Survivorship of spekboom (Portulacaria afra) planted within the Subtropical Thicket Restoration Programme (with Corrigendum)

Abstract

Through the Subtropical Thicket Restoration Programme (STRP), about 21.5 million cuttings of spekboom (Portulacaria afra) were planted over the period 2004–2016 in the Addo Elephant National Park, Great Fish River Nature Reserve and the Baviaanskloof Nature Reserve. This planting includes a large experiment of 330 quarterhectare plots in which 14 different planting treatments were used.1 These experimental plots, known as the ‘thicketwide plots’, comprised 200 000 cuttings, with the remaining 21.3 million cuttings planted out in what were called the ‘large-scale plantings’. Some of the large-scale plantings were replanted with cuttings – a procedure referred to as blanking. The positioning and number of cuttings used in each blanking operation was not recorded and consequently the surviving cuttings in any particular landscape within the large-scale plantings cannot be aged accurately. Notwithstanding the limitation of many sites in the large-scale plantings made up of cuttings planted in different years, we saw value in monitoring survivorship of cuttings in random plots within the large-scale plantings, simply to determine the likely outcomes of the South African government’s investment in planting 21.5 million cuttings over the past 12 years.