Low poly forest. Please focused Critiques :) Blender 2.91

[LerryQuesso_Low_Pol (Lerry Quesso Low Poly)]

Hey, there. I’m just learning Any advice from senior colleagues? Thanks!

Video is here:
LINK: https://www.youtube.com/watch?v=cFvPpv-fTGE
3d Model is here:
LINK: https://www.blendswap.com/blend/27379

[Boder (Boh Doer van Deckle Schmidt III)]

Why are there rocks on the sides? And blue ones?