CASCO BAY, Maine — These are the summer days when the island is overrun with gifts. The raspberries are still ripe and the first of the blackberries have arrived bearing their sweet intimations of fall.

Food is there for the picking. To pass up this generosity would be a supreme act of ingratitude. So I head out this morning with my small bucket.

Along the dirt road there is a dilapidated stone wall. Blueberries and chokecherries, wildflowers and bushes have pushed their way around and under the remains, toppling what once marked the neat border of a seaside farm.

It is one of many such old walls that you stumble across here, souvenirs of the effort it took our 19th-century predecessors to cultivate a place where rocks were a more predictable crop than potatoes, and a more plentiful harvest than clams. The boulders, now accessorized with moss and displaced by thick tree roots, were once skillfully arranged. Now they linger as a landscape's memoir.

Coming upon these relics, I wonder again at the effort it took to make these walls, our New England monuments. When the farmers finished, did they step back, look at their immense work with satisfaction and say, "There. All done?" Was the wall their art or artifact? Was the border a legacy left to their heirs the way others leave books, pictures and to provide a permanent marker?

Permanence and transience are on my summer mind. A couple of weeks ago, Randy Pausch died at 47, having completed what many journalists are required to do in their first class: He wrote his own obituary. "The Last Lecture" became a YouTube sensation. As a book, it became a best-seller — upbeat, touching, passionate. It was meant as a posthumous gift, a message in a bottle floated out to his three young children in hope that it would somehow help them cope with the loss of him. There. All done.

Not much earlier, Tim Russert also died, setting off days of televised mourning. In the untimely death of this vibrant, ebullient 58-year-old newsman, many of his baby-boomer peers saw the first foreshadowing of their own mortality. Since then, friends have asked with full recognition of their absurdity, how could Tim die before the election was over? How could he die in the middle of the story? As if we weren't all, always, in the middle of our own story.

But if transience is on my mind, if the luxury of summer comes with its own penumbra of loss, it's largely because there is a dying in my family. My Aunt Lorna is facing death with the trademark honesty and character that have marked her life and her approach to an unforgiving illness.

A few weeks ago, a new grandson arrived in the midst of her dying. She has already built a web of memories with her adored granddaughter. Now comes this little boy. A boy who will know her only through our stories. It was, she told me in one succinct word, bittersweet.

I roll that word around in my mind now as I step over boulders, drawn greedily from one bush to another. An island friend calls our land Bittersweet Farm. The nickname comes from the tenacious vine that arrived here long before we did and trespasses over our property with utter disregard for our borders, reaching out to strangle anything as immobile as a lilac or an apple tree.

I wage war with bittersweet the way the old island farmers waged war with stones. When I temporarily beat back the enemy, I too look with satisfaction, declaring victory — "There. Done." — and then smile at my own arrogance.

Like many writers, I use words to try and save the sand castle from the tide. Like many grandparents, I take pictures to lock the 5- and 6-year-olds in time. I step back from the keyboard or the camera and say, "There. Done." As if it were ever done.

In some way, we all try to mark our own territory. We want the byline for our labor. We excavate stones and build walls out of them. We create lives. Then nature, in its benign indifference, takes over, upending the illusion of power and permanence.

So here I am this morning, out where the land has upended the human wall, casting stones aside. Enough berries have grown in its place to fill my bucket to the brim. And the day is bittersweet.

Ellen Goodman is a columnist for The Boston Globe. Reach her at ellengoodman@globe.com.