Colorado foresters expect mountain pine beetle activity to increase substantially this year, raising concerns for forests, drinking-water sources and communities along the Front Range. The insects have already damaged ponderosa pines near mountain communities west of Denver. Infested acreage grew 148% in 2025 compared with the previous year, reaching 5,544 acres, according to the Colorado State Forest Service. State entomologist Dan West expects activity to be two to three times higher this year than last. The threat spans more than 600,000 acres of ponderosa forest in nine counties where about 4 million people live. Beetles are moving through forests from the Boulder area toward Colorado Springs, with potential impacts to trees near homes, roads and watersheds. A dry period has left many pines less able to fend off the insects. Beetles bore beneath the bark and disrupt a tree’s flow of water and nutrients, often killing it within a year. West found unusually large numbers of larvae in trees this spring; cold temperatures that can kill beetles were largely absent over the winter. The outbreak is also creating expensive choices for property owners. In Evergreen, retired environmental science professor Harv Teitelbaum spent $10,000 to remove 45 infested ponderosas from his property. About 40 more trees there are dead or dying. Some residents have received removal estimates as high as $15,000 per acre. Treatments can help protect individual trees, but they carry costs of their own. Arborist Brad Huddleston said insecticide injections can cost up to $300 per tree every other year, while pheromone packets and sprays cost as much as $25 per tree. Removing hazardous trees and disposing of infested wood adds further expense. The consequences extend beyond property lines. At least a quarter of Denver Water’s 2.5-million-acre watershed is covered in ponderosa pine. The utility has spent $96 million since 2010 on forest restoration, including efforts to protect selected trees from infestation. Watershed planning manager Madelene McDonald said intense wildfires can send sediment into water supplies, increasing treatment costs. Officials are concerned that dead and dying trees could worsen wildfire conditions. Jefferson County collected 10.3 million pounds of woody debris in 2025, up from 9.5 million the year before. But communities have limited capacity to process the volume of wood, and a dry winter led counties statewide to ban slash burning, a disposal method used by some landowners. The state’s 39-member Ponderosa Mountain Pine Beetle Task Force, formed after Gov. Jared Polis issued an executive order in December, is working on prevention and response. Its recommendations include protecting high-value trees, removing trees that may shelter beetle broods and improving coordination among government agencies and landowners. The task force’s work plan also identified gaps in public communication, staffing and funding. Those gaps are especially challenging where forests cross federal, state and private land. Clear Creek County Commissioner George Marlin said local officials need more resources to carry out mitigation, including around the Clear Creek Watershed, which serves 450,000 people. Early detection is central to the response. Some newly infested trees remain green and can be difficult to spot, but signs may include sawdust near the base, sap on the trunk or tunnels beneath the bark. Foresters say homeowners should seek advice from qualified arborists and prioritize trees that are infested or pose a hazard. The task force has warned that the outbreak could continue for a decade or longer, with visible tree losses and elevated fire risk. For residents and local governments, the immediate challenge is finding the money, workers and infrastructure to respond at a scale that matches the spread.