According to this article:
Trespass to land occurs where a person directly enters upon another's land without permission, or remains upon the land, or places or projects. This tort is actionable per se without the need to prove damage.
By contrast, nuisance is an indirect interference with another’s use and enjoyment of land, and normally requires proof of damage to be actionable.
What determines what actions can be brought per se, and which ones require actual damages to be actionable? And what is the law’s rationale for this distinction?