What do you call these little bits of the sky you see through a forest? Is there a word for it? Would you just use a word like little clear areas or holes? I am not sure how to express this.
We don't have a phrase for the holes, but we do have a phrase for the light:
Dappled light refers to that spotted light which typically comes through gaps in a tree canopy.
"Dappled" means covered in spots, and is often also used for horses and ponies.
A word with similar meaning is "mottled light".
I don't know of a single word for this idea. Nor do I know a standard phrase. English speakers trying to express this idea just describe it. "The sky visible between the trees", "the sky seen through the forest", etc.
We get a lot of questions on here about "what is a single word meaning ..." Maybe other languages often have single words to describe very specific ideas. But routinely in English, when we want to describe something specific, we use several words. Like we don't have separate words for "father's mother" and "mother's mother". We just say "father's mother" and "mother's mother".
Sometimes there is a single word, but it's rarely used, or only used in technical discussions.