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How do you tell when a forest fire happened?

Started by maestro, June 12, 2008, 06:41:39 PM

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maestro

We have adopted a section of the Ozark Trail to care for and maintain.  This is in the Trace Creek section near Potosi MO if you are interested in the location.  As we were making our way through our 4.45 miles we started noticing fire damage along the trail.  I've asked around and nobody (including the local Rangers) know anything about it.  I think I located the tree that was originally struck but was wondering if there is a simple way to estimate when the strike and fire happened?  I'm sure this can be done scientifically but I don't know any off hand and there really isn't a way to poll everyone who may have walked the trail for the last few years. 

Just curious, seems the more I do in the woods the more I see and am fascinated by! 
For in the true nature of things, if we rightly consider, every green tree is far more glorious than if it were made of gold and silver.  Martin Luther

BaldBob

If there is callus growth (scar tissue - tree trying to overcome the wound) around the fire scar, use an increment borer to bore into the callus growth and count the rings back to the fire scar.  Another way, though slightly less reliable, if its been several years since the fire, is to cut one of the small trees on the site - one that was too small to have survived the fire - count its growth rings and add 1-3 years to its age to establish the year of the fire.
For more precise data, if weather records are available for the area for the year you determined the fire happened (per above methods) you might get lucky and find out when there was a lightning storm in the area.

Phorester


My first question would be, how did the fire start. How do you know the fire was caused by a lightning strike? 

maestro

Going to have to admit I have no clue for sure how the fire started, I'm just assuming it was a lightening strike.  There seems to be a pattern, more damage in the location where the tree in question is and less damage radiating from that area.  I'm not a fire expert nor do I claim to have any knowledge in this field.  My thoughts are based on observation alone, that's why I was hoping you guys might have more insight!   ;D The facts are this is a trail that isn't traveled much, we had a lot of maintenance (read overgrowth and unreported deadfall) to do.  There isn't any decent camping sites in the area in question and it would take a serious hike to access this area.  It just doesn't seem logical for a man made fire to be started in this location and it wasn't big enough to cause enough damage to be noticed by anyone in authority. 

For in the true nature of things, if we rightly consider, every green tree is far more glorious than if it were made of gold and silver.  Martin Luther

BaldBob

OK after reading more of what you have to say I get the impression that you are talking about a fire that happened relatively recently, not years ago.  If you can find herbaceous plants that were killed but not destroyed by the fire you can often determine the date of the fire within 1-2 weeks if not closer.  By noting the growth stage of the killed vegetation (e.g. peak of flowering, early seed development, bud set, stem elongation, etc.) someone familiar with the growth patterns of the species (e.g. a professor in the biology dept. of a local college) can tell you the date those plants reach that stage in that area and thus the time the fire occurred.

Ron Scott

Who's land was the fire on? The fire agency that suppressed the fire should have a fire report as to the date and time of the fire.
~Ron

Phorester


Maybe not Ron, if it was a little fire that burned itself out on a remote trail section like this  that no one saw, it might not have ever been reported.

Maestro, it could also have been a hiker that tossed a cigarette to the side of the trail, a child hiking with parents that played with matches. Two more causes of trail fires that I've found over the years of investigating these things. I'm not from Missouri but on most things you gotta "show me".  Unless there was a distinct lightening scar on a tree I wouldn't say that was the cause.

Fire patterns on trees can provide clues as to the origin.  Sounds like you might already know this, but the side of trees opposite the direction the fire came from always gets hotter than the side that was facing the fire.  So the fire char will be higher on the "back" side of the trees  Quite often on a hillside or a mountain the uphill side of numerous trees will have a fire scar from the ground up the trunk a few feet depending on how hot the fire was.  It will be an inverted V, the widest part at the ground and the point up on the trunk.  You can trace the damage back to the origin from these scars if you take your time.

Really though, the fire origin is not important in determining when the fire occured.  As BaldBob says, if the fire happened a few years ago I think your best bet is to bore a few trees in the callus ridge of the fire scars to determine how many years ago the damage occurred.  If you can't get an increment borer, cut a couple down and count the rings that way.  Go by his suggestions on recent vegetation changes if it happened just this year.

maestro

I won't be back in that area again until October but I'll see if I can't get any more details (direction, core, vegetation, etc.).  The land in question is gov't land, part of the Mark Twain forest and I did check with the Ranger station in charge of that area and they didn't know anything about a fire in the last several years.  Nothing big enough to be reported to anyone and must have put itself out. 

I'm just curious, no real reason for my quest.  Seems the deeper I get into conservation and the more time I spend studying about forests, the more things I notice when I'm out.  My girlfriend was with me and when I mentioned the fire damage, her response was "what fire damage".  lol. 

Thanks for the input so far, I'll see if I can't get any more real data.  Now, if someone could just explain why I wasn't so interested in learning when I was in school...
For in the true nature of things, if we rightly consider, every green tree is far more glorious than if it were made of gold and silver.  Martin Luther

beenthere

maestro
We do like to see pics, and this would be a good documentation of what you were seeing. 
Did I mention, we like pics... ;D ;D ;D

Any other documentation on the trail?  websites, etc. ??
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Phorester


"My girlfriend was with me and when I mentioned the fire damage, her response was "what fire damage". "

I've shown landowners and school kids alike fire damage on trees, and they don't believe it since there is years or decades of new lush growth all around them. Makes for an interesting learning experience for the ones who are open minded.

SwampDonkey

White pine often survive large fires or the dead stubs stand for decades while a new spruce-jack pine forest grows up around them. The germination of black spruce and jack pine is usually within a year or two of the fire. Just age the new forest and you have a close enough estimate of the fire year.

I was wondering how the uphill side of a tree burns hotter. I can envision the flames following the air flow around the trunk and possibly foiling on the back side. But, when you hold a blow torch to a stick of wood or piece of metal is it hotter on the back side? Seems like it would be hotter on the side facing the fire front. But I am recalling a rim of a wide valley that follows a small creek. The side of white pines, that went through a fire,  facing away from the valley was where the trees were gutted and often times it was a bit of a slope on that side so it could be considered the uphill side.

I guess I just answered my own inquiry. :D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Phorester

It's not analogous to holding a blow torch to a piece of wood.  Remember that a wildfire is traveling in air currents.  Visualize a rock in a stream.  The water splits, flows around the rock, then eddies on the downstream side of the rock.  Air flows around a tree the same as water around a rock.  If there is fire in that air, when it eddies on the downwind side of the tree it's holding the heat from the fire for a much longer time against that side of the tree.  So the "back" side of the tree, the leeward side, the side away from the fire orgin, whatever you want to call it,  gets hotter and therefore has a higher fire char on the trunk and has more damage done to it than the "front" of the tree that gets the initial blast of heat.

Normally during daylight hours, fire always travels uphill faster than on the level or downhill, since the air currents are being heated by the sun and the fire (hot air rises), so the air flows uphill faster than any other direction.  So other factors being equal, a fire on the slope of a hill or mountain will quickly begin traveling up the slope.  So the uphill side of the trees get the worst heat damage.

Obviously if the fire is intense enough the bark entirely around the tree gets hot enough to burn off and the tree is killed immediately.

SwampDonkey

Yeah, I always knew an uphill fire was faster than straight out on flat land. It was just hard getting my head around the idea it got hotter on the uphill side of a tree, away from the fire front. But, recalling about the pine fire helped me figure it out. I never studied fire science for over 15 years and never fought any fires. We never have more than grass fires in my local area.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

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