I wish I had been able to join the students from the GreenMount School in Remington and Independence School in Hampden on Arbor Day as they planted 40 small trees along Stony Run. Besides being fun, initiatives like this one by the Baltimore City Forestry Conservancy and others by organizations like Baltimore Tree Trust and Parks & People Foundation make an impact.

Baltimore City has set a goal of doubling the tree canopy from 20 per cent to 40 per cent by 2037. A larger tree canopy adds beauty to a city and helps remove carbon dioxide and pollutants from the air.

Engaging students and residents in tree planting and maintenance activities is also a broadening educational experience. It helps increase the chances that trees will receive better care over the years. Planting trees is one thing. Watering and caring for them is another. Having watering bags attached to newly planted trees is a great idea. Unless adjacent property owners make sure to fill them during dry spells, they do no good.

Planting and caring for trees is one way I can make a tiny difference in the environment. Since my family moved to this house in 1959, we have lost all but three original trees. A red cedar, a crape myrtle and a silver maple are still standing. Having the silver maple pruned occasionally has kept the cars and house safe.

Since I moved back home in 1984, we have planted 15 trees. The birds brought two volunteer redbud seedlings that are currently twigs. I am letting them grow. They are not in bad locations. I am itching to plant another. Redbuds are natives, and we have not planted many of those. When I spearheaded the tree planting initiative here, I was too young and too ignorant to think in terms of native trees.

In 1989, we planted two Yoshino cherry trees, one on the site of our old playhouse and one where an ancient elm developed Dutch elm disease. We planted a Japanese zelkova at the back of the garden, where we had lost a sycamore. The umbrella shape of the zelkova adds is eyecatching, even though this massive tree creates a lot of shade over a once sunny garden.

We planted five Leyland cypress trees to make the Cold Spring Lane traffic less visible and a Kousa dogwood to soften the corner of the nearby garage. We planted a Foster's holly to mask a utility pole, but snow and wind broke it in two one blizzard night. Ditto a new Foster's holly beside the house.

We planted an Okame cherry tree where a native chokecherry died after a painter poured turpentine in an adjacent French drain. We planted a white native dogwood after an original was lost to anthracnose.

The new dogwood died mysteriously last summer, and we removed the stump last week. I miss it. A white dogwood has always grown outside my bedroom. Since I've already lost two on that site, I will not replant another there. Likely, the replacement will be an evergreen shrub instead of a tree. Any tree in the narrow space beside the house stretches towards the afternoon sun and looks crooked.

Last fall, we had to take a hemlock down that had been planted when the house was built. It had been one of a pair by the front door. (The other was removed 30 years ago.) The remaining hemlock grew taller than the house and caught the wind, which is fierce at the top of our hill. During the derecho, the tree kept slamming into the front porch gutter. In heavy snows, its branches scraped against the slate roof. Finally, my husband and our tree man persuaded me to remove it.

Now, the front of the house looks bare. I am trying to figure what to plant somewhere on the west side.

"Not big," says my husband, and he is right. One of two red maples the city planted will eventually provide a canopy. Another native dogwood tempts me, as does a Japanese maple like one at our neighbor's. A native eastern redbud would have similar dark red leaves. An Eastern whitebud is another idea. But both have wide spreads and might eventually obscure the house.

What tree to plant in the front yard is one of many puzzles that will keep me busy all gardening season.