By the calendar, strict dividing lines separate Winter from Spring and Summer from Fall. The natural world knows no hard and fast boundaries. In the middle of August I stepped outside this morning to find an acorn on the ground. Looking around, I found many more, and along with them a smattering of fallen oak leaves. I’ve found birch, maple and mountain ash leaves on the ground as well. Even in the peak of summer, we’re beginning a long coast into autumn.