I answer the “why are trees so tall” question at http://whirledofideas.blogspot.com/2015/05/why-are-trees-tall.html . The rough answer is that height limiting treaties need to be enforced, and enforcement is costly, and for the most obvious enforcement mechanism that trees have available (negative allelopathy), enforcement is not observable by other trees. So if any trees did enforce a height limiting treaty, the trees that freeloaded on their enforcement would out-compete them, and that’s why we see tall trees and not height-treaty-limited trees.
I answer the “why are trees so tall” question at http://whirledofideas.blogspot.com/2015/05/why-are-trees-tall.html . The rough answer is that height limiting treaties need to be enforced, and enforcement is costly, and for the most obvious enforcement mechanism that trees have available (negative allelopathy), enforcement is not observable by other trees. So if any trees did enforce a height limiting treaty, the trees that freeloaded on their enforcement would out-compete them, and that’s why we see tall trees and not height-treaty-limited trees.
Praise our lord Moloch for giving us trees in which shades we can rest!