Windstorm Postscript - Why Trees Talk

Several people have asked me, "What is making the trees pop, crack, groan, and chatter?" No, it's not the branches rubbing together. Nor is it one tree scraping against another. And it's not a hanging branch blowing up against the trunk. It actually is the internal breaks in the tree itself. Incredible and hard to believe, but I've seen it with my own eyes. I don't know if this happens to other trees, but it has happened to these particular eucalyptus trees on my farm. 

Just about all the time one chainsaws down a tree, the truck cross section is smooth and beautiful. I've always like the look of the wood, so it's something I take notice to. So I was pretty surprised when this tree was dropped. The trunk showed internal cracks. They initially weren't as obvious as in the following photos, but within 24 hours the cracks widen considerably and were very easy to see. 

This particular tree had its crown broken by the wind, with part of it twisted right off. I saw some of it happen as the wind swirled, twisting the tree this way, then that way. Amazing wind. I had no idea that the twisting had internally damaged the tree until the trunk was cut into sections. Whoa! 

So I figure that as a strong wind blows a tree like this around, the wood tends to rub along the cracks. That's what creates the sound. 

Now that we've taken some of the noisy trees down, I see that cracks exist mainly in the branches, not the trunks. And now looking up in the canopy several weeks after the storm, I'm seeing that numerous branches are wilting and dying. Perhaps the twisting and cracking was severe enough to cause the affected branches to finally start dying. I'm no expert on trees, so it's just a guess.