Ponderosa pine Levels-of-Growing-Stock study: Tree measurement and condition data for Crawford Creek and Lookout Mountain in Oregon

Among the six installations located across the western United States of the ponderosa pine Levels-of-Growing-Stock (LOGS) study that began in the 1960's, the Pacific Northwest Forest and Range Experiment Station (currently, Pacific Northwest Research Station) has two installations that still exist today. One is Crawford Creek in the Blue Mountains on the Malheur National Forest in northeastern Oregon. The Crawford Creek site had 18 plots with six Growing Stock Levels (GSLs) (30, 60, 80, 100, 120, and 140 square feet per acre) installed on a 60-year-old, even-aged, natural ponderosa pine stand. Plot size ranged from 0.4 to 0.75 acre with additional 30-foot buffer strips. Plots were replicated in three blocks with six plots per block and were located across a range of aspects and slopes. The other site is on the south-facing slope of Lookout Mountain on the Pringle Falls Experimental Forest and adjacent to Deschutes National Forest in central Oregon. At the time of plot installation, it was a 65-year-old pure ponderosa pine natural stand. Six GSLs (30, 60, 80, 100, 120, and 150 square feet per acre) were randomly assigned to one of the three blocks, with a plot size of 0.5 acres with additional 30-foot buffer strips. Data collection began in 1967 at Crawford Creek and in 1965 at Lookout Mountain and continued roughly every 5 years until 2019. This data publication includes the tree height, diameter at breast height, height to base of live crown, and condition data collected at both sites.
When Cliff Myers designed the west-wide Levels-Of-Growing-Stock (LOGS) study for all installations across the western United States in 1967 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, the 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 were used to evaluate self-thinning boundary lines, resilience to biotic disturbances, and climate changes.
For information about the original design of the LOGS study, see Myers (1967). For more details about the data included in this package, see Barrett (1983).