’s miraculous how that forest has come back after 75 years. At least I think so.
Thanks!
April 5th, 2007 at 3:53 pm
Celeste,
Thank you for the nice comments. To clarify about brushfields:
Following a devastating fire, brush will sprout immediately because their root systems are still alive. The conifers do not sprout back, but conifer seed in the soil will germinate and seedlings will take root.
But the brush itself is very flammable. So are small conifer trees. Before too many years have passed, lightning will strike again. That fire will kill all the small conifers and burn the brush back to ground level. Then the brush will sprout again, this time with few or no conifers.
And again, after a few years, the whole landscape will be flammable again, and in the absence of fire suppression, will burn again. Thus a permanent brushfield, or stable shrubfield is created out of old-growth forest.
The Tillamook Burn is a good example of this. The first fire resulted in brush plus conifer seedlings. The second fire left pure brush. The third fire was ridiculous, and people put in roads and planted conifers because otherwise the Burn would have been permanent incendiary brush. The fourth fire was not as bad as the others because of improved fire suppression on the improved road system.
The Biscuit Fire was the second in the series, following the Silver Fire. They were 15 years apart. We can assume therefore that the Biscuit Burn will be flammable again in 15 years (2017).
The Biscuit Burn is slated for Let It Burn fires for the indeterminate future. No one is planning to fight brush fires out there. The USFS didn’t fight the fire when it was in old-growth preserves. Why would they fight it in brush?
Part of the Silver Burn was salvaged logged and planted, and part was left untreated. It didn’t matter to the Biscuit Fire; both areas were devastated. Once the first stand replacement fire occurs, the vegetation is changed forever.
Stand replacement fires in old-growth (multi-cohort) forests eliminate the older cohort and forever prevent any trees from getting that old again. Unless there is effective fire suppression for 150+ years, which is doubtful even if our fire suppression community wasn’t under attack at present, which it is.
The best option is to restore a fire-safe landscape before the stand replacement fire. By fire-safe I mean able to accept frequent, light fires that don’t kill the trees.
Once all the older trees are dead, frequent fires make it tough for any seedlings to survive. It is probable that the open, park-like, conifer savannas arose from slow tree invasion of frequent-fire grasslands and fern brakes induced by anthropogenic burning, not the invasion of grass or fern prairies into thick forests. And that process probably took a thousand years or more in many places, historically.
Nowhere is that process occuring today in nature. The only places where savannas are developing or being maintained is where people frequently burn the landscape.
Agenda-driven science is indeed problematic. It is especially so in this case, where the agenda is the catastrophic incineration and extinction of our most treasured forests.
April 7th, 2007 at 12:41 pm
Mike,
Question: in a brush field, can you burn one annually and actually take out the brush by annual spring burning. The premise is that you keep taking the stored energy of the roots out by spring burning, when all the root stored energy has been used to promote new growth, and nothing yet has been invested in the root system. And if that works (I use a herbicide to do the same thing….you know us farmers really can’t burn anymore), could you really get a good control on brush, and perhaps get into a conifer rebuilding program???
My 40 years in this business of trees and forest, I know we planted with full knowledge we would thin. Maybe several times. Accordingly, more trees were planted than necessary. So unthinned, the new forests, natural or planted, are no different than aforesting by chance in a wilderness. Even before Donato, we knew there would be natural infill. The issue was to make damned sure we met the public expectation of reforestation, and the private capital expectation of a future crop. It is now a succession of too many trees, nutrient and water stress, insect attact, and fire making the land “BEAUTIFULLY BLACK, BURNED, AND NO THREAT TO WEYERHAEUSER’S FUTURE PROFIT STREAM.”
I will never let go of the fact that long term, long rotation, publicly grown trees produced logs that Weyco could not provide, and products that Weyco had to compete against with their small log, second and third growth forest products that were engineered and chemically bonded, stitched, glued, jointed, all to build a house or commercial property without using a large log product. Weyco could not gain needed market share as long as vast public forests produced large logs, even in second growth, and competitive, agressive, dynamic small mills used them too efficiently compete in the market place. Get rid of the public timber, and Weyco is whole.
Mark Rey, a former agent from their megapulp lobby group, got the job done by investing the Bush administration in poor public policy changes, heavy handed administrative rules, and subversion of public timber use, including aid to over 800 counties formerly sharing in timber revenue. His last two years being the civilian in charge of the PissFir Willies and Wilmas are devoted to closing the door to public land logging by burning down the forests. So clever! So conservative! What is good for General Bullmoose is good for America!!!!
My years continued to add up, and my disgust with government grows at an even faster rate!!! You would think I could have cut it at culmination of mean annual increment. Only I ain’t got there yet!!!!
April 7th, 2007 at 2:16 pm
john,
Answer: yes, annual burning will severely impact the brush and supplant it with grasses. I have gotten better kill on poison oak and blackberry by repeat burning than herbicide, and that has been somewhat surprising to me. One burn doesn’t do it, but Burn #2 or #3 really knocks them out.
Conifer saplings survive grass fires much more readily than they survive brush fires. And that, I hypothesize, was the historical development pathway of conifer savannas. Repeated burning led to prairie grasses, and thence to open forests.
Regarding the Monopoly. The irony is that Weyco is right now logging the hell out of government forests, but they are BC Crown Lands, not USA public forests. Weyco won’t touch a USFS log. They purchase zero fire salvage logs, and don’t buy USFS timber sales either, to my knowledge. The BC logs are dirt cheap in comparison, and so is the lumber sawn from them. Weyco has been dumping BC lumber on the US market and bankrupting US producers in the process.
And people wonder why all the lumber comes from Canada.
I used to think Weyco was behind the conspiracy to burn USA forests to smithereens, but my thinking has changed. Now I think it’s a leftwing plot perped by radical anti-American arsonist/terrorists, and merely funded by Weyco. However, I could be wrong on both counts (I haven’t been going to the meetings).
April 8th, 2007 at 2:52 pm
Mike…I don’t think Weyco can buy a USFS sale. I think the SBA set aside is still in effect. I did see Hampton, no longer a “small business” by SBA standards, bought a set aside sale that no small business bid on, when it was reoffered to all buyers.
I also think that USFS timber can’t get a “green” label. The “green’” label requirements were rigged so that USFS timber does not qualify. Like you can’t catch an organic salmon in the ocean. No controls to ensure purity of food. So the marketers sell “wild” salmon. The Greens have a way about them. And as True Believers, we should expect they would be zealots.
My kid is a logger, and certified to be one. You have to be a certified logger to work for any outfit whose lumber ends up at HomeDepot or Lowes. If you smoke a cigarette on “Weyco” land, you are banished. Tramped. Don’t come back. A log truck driver cannot smoke in his own truck. Not on Weyco ground. And it is the flame orange safety vest, hard hat, safety glasses, when you get out of the truck for any reason. It is about control. Mastery. The last word. Big Daddy. General Bullmoose. The bs story about taking Willamette Industries because they wanted their better culture was just that. All the WI folks have ended up Weyco clones. Automatons. Mindless lockstep Masters.
Burning the forests is mindless KoolAid drinking. The PissFir Willies just are the most rudderless ship in the sea. They don’t know sour owl poop from apple butter. They don’t know who they are, what they are to do, why they should do it or not. Clueless. Full of discipline specific “ologists” of every stripe, and no leaders, Jerked around by political hacks from the Bush Ag dept., and D.C. based bean counters, with no rudder and no rudder builders, or spare rudders in the line of succession, the USFS is blown this way and that by the political winds of the Clinton storm of more than a decade ago, a storm that keeps on blowing. It is sort of fun to watch, because you can’t figure out what kind of outrageous crap is about to spill from the Forester’s fountain of diversity, public imput, and contrived science. No matter. Nothing good is going to come from it all, which is sad, but maybe the hunting will get a little better with some sunlight hitting the ground.
April 8th, 2007 at 4:26 pm
The USFS lost their core values, and that has crippled them. But I intend to reinstruct them, even if I have to drag them kicking and screaming up the learning curve.
john–they are just people, like you and me. They are weak and sick. We can help them to get better. It’s doable. Don’t give up.
April 8th, 2007 at 6:11 pm
And john, add two plus two.
They know that they are sick, and rudderless, and without a clue.
And they know that we know it, too.
That’s why they took down the Wildland Fire Leadership Council minutes. It was in response to the April 3rd SOS Forests post Cranking Up the Whoofoo Propaganda Machine (here).
We accused them of breaking the law, and they knew they were, and they knew they had gotten caught. Their immmediate response was to cover up and stonewall. But they also know that strategy won’t work for long, if at all.
We are effecting the debate on wildland fire use that never happened. We set the debate agenda now, and we select the participants. You may think that statement arrogant and laughable, but the facts remain: the DC power elite in the USFS, BLM, NPS, the USDA, and the USDOI are reacting in spasmodic and paranoid fashion to little bitty SOS Forests.
The top brass in the USFS are reading your letters, john, and it’s giving them the galloping fantods. Please keep up the good work.
April 8th, 2007 at 9:56 pm
And by the way, john, the folks behind Black, Burned, Dead Forests Are Beautiful are as anti-hunting as they are anti-forests. Across the West, game animals such as mule deer and elk and being systematically decimated by disease and introduced predators as part of a larger plan to eliminate hunting.
The wackos’ goal is to eliminate humanity from the landscape. That means no hunting by humans, and if they have to drive game species to extinction to do it, they will. It’s the same reason they burn forests: dehumanization. You know that they don’t give a rat about spotted owls; they’re on a mad dash to incinerate owl forests. Do you really think they give a rat about deer? Or rats either, for that matter?
If I had the time, I could do two or three more blogs on wildlife issues alone. The daily flood of reports of Bureaucrats Gone Wild in the wildlife vein swamps my email. Suffice it to say: chain saws and guns are taboo in the Brave New Age World.