The Ishi Wilderness is a 41,339 acre (167 km²) area located in the Lassen National Forest in the Southern Cascade foothills of northern California, United States. The wilderness contains several mixed ponderosa pine and black oaks forests which were never logged and have experienced multiple wildfires in the 20th century which created forest conditions similar to those that occurred before fire suppression (Smokey the Bear).
Stand changes brought on by fire exclusion have contributed to reduced resilience to wildfire in ponderosa pine forests throughout the western US. Growing recognition of how structural attributes influence resilience has led to interest in restoring more heterogeneous conditions once common in these forests, but key information about interactions between stand and fuel development in such stands is currently incomplete or lacking. Few contemporary examples of structurally restored old-growth ponderosa pine forest exist. In this study, we propose to re-measure plots in the Beaver Creek Pinery, a remote site in the Ishi Wilderness on the Lassen NF in California, that were installed following a 1994 wildfire, to better understand forest and fuel succession overtime. The BCP experienced five wildfires since 1900 that restored the structure to one believed similar to historical ponderosa pine forest. Overstory and understory vegetation will be quantified at 107 circular plots systematically arranged across the BCP, and all trees, saplings and seedlings will be mapped and measured in six one hectare plots to examine variation at multiple scales. We will also examine the performance of California Black Oak, a declining but important species valued by tribes for foodand wildlife for habitat, to better understand how fire interval and severity maintain the conifer and oak mixture. These data are essential for identifying the persistent effects of fire on spatial heterogeneity and fire resilience that are needed for guiding fuels management, especially in landscapes that are designated to use fire as the primary tool for fuels and vegetation management. This project will be broadly applicable to ponderosa pine forests throughout the western US. A great deal of effort iscurrently being expended to restore these systems reducing density, favoring larger more fire resistant trees, and promoting a more heterogeneous structure. Using data from the re-measurement, we will also model future stand and fuel development in 10 year time steps, thereby shedding light on how structurally restored forests are best maintained, including the maintenance interval.