The concept of fire rotation...

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Don
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The concept of fire rotation...

Post by Don » Mon Mar 04, 2019 12:34 pm

Fire rotation is a measure of the amount of fire in a landscape (the amount of time required to burn an area the size of the study area). The fire rotation statistic is best used for large areas that have mapped historic fire events.
Fire regime - Wikipedia

Recently a 'fire geek' friend of mine sent me the attachment below. As sent, it just had the last year's fires. I played around with different years, and then chose "All Years".
The following map demonstrates how significantly fire has shaped the California landscape over the last one hundred years !
Fire rotation, historic fire regime...
Fire rotation, historic fire regime...
For those who know the general geographic layout of the Central Valley of California, and how the coastal and the Sierra Nevada mountain ranges surround it, the location of the historic fires of the last hundred years define them well.
-Don
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

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dbhguru
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Re: The concept of fire rotation...

Post by dbhguru » Mon Mar 04, 2019 5:19 pm

Don,

Gee, shouldn't Californians have been raking and sweeping the woods all that time. Where have I heard that as the fire prevention prescription?

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Don
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Re: The concept of fire rotation...

Post by Don » Mon Mar 04, 2019 11:36 pm

Bob-
One of the hats i wore at Grand Canyon NP was that of field researcher. I was researching the effects of 1)no treatment, 2)thinning by hand and pile burning, 3)raking 'doughnuts around large old ponderosa pines, 4)broadcast control burning. An Americorps crew provided the 'person' power for treatments 2 and 3, and the GCNP's control fire crews for treatment 4.

But that was over 80 acres, and a lot of planning by all involved preceded the actual research.
The California wildfires by and large were in rural to remote mountain landscapes. Land managers with in the 'red zone' included USFS, NPS, California Fire, private timber industry, and some private ownership. The simple act of raking on landscape scales should reasonably be subject to environmental impact statements (my research went through one). Should it be done? Probably...by who? Managed by who? Financed by who? Which presidential term could it be initiated in? And would ten years be soon enough to return for another rotation of raking? Would future presidential/congressional entities support periodic raking?

Now that wildfires are occurring in urban landscapes, the public's attention, especially in California, is rapt ! Will there be changes coming? PG&E is declaring bankruptcy over the San Bruno Fire in the Bay Area some years back, and again in the recent Camp Fire near Chico, California. Fires these days are burning half a million acres at a time, and more and more often including high value communities.

Even without the presence of timber harvesting during the same period (100 years), my read of the map is that the forests we see in California are in a large part the result of a natural wildfire regime. Timber harvesting has its own impact on forests, but no treatment is probably the cause of the severe dieback occurring across much of the Sierra Nevadas (I've seen some of it, usually in periodicals including widespread senescing crowns). We've interrupted the natural fire regime by fire suppression, and in some part environmental litigation strategies that focused on 'no treatment' solutions.

The best "fire prevention prescription" (in fire adapted forest ecosystems) is the reintroduction of controlled fire in concert with thinning (mechanical thinning of ladder fuel, with pile burns). Yellowstone NP and Grand Canyon NP fire agencies have made great strides since the Yellowstone Fire Complex in the 1980's. Fire managers have a lot of concerns to deal with, but their primary priorities are in order of importance: 1)the public, 2) the infrastructure, 3) the resource.
And....: ~ /
-Don
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
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dbhguru
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Re: The concept of fire rotation...

Post by dbhguru » Wed Mar 06, 2019 12:41 pm

Don,

It's a pleasure to get input from a real professional. We thank you. From your past experience, what different prescriptions are in order for the almost savanna-like ponderosa ecosystem of the Kaibab Plateau versus chaparral on the steep slopes of the Southern California Mountains? In my short hikes up Big Morango Canyon in the Little San Bernardino Mountains, I tried to visualize fire management scenarios there versus in he densely wooded gorges near San Gorgonio versus in the Rocky Mountains of southwestern Colorado where fires have been historically present, but now tend to be real conflagrations.

Believe it or not, there are voices here in wet Massachusetts that advocate prescriptions more applicable to t he dry western landscape. So, the public needs to be able to distinguish experienced voices from those poised to short term reap rewards by playing on public fears.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Don
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Re: The concept of fire rotation...

Post by Don » Sat Apr 11, 2020 6:28 pm

Bob-
I should have jumped on this, but reviewing date of your post, it occurred while Rhonda and I were celebrating our 30th Anniversary, and I suspect my mind was distracted for awhile.
Re your comments immediately above, your questions are apt. I have to digress to answer your first question;
1a)what different prescriptions are in order for the almost savanna-like ponderosa ecosystem of the Kaibab Plateau versus chaparral on the steep slopes of the Southern California Mountains? My two-fold response is that, unlike very few places in the greater SW, we have in the North Rim of the Grand Canyon, a forest most closely resembling the pre-settlement forests often depicted as "open, park-like", the result of intermittently low in burn severity (just burning grasses, not hot enough to burn the thick old-growth ponderosa pine bark; and frequent enough to consume the grasses, and the regenerating ponderosa undergrowth. This becomes a cyclic fire regime that is essentially self-sustaining. Ponderosa pines don't live forever like the redwoods/Sequoias, but because of their extractives, continue to remain in place, often for centuries, though dead. Especially those charred well up the trunk. Now, shift out of the pre-settlement fire prescription (driven by extraordinarily high incidence of lightning downstrikes during Arizona's monsoon season) to the stand responding to the pre-1900's extensive logging of the South (and to some extent, Northern Kaibab Plateau) Kaibab Plateau, you have a "perfect storm" of warmer than 'normal' temperatures in combination with higher than normal precipitation, and the combination that would serve to initiate much greater than normal regeneration of a second-growth ponderosa pine forest. Not something that was apparent in any one given snapshot, but resulted in "dense, 'frog-hair thickets' of ponderosa regeneration. These 'thickets' create ladders for wildfires to climb up into the larger crowns of remaining old-growth ponderosas. Put the frequent high winds of Spring-time on the Colorado Plateau, and later the high winds that often combine with the monsoonal lightning storms, and you have today's catastrophic wild-fire events that range across hundreds of thousands of acres in a single event.
1b) Re the "chaparral on the steep slopes of the Southern California Mountains", they are not a forest, but accurately described by some, as a fire-adapted woodland species. They are a pioneer species that come in quickly after a wildfire event. Manzanita are another. Not fit for man nor beast to traverse through. But they do a reasonable job of keeping the soil from totally eroding away. Steep slopes accelerate the fire through preheating the uphill chaparral, making for an incredibly hot wildfire, none that you'd want to be uphill from. They can easily outstrip a firefighters ability to climb the hill to escape. The Camp Fire in Northern California started from a poorly maintained Pacific Gas and Electric power line, burned downhill across the Feather River Canyon, and up the other side where the ridgeline that the town of Paradise was located. In about an hour. Typically a fire can be stopped easier when it's having to burn "against gravity"/downhill. This one was driven by high winds, burned through very dry mixed lower elevation pine forest (not ponderosa)/chapparal woodland, hot enough that ashes, cinders, and smaller branch segments were blown ahead, starting fire across the canyon before the original fire had got to the bottom. Paradise (seemingly unlikely name, but it was a nice town, where I lived for a year in the late-70's) didn't have a chance...alarm systems where working, were late in being sounded. There was only one road in and out of Paradise....the rest is history.
I'll halt here, as I may have in a way already answered your later questions...if you're a glutton for punishment, say the word, there's more to say.
-Don

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dbhguru
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Re: The concept of fire rotation...

Post by dbhguru » Sun Apr 12, 2020 10:54 am

Don,

Please give us more. One question I have is when we're talking about the chaparral on slopes, what is the prescription? Clearing the stuff opens the landscape up to more erosion doesn't it? So, what's to be done.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Don
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Re: The concept of fire rotation...

Post by Don » Mon May 04, 2020 1:40 pm

Bob-
Leave it be, road It well for access needed to protect the fools that build residences into the wildland urban interface, and have good exit strategy when catastrophic fire conditions begin to mount. Only the pressure of the burgeoning Southern California metropoli forces expansion into the otherwise treacherous chaparral. With Santa Ana wind conditions (desert heating seeking outlet through the Coachella Valley into the LA basin) a long time weather pattern (historically at the least) blowing hot air masses through the chaparral region, a single point ignition can cause thousand s of acres in very short order. These can be very high burn severity classification fires, which means that they consume all fuels down to the bedrock, and prevent revegetation for years, decades in some cases. LA was known in it's inception settlement-wise, as the Valley of Smokes.

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