The NPR News article and podcast Getting Fire From A Tree Without Burning The Wood begins with
A scientist walks up to a cottonwood tree, sticks a hollow tube in the middle and then takes a lighter and flicks it. A jet of flame shoots out from the tube.
It seems like a magician's trick. Turns out, there's methane trapped in certain cottonwood trees. Methane is the gas in natural gas. It's also a powerful greenhouse gas.
and describes the discovery that quantities of methane have been observed to be produced within cottonwood trees.
There is a video of the methane tapped from a tree being set on fire.
The article continues:
"The wood in this particular species naturally has this condition called wetwood, where it's saturated within the trunk of the tree," says the lighter-flicking scientist, Oak Ridge environmental microbiologist Christopher Schadt.
This wetwood makes for a welcoming home for all sorts of microorganisms.
"You can't actually see a lot of the organisms because we can't grow a lot of these organisms," says Melissa Cregger, a staff scientist at Oak Ridge. "So we're able to identify them using their gene sequences."
Some of those organisms turned out to be species of archaea that are known methane producers. So it's not the trees themselves that are making the methane, it's the microbes living in the trees.
It's not clear to me if the use of "wetwood" refers to the natural condition of cottonwood trees, or if this is meant to refer to some kind of bacterial infection. For example, Mirriam-Webster defines wetwood as:
wood having a water-soaked or translucent appearance because of abnormally high water content sometimes due to bacteria and sometimes to physiological factors
Question: Is it unusual for populations of archaea to be found living inside trees? Is this something new and surprising or is this well documented?