Elliot Ranch ponderosa pine Levels-Of-Growing-Stock study in Tahoe National Forest of California

This data publication includes tree height, diameter at breast height (DBH at 4.5 feet), and tree condition measured every five years from 1969 to 2019 at the Elliot Ranch in Tahoe National Forest, California. Height to live crown was measured in all measurement years from 1969 until 1999. The study was established in 1969 by William W. Oliver, a Research Silviculturist at Pacific Southwest Forest and Range Experiment Station (currently, Pacific Southwest Research Station) as one of the joint, west-wide Level-Of-Growing-Stock study (LOGS) sites for even-aged ponderosa pine. The original plots were installed on 20-year-old ponderosa pine plantations regenerated with 6 by 8 foot spacing in spring 1950 following the Elliot Ranch Fire in 1949 that destroyed the young plantation planted after the McKenzie Mill Fire in 1936. Three replications of five growing-stock levels (GSLs; residual basal area in square feet per acre following thinning when quadratic mean diameter is 10 inches or greater): 40, 70, 100, 130, and 160 were randomly distributed across 15 total, 0.5 acre plots. All plots were buffered with a 30-foot isolation strip. Plots were occasionally rethinned back to the initial post-thinning basal area levels. Unfortunately, extensive mortality occurred in 2021 due to bark beetle infestation in the area and only a few trees survived in the plots. Therefore, the study was terminated.
When Cliff Meyer constructed the LOGS study plan in 1976 based on data analyses from the earlier observational plots established by field foresters in the Black Hills of South Dakota and Northern Idaho, young ponderosa pine management was in its infancy. Therefore, original objectives were "to determine (i) optimum stand densities for maximum growth of usable wood per tree and per hectare over a range of site qualities and average diameters and (ii) growth and yield obtainable with repeated thinning." Later, these installations have been used to test self-thinning boundary lines, resilience to biotic disturbances, and climate changes.
These data have been summarized in various publications since 1970, which are listed as cross-references below.