As I was on my way home, coming over a bump of the land and seeing laid out before me the neat fields and not-so-tidy scrub woods, it struck me suddenly. The wild trees in these parts are not large or tall--probably no more than 60-70 feet, most of them; and their roots can't go terribly deep, because there is rock not so far below the surface. So from top to bottom of a tree hereabouts is probably in the neighbourhood of 100 feet. Big domestic trees, like my three big storm-scarred maples, are taller and more deeply rooted--maybe as much as 200 feet from crown to root bottom. And of course there are places on this earth where the trees get REALLY big; sequoias, I gather, can get up to 350 feet, which means with root systems they're probably at least 500 feet from crown to toes. On the other hand, there are other places, like the High Arctic, where the top-to-bottom of the native flora is maybe a couple of feet, maximum.

Birds, of course, can go higher up than trees, although I don't know how high--maybe a few hundred feet above the land? It can't be too far, because the air becomes too thin to bear them up; and also, why should they go higher than they need to? And of course there are squishy and fascinating things on the sea bed at depths of maybe a couple of thousand feet.

So the life of the earth, from soaring hawk to sea cucumber takes place in a up-down range of maybe a mile and a half, unless you could our habit of getting up to above cloud level in self-propelled tin boxes. Of that life, the vast bulk, both in biomass and number of species, exists within the vertical equivalent of one long city block, just above, and just below the face of the planet.

I don't think it ever occured to me before, how thin this living skin of the Earth is. Think of the bulk of the planet, and think of the thickness of the biosphere, and you realize that the area where we live and have our being is thinner than a layer of paint on a very big beachball (probably far thinner than that, actually). Now, there is a thought to sit down in front of, and stare at for a while. That's something to make you go outside and find a piece of lawn, or a patch of woods, or a city park, and simply stare at it in bemusement and wonder.

And yet, thin doesn't mean fragile. This skin may be thin, but it's as tough as spider's silk (which has a tensile strength greater than the very best steel). It is tremendously tenacious; however we wound it, tearing at it in our selfishness, life pushes its way back, healing itself, regulating itself. If (as seems increasingly likely these days) we eventually do ourselves in through climate change, turning most of this earth into desert and swamp and wasting ourselves out of existence, this skin-of-the-earth-thing will wait us out, go through another of its transitions, and come back in a new form, with or without us.

What fascinates me, though, is not just the thinness and toughness of this skin, but its connectedness. The grass in your backyard uptakes the carbon dioxide from my compost bin and produces oxygen for the dog next door, whom my cats torment. The cat long-ago buried in the old vegetable garden (we put his body down a groundhog hole) has long since been converted into carbon dioxide and is probably part of the spruce trees by now. You simply cannot take one bit of this skin in isolation, not without making the conditions hopelessly artificial. It is a unity, and we are part of it.

We are part of a unity with each other, too; your suffering should make me weep, and my joy should make you laugh. One of the worst things we do to ourselves and each other is to erect divisions where none should exist. I guess we feel overwhelmed otherwise, and maybe for that reason it's necessary. If you could truly feel all the pain out there, it would swamp you--imagine what we put God through, that way! But the fact remains that when we look at each other or ourselves as free-standing non-interdependent units, we're lying in Mother Nature's face. Because there is no such thing alive on the face of this earth.

Look at it, this thin, tough skin, in all its beauty and complexity, and think: this is what God made: "The earth is the Lord's and all that is in it; the world and those who live in it; for he has founded it on the seas, and established it on the rivers." Take this creation seriously, for this is the work God knows and loves infinitely better than we ever can: "Who laid its cornerstone when the morning stars sang together and all the heavenly beings shouted for joy?"

It is God's green earth, and it nourishes and sustains us. Take time to wonder at its complexity--at our God's "inordinate fondness for beetles", at the shape of an elm, at the miraculous properties of water, at the beauty of a squirrel scrambling through the branches, the shape of the pigeon's breast. Pay attention to it. Turn it over in your mind. Go look at it, and think of that thin, tough, exuberent, resilient skin of life, and smile. Think of God's joy in this creation. And do it no harm.