The influence of the 1991/92 drought on the woody vegetation of the Kruger National Park

Abstract

All observations and data related to the impact of the 1991/92 drought on the woody vegetation, excluding the riverine vegetation of major rivers, are summarised. This includes data from a visual estimate of damage from aerial photographs, surveys on selected sites, and general observations. Despite lower rainfall, the area north of the Olifants River (excluding the far-northern part) was less affected than the area south of it, suggesting that the woody vegetation in the north is more adapted to drought. A characteristic of the drought was the localised distribution pattern and variable intensity of damage to the same species in the same general area. Information on 31 species are presented briefly. Although a large number of woody species was to some extent damaged, when the woody vegetation is considered as a whole, the influence of the drought was not very severe

Temporal and spatial patterns in drought‐related tree dieback in Australian savanna

“…However, this study suggests that the model may underestimate either the magnitude of subsurface moisture de®cits during extreme drought or the sensitivity of savanna tree species. There is documentation of substantial drought-related tree dieback in Africa (Scholes 1985;Viljoen 1995;Tafangenyasha 1997) as well as Australia. Viljoen's (1995) study suggests substantial death for some species at some sites (i.e.…”

“…There is documentation of substantial drought-related tree dieback in Africa (Scholes 1985;Viljoen 1995;Tafangenyasha 1997) as well as Australia. Viljoen's (1995) study suggests substantial death for some species at some sites (i.e. 78% for Dichrostachys cinerea, 72% for Strychnos madagascariensis and 93% of Acacia tortilis) in Kruger National Park, South Africa.…”

“…Where drought has been included in tree±grass savanna function models there has been no reference to real data (Jeltsch et al 1996). The eect of extreme drought on tree cover has barely been studied in tropical savanna (Viljoen 1995). Opportunities to do so are rare because by their nature droughts occur at irregular intervals.…”

Die-back of kiaat (Pterocarpus angolensis) in southern Africa: a cause for concern?

“…The effects of this drought had also been noticed on trees in the nearby Kruger National Park (Viljoen 1995, Krynauw 1998. In particular, Viljoen (1995) found that although only 16% of trees greater than 8 m in height were dead at the Napi area in the Kruger National Park, 80% of the total tree population had less than 10% growth, based on assessments of coppice, a single living branch, or a stem or shoot sprouting from the roots, although even coppicing was poor. In the Pretoriuskop area, Viljoen (1995) noted that survival was considerably better and only 21% of the trees sampled had drought-induced damage of more than 50%.…”

“…In particular, Viljoen (1995) found that although only 16% of trees greater than 8 m in height were dead at the Napi area in the Kruger National Park, 80% of the total tree population had less than 10% growth, based on assessments of coppice, a single living branch, or a stem or shoot sprouting from the roots, although even coppicing was poor. In the Pretoriuskop area, Viljoen (1995) noted that survival was considerably better and only 21% of the trees sampled had drought-induced damage of more than 50%. In addition to the reports from the Kruger National Park and Mawewe, John Burrows (Buffelskloof Nature Reserve reserve manager, Lydenburg, pers.…”