Forest managers need to understand long-term stand changes in the forests and woodlands of Arizona. These data can reveal the basic ecologic dynamics of these ecosystems. They also can serve as a basis for projecting future changes and for forest simulation modeling. Sampling variability is reduced when the same transects, plots, or points and trees are visited during a series of inventories. Inventory designs and experimental plots were established throughout central and northern Arizona since the middle of the 20th century and much of the collected data have been documented and archived. Some examples of the usefulness of re-measuring these plots and points in ponderosa pine forests and pinyon-juniper woodlands are presented. Managers and researchers should make efforts to recover historical data to understand the ecologies of their forests and woodlands and to plan for ecologically sound management.