Yusuke punched a ton of demons into the sky and later Yomi vs Yusuke likely fight on a different tree entirely. Yusuke was already off that tree by the time Kurama defeated Shigure so why tf would you scale it all off that one tree when clearly some okunen trees are larger than others?
Hell if you look onto the okunen trees themselves you can see it isn't
that large as you can scale things to the clearly average sized trees and
clearly not multi-kilometre wide lakes.
Anime does say they are "several kilos" in diameter but still.