I'm not really sure what I think of this law. It's probably based on the types of laws that prevent one person from planting trees that block another person's established views.

Anyway, that aside, it sounds like the article has made some kind of factual error. It starts out by saying you need to consider your neighbor's existing trees, but the law it quotes specifies trees planted "subsequent to the installation of a solar collector..." So it seems like if the trees are already there, they are safe, but if the solar collector is there first, it has "dibs" on the sun that falls on it. If that's the way it is applied, then it seems fair to me. You should not be able to make someone cut down an established tree, but you should also not be able to ruin another person's investment in a power system by planting a new tree to block it.