Some of them really don’t want to be touched.

As a misanthrope who spends far too much time jammed into tiny crevices on public transportation, I frequently find myself wishing the rest of my species would just back. off. my. shit. I was heartened to learn recently that trees feel similarly.

If you’ve ever looked up at a forest canopy and seen sunlight pouring through the cracks between trees, you’ve seen “crown shyness” in action. Crown shyness is a real ecological term referring to the phenomenon of how tree tops avoid touching, which creates channels and fissures in their crowns.

Scientists first realized that tree canopies have gaps back in the 1920s. But to date, no one’s been able to definitively say what causes these buffers.

Ecologists have theories, of course. Some believe wind is a major contributor and that when tree branches collide, the subsequent abrasion causes trees to lose leaves and eventually, alter their growth patterns altogether. Others hypothesize that trees are protecting themselves against shading — the more light they receive, the more their leaves photosynthesize. Scientists also think crown shyness might be a means of deterring harmful insects from spreading.

Part of the confusion regarding crown shyness stems from the fact that tree crowns are innately difficult to study because of their height (unless, of course, you take a quick sojourn to tree climbing school). In recent years, scientists have been able to leverage the invention of the laser rangefinder to help measure crown spread and forest canopies, but the mystery surrounding crown shyness remains unsolved.

We may never completely understand what causes crown shyness, but as humans, we can certainly relate. Everyone needs some personal space — even trees.