In the absence of wildland fire, lodgepole pine forest managers use other techniques, such as thinning, to mimic the effect of fires in regenerating lodgepole pine stands. These efforts help diversify the age class and structure of the forest, which can reduce the impacts of disturbances like large-scale mountain pine beetle outbreaks. An example of this are younger stands of lodgepole pine in southeast Jackson County that regenerated from forest treatments in the 1990s. These younger stands were unaffected by the historic mountain pine beetle outbreak that killed most mature lodgepole across northwest Colorado in the early 2000s.
But these young lodgepole forest require continued stewardship. Many of the managed areas on the Colorado State Forest and Owl Mountain State Trust Lands have young lodgepole pine forest that would benefit from thinning; in fact, not carrying out these treatments will likely result in a forest that’s more vulnerable to insects, disease and wildfire. That’s why Colorado State Forest Service staff found funding to thin 600 acres on State Trust Lands to improve the health and resiliency of these lodgepole stands.
Creating a healthy lodgepole stand
After a stand-replacing event like a crown fire or clearcut, lodgepole pine regenerate profusely, and that’s what happened in Jackson County. Foresters usually consider 350-600 mature lodgepole pine per acre optimal for forest health. Regenerating lodgepole pine stands can grow back with densities from 2,000 to up to 100,000 trees per acre. Without follow-up management in the form of a thinning, these stands will develop more slowly and can be at increased risk from impacts of beetle outbreaks or fast-spreading wildfire. For dense stands of young lodgepole pine in Jackson County, CSFS foresters created a management plan that spaces trees 7-9 feet apart. Foresters refer to this type of thinning as “timber stand improvement” or “pre-commercial thinning.”
Foresters instruct contractors performing the work to keep the tallest and healthiest trees. This process also lets foresters increase species diversity through retention of non-lodgepole trees like aspen, spruce and fir. This increased diversity helps in making the forest more resilient.
Contractors thinned 259 acres in Jackson County in 2023, and another 350 acres is under contract and scheduled to receive similar treatment in 2025. They used two different thinning treatments:
- Contractors cut the trees with chainsaws and then piled the cut trees for pile burning in the winter.
- Felled trees are cut into smaller pieces and scattered around the forest floor; this process is called “lop and scatter.”
Benefits of thinning young lodgepole forests
Thinning these acres of lodgepole stands has significant positive impacts on the forest:
- Improve tree health and vigor
- Improve browse for grazing and wildlife
- Increase Snow Water Equivalent, making more water available
- Build resilience to wildfire and insect attack
- Improve future opportunities for sustainable timber harvest
These forest health projects in Jackson County are so important that they’ve received funding from multiple sources that understand the value they bring to the overall health of Colorado’s forests. By pooling funds from the North Park and Statewide Habitat Partnership programs, Colorado Water Conservation Board, State Land Board Enhancement Fund and the CPW Oil and Gas Mitigation Fund, the CSFS has put $490,000 toward creating a healthy, productive future for 600 acres of lodgepole pine stands in the Colorado State Forest and Owl Mountain State Trust Lands in Jackson County.