Behind the Laguna Honda Reservoir in San Francisco, a quiet transformation is underway. What was once a eucalyptus-choked hillside is now teeming with native plants, and this spring it welcomed back a rare visitor: the variable checkerspot butterfly.

“This hillside used to be dark, overgrown. Now it’s home to plants and pollinators,” says Damon Spigelman, veteran arborist with the Natural Resources and Lands Management (NRLM) division within the Water enterprise. “What we’re doing here is about biodiversity, infrastructure protection, and creating something sustainable for the future.”

About three years ago, Damon’s team began rethinking vegetation management, with a focus not on simply trimming trees – but on restoring native landscapes to promote biodiversity and healthy ecosystems. With support from the San Francisco Water Division, other NRLM staff, and volunteers from the California Native Plant Society, the team has planted hundreds of native species grown from seeds at the SFPUC’s Sunol Native Plant Nursery. “It’s a thoughtful approach,” Damon says. “We don’t just remove trees, we come back in with a plan to re-seed, stabilize slopes, and support long-term care.”

More than 1,000 volunteer hours have powered the effort, and it’s already paying off. Lisa Wayne, Watershed Resources Manager, made the most exciting discovery yet in March. “This morning, we found 20 caterpillars of the variable checkerspot,” she says. “This butterfly depends on scrophularia californica, a native plant, as its sole source of food. When we planted it, they came back. That’s restoration in action.”

 

The work goes beyond ecology. The Laguna Honda Reservoir is part of our emergency firefighting water system, and removing large trees reduces the risk of damage and ensures access to this emergency water source. Damon checks in with crews daily, coordinates maintenance work, and monitors the plants season by season. Their current projects include widening the walking paths for accessibility, stabilizing slopes, and managing weeds. 

“It’s a full circle moment for me,” Damon says. “I’ve been a tree guy my whole life. But this – this is different. This connects to efforts across the city that include Twin Peaks, Sutro, and Mount Davidson. It’s a citywide effort. And it’s the kind of legacy we want to leave behind.”