Terrain Tree Shadows Bug(?)

Hello!

I recently added shadows to a scene, but there seems to be some kind of error with the shadow casting on the trees. The image below displays the issue:

There are two problems with the shadows. The red circles show the first issue: it seems that the branches around the trees have some kind of individual shadow that surrounds the branch. Additionally, the blue line indicates a kind of transparent square that accompanies the branch shadows. These invisible squares tend to interfere with other shadows (the shadow from the farther tree should be visible, whereas the invisible square obstructs it). Below is another angle:

I can't seem to find any other examples of this online, so perhaps it's an issue relating to transferring to Unity 5. Does anyone know how to resolve this? Any help is appreciated. Thanks! EDIT: Looks like the first image wasn't loading properly. It should be fixed. Sorry!