What happened to this maple?

[BryanEx]

I was walking my bush the other day and found this tree that I'm not sure what happened to it or if there's anything I can do about it. The wood is not split but the bark is from about 2 feet above the tap hole right to the ground with a hollow between the bark and wood. In the attached photos it looks like there are two tap holes but the lower one is just where the loose bark has fallen away where two cracks join. So far the canopy looks healthy with no die-back or wilting and it's the only tree I've found with this problem. My taps are set with a 7/16" tapping bit and I use a stop collar on the bit so my tap holes are consistent. The only thing I can think of that was any different was the odd season we had last year and several hard freeze/thaw cycles after pulling taps. Is it possible the bark splitting is freezing damage? Did I just hit a weak area of the tree when tapping? Has a pest used the tap hole to gain entry to the tree? Or my favourite... perhaps it's a wound from an alien laser gun. :rolleyes: It really bothers me that somehow I caused this damage so I'd like to figure out if it's from an error on my part or just the way it worked out from other circumstances.

[Haynes Forest Products]

To me it looks like sun scald. That is what happens to trees that face the south side. The sun heats up the bark in the winter and the tree starts to become active in that area of the tree.Then it freezes and thaws. It then dries out the cambian layer causing the bark to curl up and die. We end up wraping the trees every year in the fall. Trees will out grow it as the bark thickens. It happens alot to Maples and Ash because of the thin bark.

[BryanEx]

Thanks Haynes. This tree trunk would be in full sun in the spring when there are no leaves around but the crack is on the North-East side of the tree. Does that still make sense for sun scald?

[Haynes Forest Products]

Yes I lost a tree in my front yard from it. Google sun scald maple trees and read away. If you look at trees in the woods the outer trees on the edge of the woods take the brunt of the weather. Have you ever noticed paint dots on trees in nurseries thats painted on the tree before they dig it out of the ground. Most of the time when we replanted a tree we put the best side out and didnt care about it.

[farmall h]

yes...definately freezing action going on. Kinda small diameter tree for tapping don't you think?

[BryanEx]

Kinda small diameter tree for tapping don't you think?
I don't see a problem with tapping a 12 1/2" DBH tree but if the researchers are recommending a larger minimum taping size I'll certainly adjust my bush. I think it just looks smaller than it really is in the photos, probably from me making the file sizes small enough to add as attachments rather than having to use links. Either way, I won't be tapping it again until the wound has healed over anyway.

[DrTimPerkins]

What does the back side of the tree look like on the opposite of the blue dot? The stem looks a bit swollen at the height of the blue dot. Is there some sort of canker there?

[BryanEx]

Hello Dr. Perkins... the opposite side of the tree has a steep crotch about 1 foot above the level of the blue dot and small healed wounds from lost branches on the left and right side (as seen in the second photo). This was only the second year for tapping this particular tree. The first year's tap hole on the East side has completely healed over to the point I can barely find it with no bark splitting.

[DrTimPerkins]

Hello Dr. Perkins... the opposite side of the tree has a steep crotch about 1 foot above the level of the blue dot and small healed wounds from lost branches on the left and right side (as seen in the second photo). This was only the second year for tapping this particular tree. The first year's tap hole on the East side has completely healed over to the point I can barely find it with no bark splitting.

Sunscald and/or frost cracking usually occurs on the southern or southwest sides of trees, and is due to rapid temperature changes caused by localized solar heating followed by rapid drop in temperature when the sun goes down. It usually is also associated with something else.....either thinning of the stand to increase solar exposure, insect damage, or, commonly, some type of infection. Being on the north side is fairly unusual.

I suspect the branching just above the site where the crack is has allowed some infection to set in where the branch joins the stem, and that decay column extends downward for a long distance, predisposing the tree to frost-cracking along that axis. Hard to be sure without seeing it myself though. I'm not convinced it is sunscald...could just be a canker caused by that branching pattern.

Either way, not a lot to do about it. It should heal up over time if the tree is otherwise healthy, although it could be a while, and the crack could get bigger before it gets smaller. You could try painting the stem white, or wrapping, but you could also just leave it alone and see what happens.

If there are replacement trees nearby, I wouldn't take them out right away, but leave them until you're able to tell that this tree will recover alright.

[BryanEx]

I suspect the branching just above the site where the crack is has allowed some infection to set in where the branch joins the stem, and that decay column extends downward for a long distance, predisposing the tree to frost-cracking along that axis.

Good call Dr. Perkins! With the heat we're having locally this summer the bark has continued to crack and start to flake off so I went back for yet another closer look. I can now see why it cracked but still don't quite understand what caused the situation in the first place.

There is a split approximately 8 feet in height and 2 1/2 inches wide starting just above the root flare and extending straight up to about 1 1/2 feet above the blue dot in my original photo. That point is directly opposite the steep crotch on the other side of the tree. At some point it seems only the inner layer of bark split and that continued to open up as the tree grew but the surface remained intact with no signs of the void behind it. When I set my tap for last season I just missed the hollow space by 3/4 of an inch which was close enough to release the surface tension and start the cracking in the surface bark. The space between the bark and wood measures 1/4 inch or slightly less and the bottom 6 inches of the hollow was filled with a peat-like soil. There were tiny insects in the soil but it looks like they were confined to that area as there are no signs of boring, worm holes, or other infiltration. The sides of the split seem to have healed over and have strong adhesion to the wood. At this point I've removed any of the loose bark chunks that were falling off and brushed out the soil at the bottom to allow it to dry. I guess from here all I can do is let nature take it's course.

[Haynes Forest Products]

Looks like it already started to heal over. DONT tar it.

[BryanEx]

At this point I don't plan on doing anything with it and especially applying tar. I expect it will continue to grow just fine for years to come but if not... firewood. Just wondering though, is there any situation that tarring is actually beneficial? My understanding is that the practice does more harm than good because it creates a vapor barrier even though it was a common procedure years ago. I remember my parents doing it after pruning apple trees for example but don't know of anyone that recommends it these days.

[DrTimPerkins]

Just wondering though, is there any situation that tarring is actually beneficial?

On your driveway, yes. On trees, no. Trees are very good at compartmentalizing wounds. Leaving them alone is best.