Christmas Day was a glorious day on Plum Island. A cloudless sky of powder blue, brisk northwest wind and chilly temperatures made it the consummate winter day in coastal northern New England. It was a perfect day for a walk on the beach.

While walking on the beach, I passed by a sand dune my family used to own. I still remember listening in on the phone call when I was 5 or 6 years old — it might be the oldest memory I have — when old Mr. Walton, the owner of the small hotel and cottages we used to rent each summer, called to tell my parents he was retiring and wanted to offer them the business. My parents, each of whom had successful careers going in New York City, were in no way going to become hoteliers on a decrepit little island in Massachusetts, but they were interested in the empty lot at the south end of Walton’s property.

Fast forward 40-plus years and there have been a lot of changes. Walton’s got sold to a couple named the Syrenes (I believe that’s how they spelled their names) who sold off the cottages and upgraded the hotel a bit. More in line with their probable motives for buying the place, they built themselves a huge house onto the south end of the hotel. Plum Island transformed over the years into a much more upscale place, with most of the cottages becoming big showpiece houses (a conflicting process, it must be admitted, my parents were one of the first to prompt) and the island itself becoming more of a destination.

The Syrenes later sold the hotel and the big-ass house to Jeanne Geiger and her husband (he of the Aeropostale brand and fortune). She was deep in the throes of her bid to remake Plum Island into some kind of “The Hamptons North,” so they turned the hotel into a boutique joint named “Blue,” complete with driveways full of those little blue, glass pebbles you put at the bottom of an aquarium, and bought damn near all of the other available commercial properties on the island.

Jeanne Geiger died in a tragic accident, I believe at the house, and over the ensuing years her husband sold off most, if not all, of their other properties on the island. The hotel went to a company in nearby Amesbury, Mass., that manages other high-end, boutique resorts in places like Cape Cod. Blue is now once again open for business and the prices are insane.

On the south side of the lot my parents bought was an asshole who over the years turned his house into some sort of suburban New Jersey mafioso’s home, complete with statuary, an all-encompassing lattice work surrounding the place and a gazebo on the dune in front. He also encroached onto our property at least a couple of times before, in a fit of supreme arrogance, he tried to take the lot by adverse possession. I am not shitting you.

My parents were a hell of a lot kinder than I would have been. Things went to court and they allowed the encroachments to stay (in exchange for a pittance in cash) and also negotiated that the asshole would have right of first refusal should the time ever come to sell.

And all through the years, that time apparently never came. My parents always held out the idea that someday they’d build on that lot. It would be a smaller place than our family home just up the street, and it would be right on the beach overlooking the Atlantic Ocean. Never mind that the lot was too damned small to ever really build on, or that the environmental laws were never going to allow construction on such a dune (although truth be told: if you grease the right palms in Newbury, you can build whatever you want wherever you want; zoning and environmental laws are really just suggestions in this town). And never mind that Dad was never going to leave the current house, even for one on the beach; the man was set in his ways, as many of you know.

Anyway, late in her life I used to bemoan to my mother the fact that she and my father had never really invested in the great stock market run-up of the ’90s –– despite the fact that Dad, a business reporter for the New York Times, was a peerless predictor of what the markets were going to do, and Mom, thanks to her business, had plenty of cash to spend. And Mom would always counter, “I know, but we invested in real estate.” To which I would always hold up this unbuildable lot on which they’d been paying taxes for decades and say, “Yes, badly.” (Yes, I realize I was being a bit of an asshole myself. I just thought they should have been able to live more easily than they did late in their lives, that’s all.) Mom always used to talk up investing in land, often citing Will Rogers’ dictum that “they weren’t makin’ any more of it.” I think she believed in the permanence of place, and I’m sure the events of 1929 were still very fresh in her and my father’s minds. The Great Depression was not an abstract notion to them but a very real event through which they lived. And it all started with a stock market crash. So she invested in land as a result.

All of this history lesson ran through my head as I passed by the dune on Christmas Day. My father sold the lot a year or two after my mother passed, and the current owners, like many of those whose properties are right on the beach, have piled up car-sized boulders at the front of the dune, an effort to bulwark the island against the Atlantic Ocean that has, since the winter of 2012-13, been ferociously nipping at homes along several stretches of beach.

The irony, of course, is that in the case of this lot, Mom was investing in a sand dune on a barrier-beach island –– the very definition of impermanence. And today’s current beachfront owners aren’t just tossing pebbles before a tsunami, they’re accelerating the everyday erosion that’s endangering other homes on the island.

Anyone who thought Plum Island was permanent was a fool. Barrier-beach islands are designed by Mother Nature to move. We get to enjoy our time, however long or short, as residents/caretakers of the island, and when the ocean comes to collect the rent, well, it’s time to go. Plum Island, my family’s dune, we ourselves…it’s all such a short stay.

I’m not being morbid, but that impermanence was front and center on Christmas Day as I saw the rocks the current owners had placed to protect the dune emerging from the sand. And impermanence in general has been front and center as I’ve wondered what will become of my family’s house (in which my brother is currently living), what will become of Further, and what will become of me. The walking-on-the-beach-on-Christmas-Day version of “Stopping by Woods on a Snowy Evening,” (by my father’s favorite poet, no less) I guess.

Still, it was a gorgeous, gorgeous day.