Picture diagnosis

Shigo said, Aspen haven't quite learned how to be trees. They have almost no CODIT. It they're wounded they die.

For me there were clues. One was how the crack passed smoothly around a branch collar. The crack seemed to follow the grain. Another was the smooth curves of the crack. Any lightning tree I worked on had jagged edged wounds...more straight lines.

I don't know the names of decay organisms but the sooty black look is not what I see on burnt aspen. Soot washes off

I could be wrong of course...serve up the crow if so...but please let me have some https://shop.cholula.com/Green-Pepper-Hot-Sauce/p/CHS-GPEPPER&c=Cholula@HotSauces
 
I think "lighting" is the easy answer. I'm not saying it is wrong...but it makes a lot of sense and people can logically grasp how that damaged a tree without understanding anything else of tree behavior or biology.

I do NOT think we can rule out lightning based on damage pattern...it is extremely variable. I'm not saying that is the case here, but just that lack of splintering or a vertical vs. spiraling doesn't rule that out.

Frost crack: Synonymous with "sunscald" or "southwest injury", right? - caused by the sun warming the southwest side of the tree on a warm day then freezing hard at night. That is a long crack to be caused by sunscald...the bark on the lower trunk would be pretty thick for sunscald by the time the tree was tall enough for it to go that far up. That is a continuous crack, so I don't see it as one that happened low, then another happened higher up later. That certainly happens (I think....), but I'e never seen it continuous - usually they are offset. So I think I would rule that out as the initial cause of injury...but am willing to be talked into it!

Other "frost cracks" are caused when a previous injury is kept open by freeze cycles, right? Whether that be a branch wound, deer rub, tree falling against it, sunscald, etc...

My guess: previous injury was either a "minor" lightning strike or fibers being torn by a significant wind bending the trunk in the past. That wound is being kept open by frost cracking.
 
Here is a Kim Coder paragraph on lightning damage:
The most visible result of a lightning shock wave is the splitting open of bark and shallow radial cracking of the wood directly beneath the lightning path. The explosive shock can also cause the tree to flex and energetically rebound, causing bark and wood loosening or expulsion. The shock wave shears-off cellular connections, pulls wood fibers apart, and loosens bark, phloem, cambium, and xylem. Multiple strokes in a single lightning strike can generate multiple shock waves. The shock waves bounce off the inside of the tree stem and cause tree tissue shifts along the stem’s circumference.

Source: http://www.gfc.state.ga.us/community-forests/ask-the-arborist/LightningStruckTrees.pdf
 
JD3000 said:
Frost crack can occur on other sides of the tree sk is not synonymous with sunscald/sw
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I agree. However, the term doesn't have consistent use. I've seen it used as a synonym for sunscald from respectable sources. From a Michigan State publication:
"Frost cracks are often found on trees that are out in the open where sun shines directly on the bark. Cracks are first initiated on a winter’s day when sunlight warms the bark and inner wood on the south or west side of the tree, especially on young trees with thin bark. As the sun sets or is hidden by clouds, the temperatures drop quickly causing shrinkage in the bark while the inner wood takes longer to contract. This unequal shrinkage or contraction between the bark and the inner wood causes the bark to split and along with it the wood directly below the bark."

I try to avoid interchanging the two as I try to keep the term "frost crack" for other damage that is exacerbated by freezing and "sunscald" for ... well, sunscald.

My question was clarifying how Tom was using the term. Maybe I misread his use...
 
God bless the spark of creativity, JeffGu you made my day. On topic my neighbour had a less extreme sun scald vertical like that without the black on a juvenile maple. Grew in pretty lumpy after being covered a few years but closed up completely.
 
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Pretty common on the freeman maples around here. There is a whole neighborhood that had them planted for street trees. They were all the "right age" (about 6-8" DBH when the winter hit hard in a few years ago. All of them are now 10-12" and have scars - still open, but woundwood is developing well.
 
JeffGu said:
Ok, I think I know what happened. First, it got caught in a rainstorm and swelled up like an over-ripe cucumber and then @moss built a campfire on the south side of it and dried it out, then a woodpecker got his beak stuck in it and tried to pry the crack open with a crowbar (which he obviously borrowed from some nearby crows) and 1000 monkeys climbed it with 1000 typewriters so they could write some Shakespear, and then a clown car pulled up and a buttload of evil clowns built a trapeze in the thing for the fat lady with tattoos, then @JD3000 injected it with 47 different exotic, imported beers, and then it froze the following winter and was struck by an out of control government worker in a 6X truck, who only came there to cordone off the area as a possible crime scene and to put up some signs that said, "Forest closed due to clown infestation", then @Tom Dunlap's weird friends with an unhealthy fascination with the North Shore came along and held some kind of strange May Day festival around the tree, and an elephant climbed most of the way up it and tried using it for a pogo stick, and @oldoakman used it to practice his big swings into the adjacent trees (most of which he knocked over) and then the tree farted out its giant trunkcrack and accidentally ignited 5000 cow farts when a spark from @moss's campfire, which for some strange reason was still burning, ignited the fart gases and the tree's trunkcrack couldn't handle the sonic vibrations and split the whole way up the tree, causing climate change and political unrest throughout most of the known world. There, now you know. Case closed. Next pic, please.
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Move aside Shigo!! :)
 
Tom Dunlap said:
If this tree is inland from the lake it will be elevated about 50-100' above lakeshore. In the summer that is the difference between swimming and pants and jacket. In the winter it wouldn't be a surprise to have stretches of several days with highs barely in single digits and possibly -30* F or colder nights.

My eyes see frost crack. All of the lightning struck trees I ever worked on had splintered wood inside and more irregular edges like what might look like split American Elm. This looks like smooth grain splits like I've found when splitting aspen for camping in the Arrowhead.

The blackening, to my eyes, is decay micro organisms not charred wood. Charing always seem to wash away soon. this is so uniform and complete.

No wrong answers because no one can eyeball the tree.

This came from a Facebook query. There are about 100 replies. When I posted I included a link to frost cracking. During the course of the thread another arbo who has lived up there for his whole life agreed with me. When the OP read about frost cracks and our comments he agreed. Several others 'liked' our responses and some weighed in with thoughtful a

It was interesting reading the replies, which lead me to think about the two camps, lightning or frost cracks. Like too many facebook threads it seems like there are many people who guessed lightning. My guess is that this is the only thing they might know about. How many homeowners would know what frost cracks are if they were given the diagnosis? I rarely had any that did. Almost all of the time cracks to homeowners were blamed on lightning. After an explanation they could understand what cracks were.

ONe guy replied that he was hiking during a storm and saw an aspen on the trail get hit by lightning. Totally freaked of course! He said that the lightning crack was ragged not regular like in the pics.

The feeling from the thread, for me, was like in a friendly political facebook thread. Two camps. And so many that bring an opinion based on what they know but don't take time to read or learn. A buddy of mine in my neighborhood is on the rump side of politics. We agreed to not go deep on politics to keep from wrecking things. Neither of us tries to convince the other. We do share some views and reading material for knowledge not necessarily for persuasion. WE both have learned from the other.

My picture based diagnosis: Frost crack
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I have seen a lighting track that looked similar to this on a hardwood, however they usually have a little scalloping/unevenness along the length which would make it a little rarer.

I have also seen water swelling that looked very much like the pictures.

One question, what is the likely mechanism of frost cracking? Is it freezing of moisture on outside of cambium?
 
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