In front of our home is a magnificent black oak. It's the biggest and most beautifully formed tree on the block. Not only does it provide welcome shade during our hot, humid summers, but it's home to lots of birds and squirrels—and three swings hang on ropes high in its stout branches.

The swings are commercial grade, like you would see at a park, because my husband, "Papa," likes well-made equipment that lasts. Fortunately, they are an unobtrusive green and blend well enough not to offend our neighbors.

In summer, no matter how hot it is, the tree provides enough shade for swinging. Grandkids' voices call out, "Papa, Papa, push me!" as soon as the children untangle themselves from their car seats and jump out into our driveway. Papa pushes them and pretends that he can't get out of the way as he lets them bump into him. Sometimes he falls to the ground, landing with his feet in the air—drama worthy of a stunt man. The first time my daughter saw Papa in action, she shook her head and asked whether he'd been a rodeo clown in a past life. His routine never seems to grow old; the grandkids howl every time.

In the fall, Papa rakes the abundant multicolored leaves into giant piles at the base of each swing and our grandchildren collapse in belly laughs as they swing through the heaps, scattering the leaves with their feet. Papa tirelessly rakes the leaves back into place for the next assault. Sometimes Papa acts as if he has tripped over his rake and, after an acrobatic attempt at trying not to fall, down he goes. He crawls under the leaves and hides until the grandkids come looking for him.

In winter, Papa's tree looks stunning with a covering of bright white snow contrasted with the dark gray of its stark, leafless limbs. Even then, if the temperature and wind aren't too extreme, our grandchildren beg to play on the swings. Now and then there's a perfect snowfall and Papa shovels it into mounds so the older grandkids can leap from the swings and land safely in the fluff.

In the spring our otherwise healthy, well-tended lawn comes to life with three bare spots. As Papa mows and fertilizes, he looks at those spots and smiles. He knows that at any minute a van could pull into the driveway and he will hear, "Papa, papa, push me," and he won't be able to convince them that it's too muddy. He'll just clean their shoes when they're finished.

We have six grandchildren who live close by, and they often visit at the same time. That mighty oak has room for several more swings, but Papa and I agree that the anticipation of having to wait their turn holds a lesson in patience and makes it more fun.

At least 10 extra minutes have to be factored into getting the grandkids loaded to go home. Their parents sigh and accept that it's impossible to walk by Papa's tree without one last swing.

Papa's tree feels like part of the family. And unlike the grandkids, it remains constant, its growth imperceptible in our daily life, while we watch the grandkids grow faster with every passing year. When they are grown and their visits come less often, Papa's tree will serve as an enduring reminder of these happy memories for all of us.