Microplot Method for Updating Loop Frequency Range Trend Data: TheoreticalConsiderations and a Computer Simulation

摘要

Quantitative forms of the relationships between 3/4-inch loop frequency data(Parker 3-step) and data from the Community Structure Analysis (CSA) sampling method were determined from computer simulations of grassland vegetation populations. Percent basal area (measured using the CSA microplot) had a stronger and simpler relationship with Parker frequency than did CSA canopy cover, CSA density, or CSA frequency. Data from three or more 100-foot transects from homogeneous locations had significantly higher precision than data collected from single transects. A table for converting Parker data to percent basal area was developed for plants with mean basal diameters between 0.3 and 33.6 cm. Conversion of old Parker data to basal area should provide a basis for ecological interpretation of long-term changes in range vegetation.