Why do pine trees make a thumping noise?
March 9, 2012 6:23 PM Subscribe
Help me figure out why I hear and feel a thumping noise when I sit next to pine trees.
posted by huxham to Science & Nature (9 answers total) 10 users marked this as a favorite
A little background: I was in San José, Costa Rica, last summer and ended up reading in a park that had a few pine trees scattered around (I don't know the species, however). I sat on the ground with my back resting against a pine trunk.
It wasn't long before I started hearing a bizarre thumping noise. From what I could feel from the ground, it should have been somebody jumping/stomping or people hurling bowling balls onto the soil from the nearby house's roof. I looked around--nobody. I looked (okay, creeped) at the adjacent house and nothing was going on. I looked up the tree and no critters were scampering around or woodpeckers going to town. This continued to happen, so I just accepted it as part of the experience abroad and thought nothing of it.
Fast forward to this month. I go to school at a college in southern Arkansas, and nearby there's a very primitive park (read: cleared footpaths) on a bluff overlooking a river. Along the bluff's edge are pine trees exclusively, with deciduous trees on the bluff's side. Last Friday, I was doing some reading and rested my back against a pine's trunk and--you guessed it--the same dull, thumping noise happened again.
The sound and sensation is similar to somebody whacking a carpeted floor with their hand: a very muffled bump that you can feel if you're sitting on the floor. But, like in Costa Rica, nobody (and nothing) was to be found. I felt the thumping noise in the ground and in the trunk, so I was wondering if the pine tree itself was responsible for this noise--sap moving around?--or if a parasite was tunneling around inside or below.
Anyone have any clue what's going on here? I'm sure there's a scientific explanation for it, but it's things like this that would have made the ancients believe in tree spirits & such. I'm not losing sleep over this mystery pine thumping, but it sure is weird.