Various models that I created, using small textures and low polygon count
Diffuse map - 512 x 512 (tileable)
Normal map - 256 x 256 (tileable)
Polycount : 136 tris (for one rock)
(trunks) Diffuse map - 256 x 256 (tileable)
(leaves) Diffuse map - 512 x 512
Polycount : 433 tris
(trunks) Diffuse map - 256 x 256 (tileable)
(leaves) Diffuse map - 512 x 512
Polycount : 865 tris (for one rock)
(Grass1) Diffuse map - 256 x 256 (Grass 2) Diffuse map - 512 x 256 (tileable)