Fire and forest history at Mount Rushmore.

Area of Science:

• Forest ecology
• Fire ecology
• Dendrochronology

Background:

• Mount Rushmore National Memorial is surrounded by ponderosa pine forests that have not experienced fire for over a century.
• Understanding historical fire regimes is crucial for managing current forest health and wildfire risk.

Observation:

• Dendroecological data and forest structure analysis were conducted across 29 plots.
• Historical fire regime reconstruction indicated low-severity surface fires with infrequent crown fire events.
• Current forest structure is denser, with more small trees and less large trees compared to historical conditions.

Findings:

• Historical fire intervals ranged from 16-34 years, with a fire rotation of 30 years for surface fires.
• The current forest structure exhibits lower canopy base heights and greater canopy bulk density.
• Fire behavior modeling predicts a shift from surface fire dominance historically to crown fire dominance in the current forest, especially under severe weather.

Implications:

• Changes in forest structure at Mount Rushmore mirror trends in southwestern ponderosa pine forests.
• Increased likelihood of crown fire necessitates forest restoration to prevent catastrophic wildfires.
• Restoration efforts are vital to protect the ecological and aesthetic integrity of Mount Rushmore.