Classification and clustering analysis of standing dead trees and associated park asset wildfire vulnerability in Yellowstone National Park

Abstract

In the Rocky Mountain and Pacific Northwest regions of the United States, forests include extensive portions of standing dead trees. These regions showcase an intriguing phenomenon where the combined biomass of standing dead trees surpasses that of fallen and decomposing woody debris. This stems from a suite of factors including pest disturbances, management decisions, and a changing climate. With increasingly dry and hot conditions, dead timber on a landscape increases the probability that a fire will occur. Identifying and characterizing the presence of standing dead trees on a landscape helps with forest management efforts including reductions in the wildfire hazard presented by the trees, and vulnerability of nearby park assets should the trees burn. Using forest-based classification, exploratory data analysis, and cluster vulnerability analysis, this study characterized the occurrence and implications of standing dead trees within Yellowstone National Park. The findings show standing dead trees across the entire study area with varying densities. These clusters were cross-referenced with vulnerability parameters of distance to roads, distance to trails, distance to water, distance to buildings, and slope. These parameters inform fire ignition, propagation, and impact. The weighted sum of these parameters was used to determine the vulnerability incurred on the park assets by the clusters and showed the highest values nearest to park entrances and points of interest. High vulnerability clusters warrant priority management to reduce wildfire impact. The framework of this study can be applied to other sites and incorporate additional vulnerability variables to assess forest fuel and impact. This can provide a reference for management to prioritize areas for resource conservation and improve fire prevention and suppression efficiency.