Art Cooper (1998, personal conversation): Frank Gates corresponded with F. X. Schumacher (forest mensurationist at Duke) about his 50 year plots study. Schumacher said only one problem - there was no replication. In 1967 when Art was teaching Plant Ecology here he found out about the 50 year plots and discovered he could tie in the work the class was doing (biomass allometric equations) to that data. They might be able to build a better picture of succession, but there was no sense of the variability of the aspen forest. So Nancy Worley put in more reference plots all on the same soil type - she used the cover type maps.