“When I moved in, this neighborhood was beautiful and clean,” she said. If there was an ecological value to the lot next door, she didn’t see it.

“I hate it,” she said. “They don’t keep it up or nothing. It’s in bad shape. This neighborhood has really gone down.”

A man with a straw hat and a brown paper bag — Eddie Thomas, 55 — charged across the street. “When are you going to mow that place?” he yelled, including a few other words for emphasis. The answer, “Not today,” appeared neither to please nor surprise him.

Mr. Thomas lives in Ms. McGriff’s house, and Dr. Gardiner had met him in the yard before. “The first time we came out, he was very nice,” she said. “And every time we come back, he gets progressively more frustrated.” For this, Dr. Gardiner blamed him not at all.

With Ultra-Ex researchers visiting the site every week, “there’s 40 people walking around here, looking in the air, vacuuming the leaves,” she said. ”He’s sick of a lot of people coming up here and doing a lot of things, except the one thing he wants done. Which is to mow the grass.”

Driving away from Site 6 and Cleveland’s east side, you can imagine someone like Mr. Thomas cursing the unmown grass every morning and evening, for years on end. Until one day, he will look over from the porch and the grass will be gone. And a wood will have taken its place.