Trees Talking in Fredericton
Assisted and inspired by Dr. Rod Savidge, my hydrophone was placed inside a white spruce in his Fredericton backyard. A hole was drilled into the tree about a meter off the ground, and about an inch deep. The hydrophone was wedged gently in so that the sides of the hydrophone were touching the tree. We then pulled and tapped the tree and listened to it creak and pop.
Creaking and schrunchling from the innards of the tree.
Dr. Savidge’s theory was this: In conifers like the white spruce, “tracheids” are very small cells that are responsible for all water movement throughout the tree. The tracheids have “bordered pits” which are like valves. The tracheids overlap with each other and as osmotic pressures from the tree draw the water from the soil up to the leaves, it passes through these valves. Temperature changes causes gasses in the water to expand and the pressure generated by the expanding gas separates the tracheids from other membranes and the valves will close. Somehow, in a way yet to be explained, the gasses explode, and make small popping sounds. We listened for these, and thought we could hear very quiet popping, but another theory was that the sounds we heard were the tree reacting to the hole we carved using an electric drill and chisel.