IT IS A STRANGE thing that many people do every year with the leaves of autumn (although perhaps not quite so strange as this year's spectacle of the leaves of autumn falling atop a foot of snow.) They rake them up, stuff them into plastic garbage bags and pile them up in great green mounds at curbside to be carted off by sanitation trucks.

What makes it strange is that leaves aren't a bad thing to have around. Strewn over one's property, they do offend against tidiness, but when chewed up by the lawnmower they enrich the soil, and piled in a compost heap in a corner of the back yard, they compact themselves over time and eventually decompose into a fine humus suitable for nourishing lawns, gardens and flower beds.

Pent up in indestructible plastic bags, however, they do little more than fill the landfills that much faster. Leaves, grass clippings, twigs and branches account for something like a fifth of the waste hauled away from homes in this area.

The New York Times carried a report recently from Long Island, a place whose notoriety as the home of the world-traveling Islip garbage barge has imparted a certain urgency to the search for alternatives to landfill. Communities there and in equally hard-pressed parts of New Jersey and Connecticut are moving more and more toward composting of such benign wastes -- particularly of the massive annual inundation of leaves.

The governments in the Washington area practice composting to some degree. It's still on a pretty small scale (most of the leaves continue to go into plastic bags), but space for trash is dwindling here, too, and public works departments are getting very interested in expanding such recycling efforts. (In Fairfax County, humus from the limited composting program is offered free to gardeners; in the District it's used on park plantings.)

Meanwhile, more people who live in leafy places and have a little space might want to consider devoting a corner of it to composting. Better to recycle leaves now than wait until we have to start sending them on expensive sea cruises.