Tree loss in the Gonarezhou National Park (Zimbabwe) between 1970 and 1983

Photopanoramas were used to study tree loss in the Gonarezhou National Park, Zimbabwe, between 1970 and 1983. The tree population declined, because of low recruitment and the loss of trees at 30·1% in 13 years with nearly 2·3% per annum at panorama points not close to water. There is an obvious but not simple relationship between tree mortality rate and temporal changes in elephant density. The association between elephant density and tree mortality is more evident in the 1977–1983 period when, by coincidence, excessive woodland destruction and elephant densities increased, and, in the same period, loss rates were probably exacerbated by dry spells. The main factors influencing tree loss are probably elephant density, fire and droughts. Because fire is probably a secondary factor in the consumption of woody vegetation, elephant density and drought are probably the main factors that influence tree mortality. Other environmental factors that can influence conditions in the Park are highlighted.