Colorado Front Range Mountain Pine Beetle Outlook: Current Conditions, Future Potential Susceptibility and Capacity to Process Impacted Volume

Currently, across nine Colorado Front Range counties, MPB activity is relatively low albeit increasingly visible. From a proportion of county acreage, most of the current outbreaks occupy less than 1% of their total ponderosa pine-dominant acreage, except for Clear Creek County, where 2.8% of their ponderosa pine acreage is currently impacted, using severity-adjusted aerial survey acreage (Table 2). While these numbers are low, thinking about potential expansions of 1 km and 2.5 km over the next few years, the amount of impacted acreage may dramatically increase due to the presence of many spot infestations across these landscapes (Table 3). While current volumes impacted presently within outbreak centers are relatively small, this too is subject to dramatic growth depending on how quickly MPB moves through these areas.

Warmer winter temperatures favor MPB larval survival and development, while cold winter temperatures often present bottlenecks to MPB population growth (Amman, 1973). The winter of 2025-2026 was one of the warmest winters since Colorado temperatures were first recorded in 1895 and showcased a statewide snow drought (NOAA, 2026; Schumacher, 2026). Snowpack often provides critical early season moisture for lower-elevation forests, suggesting that, even with some welcome precipitation this spring, ponderosa pine forests will be drought stressed earlier and potentially for longer this summer. Given this climate reality and the fact that ponderosa pine forests within the nine-county analysis region are largely comprised of individuals at highest risk for infestation, this does not suggest the outbreak will begin to wane anytime soon.

Our volume estimates suggest that under low levels of infestation, Front Range mill capacity to utilize materials generated will be overwhelmed. The volumes presented represent a combination of potential future management and impact responses, rather than any single treatment type. These include sanitation (e.g., the felling and removal of currently infested trees before MPB flight), pre-emptive management to reduce susceptibility before MPB arrives (e.g., thinning to reduce stand density and average tree size) and fuels reduction to remove dead fuels generated by MPB. They center on areas immediately adjacent to current infestation centers and likely the places to be first hit as the outbreak expands.

The high potential volumes surrounding current infestation centers and the low capacity of Front Range mills portend the challenges faced as we move through this outbreak. Assessing tradeoffs among different management strategies and their outcomes will be paramount. While alternative biomass industries, like biochar, show promise as an outlet for low-quality wood products, they face logistical and economic challenges at larger scales. Leaving woody residues on-site following management activities, as another potential action, impacts subsequent fire and other pest behaviors by maintaining large fuel loads in place. Practices like pile burning represent an immediate loss of stored carbon to the atmosphere. Low capacity among Front Range processing facilities will limit economic opportunities to offset treatment costs through wood utilization. This challenge is compounded by ponderosa pine’s limited market appeal relative to lodgepole and spruce, and by the geographic reality that over half of Front Range roundwood capacity sits in Fremont and Pueblo counties, well outside the core outbreak area, limiting accessible capacity further. More information on woody biomass utilization options is available from the CSFS Biomass Assessment.

This emphasizes the need for conservative approaches to cutting since treatments are likely to be expensive and resources stretched thin across varying landscapes. Collectively, this suggests that, to make the best use of limited resources, we need to effectively prioritize management spatially to have the biggest impact on outbreak progression/remediation.

Management of this outbreak will bring controversy associated with tree removal. However, by leveraging FIA data, we can begin to develop potential mitigation opportunities. Future analyses during this outbreak will consider the spatial makeup of ponderosa pine forests along the Front Range to provide land managers with areas under highest risk for current outbreaks, as well as areas most suited to potential proactive management to reduce MPB-related mortality as it arrives.

Additionally, pre-emptive management to reduce structural characteristics associated with increased infestation potential should precede MPB arrival by at least a few years for the best results. While reducing density within forests may increase resources and may temporarily boost defensive abilities immediately following treatment, these are ephemeral and subject to variability as resources fluctuate (e.g., ongoing drought). Allocation of resources to the formation of increased structural defense (i.e., resin ducts) generally lags a few years behind management actions (e.g., Vilà-Vilardell et al., 2024). We do not intend to support management for management’s sake, but the fact that mill capacity is exceedingly low highlights that treatment costs will remain high and thus the need to be targeted in our approach within both MPB-killed and current green forested stands.

Given that this potential outbreak is occurring mainly in lower-elevation ponderosa pine forests, this means a greater population will be directly impacted by increased hazards associated with tree mortality events. Short-term impacts implicate safety concerns for roadways and ingress/egress routes, complications to wildfire suppression (although, for a more complete discussion on the intersection between MPB and wildfire severity, see this Science & Data Byte), among other threats to public and private infrastructure across the state. Long-term, depending on damage, impacts may include species composition shifts, decreased ecosystem resilience and the need for reforestation, among other ecological outcomes. Therefore, assessing the current status of the outbreak and future potential impacts is important.

Not discussed in this publication is the fact that these ponderosa pine-dominant forests are not completely comprised of ponderosa pine. Colorado’s lower montane, including dry mixed-conifer forests, host a wide variety of associated tree and shrub species. Compared to the outbreak in lodgepole pine in the late 1990s, where vast acreages were comprised of largely one species, lower montane forests contain a diversity of conifers and angiosperms that may attenuate the impacts of MPB. Ponderosa pine is an important species from a climate change perspective, but the diversity of species present within these forests may help maintain ecosystem services.

Ponderosa has also been most heavily impacted by 100 years of fire suppression, which may explain the relatively low levels of age-class diversity amongst ponderosa individuals specifically within the current analysis. Coupled with targeted reforestation efforts, which will be boosted by the reopening of the CSFS Nursery in 2026, we can assist areas in recovery while simultaneously managing green forests ahead of the outbreak, thereby maintaining this key tree species on the landscape. This is to say: We do not expect the complete mortality of ponderosa pine, but we will have to deal with potential impacts for years – and decades – to come.