Rain fell freely on Casper Riordan without a tree canopy to temper it.
In a clearing between the urban forests of Alton Baker Park and Eastgate Woodlands, he led a small crew of volunteers working within a tight radius marked by bright neon flags — the boundary of their restoration project.
It’s a tough place for Riordan, a stewardship coordinator with the Walama Restoration Project, to find the right plants for. Inside this nearly 2-mile loop of Pre’s Trail is the 70-acre decommissioned Day Island Landfill. About 2 feet of soil — the landfill’s cap — lie between a decade’s worth of garbage and the native species he is trying to grow…