The Level-of-Growing-Stock (LOGS) study on thinning ponderosa pine forests in the US West: A long-term collaborative experiment in density management

The Levels-of-Growing-Stock study for ponderosa pine was a collective effort among western Research Stations within the US Forest Service. The experiment was established to test sustainable productivity across a wide range of densities by periodically thinning the plots. Beyond the original purposes for wood production, contemporary applications of these long-term studies have been to determine stand density effects on (i) both overstory and understory responses to stand development of even-aged ponderosa pine, (ii) biomass accumulation and carbon sequestration, (iii) plant diversity and wildlife habitats, and (iv) forest resiliency to insects and pathogens, droughts, and wildfires. Furthermore, these installations have served as a showpiece for the public and natural laboratories for professional foresters and students. For the past half century, the study has helped guide land managers and stakeholders on public and private lands about the value of thinning in overstocked young stands of ponderosa pine across its range. We hope that it will continue to serve as a springboard for addressing future issues facing forest management.