Why is the tree one of the hardest things to get right in 3d games?

[A Black Falcon]

Stunning shots of some buildings in PGR3 for X360.

http://ve3d.ign.com/articles/629/629819p1.html




Ingame screenshots of PGR3.

http://www.bizarreonline.net/index.php?a...ts=1&id=30







Maybe they look better up close, but from a distance... I know, I know, trees are hard because they aren't square and they have lots of small, branching parts. But those trees, honestly, don't look much better than the classic (and abymal) crossed-sprites tree...