If you lived here 13,000 years ago, you wouldn’t have much choice for Christmas trees: It was spruce and jack pine everywhere you looked.
That’s one of the conclusions (although they don’t phrase it that way) from an analysis of multiple studies of pollen grains in lake sediment, which provide a vegetation snapshot back to when the glaciers retreated from New England. You can read the research, which was overseen by scientists at the Harvard Forest research site in Massachusetts, here.
In summary, the finding is that the dominant species in New England forests have changed multiple times over the millennia as climate has shifted.
In a way this is reassuring as we see our forests altered by invasive insects and climate change. But it’s not that reassuring, because natural forces made these changes for a couple thousand years, and human forces are making the changes over a couple decades. That’s like the difference between somebody patting your cheek and slapping you hard – they’re both the same action, but speeding it up creates a lot of unpleasant consequences.