At this time of year, one of the things I most love about where we live is watching the shifting shades of green. This year the trees leafed out while we were in Texas visiting family. When we left the branches were still bare. When we returned, everything was that extraordinary chartreuse of brand-new chlorophyll, so bright it's almost fluorescent. Baby green with a hint of neon behind it.

Only a few weeks have passed since that trip, but already the landscape has shifted. Most of the trees are wreathed in mature green now, a green that feels more substantial. Often the leaves are larger, too; they've reached what I think of as their summer size. I forget, every winter, what it looks like when trees explode with leaves. They go from sticks to puffballs, from stark lines to rustling softness.

I catch my thoughts snagging on thorns: these leaves are so beautiful, I'm going to miss them when they're gone. Or I notice the long low light of early-summer evening, and even as I'm reveling in this moment the whisper comes: someday the light will wane and the days will be short. Where did that come from? Why can't I be in this moment, instead of worrying about losses I might someday feel?

The leaves have only just grown; the summer's barely begun; the light is still increasing. Why am I already thinking about what it will be like to lose them? But this is what the mind does: it tells stories about things which haven't yet come to pass. Sometimes they are sweet stories, as when I anticipate seeing a loved one. Sometimes they are stories marinated in old fear: what you have will go away.

When I notice my mind spiraling down those old fearful pathways, I try to pause and take a deep breath, and on the exhale, to let those thoughts go. The thoughts happen. It's okay; there's nothing wrong with having them; and I don't need to become attached to them. I can notice them, name them, and then let them slip away like goldfish darting beneath the surface of a pond.

One of my favorite evening prayers is the ma'ariv aravim, the prayer which blesses God Who "evens out the evenings." The word comes from a root which means to mix; in this context it seems to hint at mixing afternoon with night. "You roll back light before dark, and dark before light," the prayer says (in translation). Light and dark take turns, and our task is to notice and sanctify the changes.

"You make the seasons change and order the stars in their appointed paths across heaven's dome," that prayer reminds us. The changes in season are part of the divine design; they are built into the world as we know it. In order for the season to hold still the earth would have to stop spinning -- catastrophe. God is the One Who cycles us through change, and change doesn't have to mean loss.

The Hebrew word for year, shanah, relates to the word for change, shinui. The year is made up of change, and God is the very process of change -- God Who describes God's-self, at the burning bush, as Ehyeh asher Ehyeh, "I Am Becoming Who I Am Becoming." The trick is to trust the hand of God at work. Change is how the world is renewed. Our task is to embrace that, and not to be afraid.