Evaluating tree growth dynamics in restored ponderosa pine stands to develop maintenance and timber harvesting schedules
Increasing the pace and scale of ecological restoration treatments in ponderosa pine forests of the western United States is a major goal of several federal policy initiatives. As a part of the Infrastructure Investment and Jobs Act and Wildfire Crisis Strategy implementation, scientists are working to better understand spatial patterns of tree regeneration, tree growth, and forest development following restoration treatments in ponderosa pine forests. Information gained from this project will provide decision-makers with the knowledge and tools to design forest management operations and maintenance schedules that achieve future fire behavior, stand structure, and ecosystem service goals. This project will ultimately help managers determine what timber volumes can be sustainably produced in uneven-aged forests while simultaneously providing a variety of ecosystem services.
Forest restoration treatments aim to create low-density stands with a matrix of individual trees, groups of trees, and openings that mimic pre-European colonization forest structures of the area. However, much of our current understanding of forest stand dynamics is based on data from even- aged and uniformly spaced forests. To better create and maintain spatially complex restoration treatments, a better understanding of forest growth dynamics, such as tree regeneration, tree growth, and resiliency to disturbances like insects and wildfire is needed.
This project is a collaborative effort among scientists at USDA Forest Service Rocky Mountain Research Station, Colorado State University, and National Forest Service practitioners to better understand the growth and development dynamics of ponderosa pine forests following restoration treatments. The research team will collect data on the stand development across the Colorado Front Range Wildfire Crisis Strategy (WCS) Landscape and will use that data to simulate changes in stand structure, seedling regeneration, and wildfire behavior over time. This information can inform potential trade-offs of forest restoration, fuel reduction, and timber harvest activities. Forest restoration treatments also need maintenance to retain their ecological and wildfire risk reduction benefits. Information gained in this project will be used to modify decision support tools such as the Forest Vegetation Simulator and provide decision-makers with sufficient knowledge to design forest management and maintenance operations that meet the desired future fire behavior and stand structure condition goals. The research team will also develop ecologically appropriate timber harvesting and restoration maintenance schedules that will help forest managers plan their work. The project results will directly support efforts across Collaborative Forest Landscape Restoration Program and Wildfire Crisis Strategy Landscapes.
Research Objectives
The objective of this project is to develop and deliver of sound scientific research that advances USDA and Agency goals of reducing wildland fire risk and fostering resilient forests and watersheds. Specifically, this project aims to:
- Understand the spatial patterns of new tree regeneration and ingrowth establishment in previously restored, spatially complex ponderosa pine sites.
- Understand forest restoration treatment longevity by simulating the growth and development of trees in the previously restored sites over time, using the Forest Vegetation Simulation (FVS) and field-collected stem-mapped data.
- Assess the changes in wildfire hazard over time as the stands develop using a fire-behavior model that can incorporate spatially complex forest structures.
- Develop maintenance and timber harvesting schedules for restoration treatments in spatially complex ponderosa pine forest to maintain resiliency over time.
- Evaluate the accuracy and precision of using FVS to estimate tree growth in spatially complex forests.
Expected Project Results
Outputs
- A network of demonstration areas that provide land managers and stakeholders examples of fuel reduction and restoration treatments along with site-level information on growth, development, and treatment longevity.
- Published peer-reviewed research articles and manager-focused bulletins on the research findings and management applications.
- Outreach and presentations to local stakeholders, natural resource professionals, and scientists at regional, national, and international engagements through webinars, site visits, and conferences.
- Continued contribution to a database of stem-mapped forested stands with tree growth for future remeasurement and analyses.
- Integration of key findings into the Forest Vegetation Simulator (FVS), a forest growth simulator used by the USFS.
Expected Outcomes
- The Forest Vegetation Simulator (FVS) will be able to more accurately simulate forest development trajectories in complex forests to better inform future timber production opportunities and prioritize treatment and maintenance needs.
- Researchers and practitioners will have increased knowledge and conceptual understanding around the tradeoffs between restoring spatial complexity, increasing tree establishment, and potential fire behavior results.
- The ecologically appropriate forest restoration maintenance guidelines developed from this project will be used to plan fuels reduction and restoration maintenance in ponderosa pine forests, ultimately helping to increase the longevity of treatment resiliency benefits.
