Are there bacteria inside trees?

New research tells us about the microbiome of living trees

I have been taking trees apart for my whole life, as a kid out of curiosity and as a scientist with more specific goals (usually). As I take them apart, I can’t help but notice the variation in the smell of different parts. A lot of the variation in smell within a tree is probably due to the abundance of bacteria in different tree parts.

You probably know that humans contain a vast population of bacterial cells, especially on our skin and in our guts. We now know that the same is true of trees. A recent analysis of bacteria in the stems of trees shows that wood in the stem of a medium-size tree contains about a trillion cells of bacteria and archaea. If that seems like an enormous number, well it is, but it’s a lot fewer than inside of us, which is about 38 trillion.