News has arrived from Iceland that the world’s largest atmospheric carbon-grabbing apparatus is now up and running.

Built at a reported cost of at least $10 million, it will eventually take 4,000 metric tons of carbon dioxide from the air each year and, through a process of heating and filtration, capture carbon molecules and inject them deep into the Earth, where they will mineralize.

Critics (there are always critics) have said it is too expensive and doesn’t sequester enough carbon in the quest of our age: to check greenhouse gases and climate change.

But who knows? Maybe it will prove to be game-changing technology. We can’t predict the future with any certainty. Did people look at the Wright Flyer and say, “Will they charge me extra for my bags?”

But when I read about the carbon-sucking plant, named Orca, I keep coming back to the same thought: Don’t we already have a machine to take carbon out of the air and store it deep in the soil? We call it a tree.

Beyond a tree’s carbon-eating capabilities, it has other environmental assets. Its shade reduces the urban heat island effect and the need for air conditioning, and it creates its own life-sustaining ark for all the wondrous creatures in its orbit, including unseen but vital soil biology.

There is an Irish saying that “it is in the shelter of each other that the people live,” and for me, the “each other” includes trees. To the gardener, they are kindred spirits, pure and simple.

Trees occupied the landscape of my childhood before I got into gardening. In the playing fields next to my street, there were elms, lindens and — best of all for climbing — horse chestnuts. With a bar of toffee in my pocket, I would secrete myself high in the canopy of a tree and spend a wistful afternoon looking out through a veil of foliage, watching the other neighborhood kids playing. I still remember the feeling of being held.

Trees and their attendant contributions to our world should be every child’s birthright. It doesn’t matter to the 7-year-old who planted that tree half a century before; it just matters that someone did.

We are in prime tree-planting season, and even modest urban gardens will have room for a fresh tree. Some are brittle or weedy, and some get too big for their allotted space, so you have to be discerning. There’s always room somewhere for a redbud or a sweetbay magnolia or possibly a ginkgo. Look to the future and plant small trees, which will be better adapted to their new homes and soon outpace the unwieldy and root-butchered big, new tree.

As I may have mentioned, I have harbored a dream of tree-planting for a long time, even to the point of knowing what forms they will take. I anticipate a grassy apple orchard of the type Vincent van Gogh might like to paint, and a grove of white-barked birch trees where Robert Frost will pause one snowy evening, and a forest of hardwoods where I might bump into Winnie the Pooh and Piglet.

I have long thought that one of the most heroic deeds a person can accomplish is to go on a tree-planting spree in their 80s. I’m still a fair way short of that threshold, but let’s just say the curtain has gone up on Act 3, and it’s time to get a move on.

Now comes the hard part. I can’t create this garden of trees (and many other plants) while working in my day job and writing this column. This has to be the last. This is a sad moment, because my journey of horticultural discovery and delight over the past 27-plus years wouldn’t amount to much if I could not have shared it with my readers.

I have learned many things from you, especially that gardening matters to a whole lot of people. We know that, whatever personal or collective ills afflict our lives, the garden offers succor. It is a place of immediate connection to nature, somewhere we can find respite, even among the weeds.

On a cheerier note, every blank yard is merely a canvas upon which to paint some magic.

It is not possible to muse on garden writing at The Washington Post without mentioning the wry, wise Henry Mitchell. Henry’s garden in Northwest Washington was a jungle of hundreds of plants that he had purchased, divided, started from seed or received as gifts, all lovingly nurtured and fiendishly observed. He knew every plant, no matter how small. His writing was for the enrichment of us all, but his garden was for himself.

Here’s a typical musing from a column written 30 years ago this month, and just two years before his death: “Recently on television I saw a garden said to be the finest private garden in America and I thought it looked like a lot of work and money going on there and I wouldn’t have it if you gave it to me.”

He liked rarities such as the connoisseur’s rambling rose, Aviateur Bleriot, but he saw the same regal presence in a humble nasturtium or that fleshy summer annual no longer in vogue, portulaca.

As he wrote in the same column: “Nobody’s garden needs to look like another’s, and there is much to be said in favor of portulacas growing inside rubber tires, though perhaps not in front of Georgian mansions, but the point is that nothing should be in any garden that the gardener does not think is wonderful.”

Time for me to gin up some wonder.

Tip of the Week

Hug a tree.

— Adrian Higgins