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Acocks measured representative sites of good condition grassland in the 1940's that were re-sampled approximately 50 years later in order to compare the effect of commercial versus communal grazing on compositional change. Most of the Mistbelt 'nGongoni Veld had been afforested, a third of Highland Sourveld or Northern Tall Grassveld had been transformed by cultivation or afforestation, while most of Southern Tall Grassveld had remained as grassland. For untransformed sites sampled in 1996, the composition of communally and commercially grazed land differed distinctly, although differences depended on an altitudinal gradient reflecting water availability. Sites under communal grazing supported a higher proportion of short-lived, perennial grass species, often of poor grazing value. From measurement of the extent of compositional change of each site, commercially grazed sites showed no consistent pattern of change, and the average extent of change was small. By contrast, communally grazed sites had on average changed considerably, although the direction of change had depended on the physical environment. Basal cover increased with altitude, with that of commercial rangeland consistently 5% higher than that of communal rangeland. Notwithstanding sampling problems of accurate relocation of his plots and adequately matching his subjective method of data collection, Acocks' data has provided an invaluable opportunity for examining vegetation change over an appropriate time scale for vegetation comprised of perennial plants.