Small tree seems to dance with no cause
Q: I have a profound mystery! This plant in my neighbor’s yard moves on its own in the absence of wind. It’s funny to see it dancing by itself in the landscape!
A: This is a delightful video! The plant really does seem to be moving without any wind present. But, in the absence of invisible gremlins pulling invisible ropes, there must be a slight breeze going on. This looks like several limbs that have sprouted from a cut ailanthus or sumac stump.
Both plants (and all trees for that matter) are naturally engineered to react to wind in such a way that minimizes damage. One way is to oscillate: swaying back and forth when a gust hits. Branches oscillate too, helping the tree bend but not break.
In your particular case, a very slight breeze has caused the branches to oscillate from side to side, giving the appearance of dancing.
Keep an eye on the plant as winter removes the leaves and again next spring. My bet is that as it grows taller the oscillation frequency will change and you’ll see a different anthropomorphic performance.