A google image search for "木漏れ日" gets me about 50% beams and 50% patterns on the forest floor, so I don't think the difference is as clear cut as all that. But even on that basis, we then have two words--sunbeams for the beams and dappled light for the pattern--where the Japanese have only one. By the logic of the usual breathless linguistic fetishism that we see everywhere online, that means English has twice the reverence for the natural world that Japanese has.
I've heard people call it "sun rays" or "sun beams" in English, but it's definitely not a well defined concept.