Over 100 years ago, a chemist in Kansas documented that cottonwood sap contained methane bubbles. He could light escaping gas and watch a blue flame flicker. Others discovered that not only cottonwoods produce the gas.
Methane is a powerful greenhouse gas and today, thanks to global warming, we need to understand the ins and outs of methane in the atmosphere. New studies show:
Many instances in which trees produce their own methane—sometimes from microbes in the heartwood or other tissues and in other cases from a remarkable direct photochemical reaction thought to be driven by the ultraviolet wavelengths in sunlight. NatGeo
Life writes its name with methane, which is why methane on Mars is so exciting. On Earth, methane is released from fossil fuels, microbes in soggy soil like bogs and rice paddies, and (as you know) cattle. Human activities accelerate emissions – sometimes, we do in a year what nature does in centuries.
Methanotroph microbes also break down methane. The life expectancy of an average methane molecule is a few decades.
Trees emit methane and break it down by hosting the wily microbes and also on their own. The balance depends on the tree and soil conditions, but there are “forests where similar trees in similar soils have been measured with a fiftyfold difference in methane emissions… [Forests] in wet soils uniformly were net emitters of methane but those in drier conditions in some regions actually were net absorbers of the gas.”
One scientists said that what we know today is “a third grader’s cartoon drawing of a forest.”
None of this means trees are bad! Trees good. Forests good. But learning more about Earth’s methane cycle will improve our models and, if we’re smart enough, help us hand a beautiful world to our progeny.