Hi Lindsey, it’s the light! The shadows of the trees will be 180 degrees to the light, yet the bend in the road is in shadow. The open mid ground beyond the bright green grass looks like it is in shadow or is too dark and the shade on the tree itself is 90 degrees with the lighter trunk facing the darkest shadow.

Looks as though you've found it already!

Hi Lindsey. Theres an area on the forum where artists can ask for advice from other members. You will find it here https://www.painters-online.co.uk/forum/works-for-critique/ - worth posting for some help!