Forests of the Colorado Front Range Wildfire Crisis Strategy (WCS) Landscape were once made up of fire-resilient stands that were structurally different than the overly dense and homogenous dry conifer forests that are common in the region today. In the last two decades, many thousands of acres in the Colorado Front Range have received mechanical forest restoration treatments to reduce the risk of uncharacteristically severe wildfires. However, a key question remains: What conditions should we be restoring the forest to?

Information on historical forest structure  - such as tree density, tree species composition, and spatial patterns - can inform the design and implementation of mechanical restoration treatment prescriptions by providing insight into past fire-resilient conditions. This project will combine existing and new dendrochronologically- based historical forest structure characteristics with site-specific conditions to characterize historical forest structure in the Colorado Front Range Wildfire Crisis Strategy (WCS) Landscape, and assess how historical structure varied across the Landscape.

Photo Credit

The photo on the left was taken in 1896, courtesy of Denver Water. The center photo was taken in September 2000 by Merrill Kaufmann and the photo on the right was taken in September 2022 by Paula Fornwalt.

Repeat photos overlooking a hillside on the Pike National Forest, Colorado, show the changes in forest structure since the late 1800s.

Objectives:

1. Examine how historical, non-spatial tree and forest structure characteristics (e.g., total basal area, density, and quadratic mean diameter) varied along environmental gradients (e.g., elevation, aspect, and soil type) using existing dendrochronological data.
2. Examine how historical, spatial forest structure characteristics (e.g., tree spatial patterning, number of trees per tree group, and canopy cover of tree groups) varied along environmental gradients using existing dendrochronological data.. 
3. Use existing and new data collected in a rare, old-growth ponderosa pine stand at the Manitou Experimental Forest to characterize historical spatial forest structure across a broad range of spatial scales.

Expected Project Results

Outputs:

• Management-oriented scientific articles that will provide managers and other audiences with detailed information about the historical reconstructions of forest structure in the Colorado Front Range.
• Archived datasets of dendrochronological forest structure data. Archiving the project data will allow them to be re-utilized in novel ways by others.
• A decision support tool that will allow managers to easily incorporate the findings into their forest management prescriptions. 
• In-person and online presentations at conferences, meetings, workshops, and webinar series that will transfer our high-level findings and our tool to managers and other audiences.
• Additionally, the project team will work with managers to restore the old-growth ponderosa pine stand at the Manitou Experimental Forest to a more fire-resilient, historically-appropriate condition. This plot can be used as a demonstration site for managers and researchers.

Expected Outcomes:

This project will result in information and tools that can be used by managers in the Colorado Front Range WCS Landscape and other dry conifer forests who are conducting mechanical restoration treatments to promote ecologically-appropriate and fire-resilient forest structures. The results should allow managers to better tailor their mechanical forest restoration treatment prescriptions by integrating ecologically-appropriate historical non-spatial and spatial forest structure information. Ultimately, this project aims to helps dry conifer forests become more fire resilient in the Colorado Front Range and beyond.