BELLVUE, Colo. — Camille Stevens-Rumann, interim director at the Colorado Forest Restoration Institute and her research team are monitoring several species planted two years ago on a slope burned during the devastating 2020 Cameron Peak fire, which charred 326 square miles (844 square kilometers) in the Rocky Mountains of Colorado. They want to determine which species are likely to survive at various elevations, because climate change makes it difficult or impossible for many forests to regrow even decades after wildfires. As the gap between burned areas and replanting widens year after year, scientists see big challenges beyond where to put seedlings. The U.S. currently lacks the ability to collect enough seeds from living trees and the nursery capacity to grow seedlings for replanting on a scale anywhere close to stemming accelerating losses, researchers say. It also doesn’t have enough trained workers to plant and monitor trees.