The impact of slash management, fertilisation and vegetation management on Pinus elliottii pulpwood growth and rotation-end yield

Abstract

Intensive silviculture (re-establishment) is practised within South African plantations to increase the potential productivity per unit area. Rotation-end productivity benefits are not well documented to support intensive inputs. A trial investigating rotation-end (17 years) impacts of slash management (clear, single and double slash loads), fertilisation (fertiliser applied versus no fertiliser applied) and vegetation management (none versus continuous weeding) was implemented on Pinus elliottii grown in Mpumalanga, South Africa. Competitive vegetation cover abundance and biomass, soil and foliar nutrients, and tree survival, growth and uniformity were recorded. The biomass sampled indicated a relationship between slash management and fertilisation with the vegetation biomass highest within the treatments where slash was cleared in combination with fertiliser application (4 398.7 kg ha−1) and within double slash treatments in combination with no fertiliser application (4 698.0 kg ha−1). Of all the main factors, only vegetation management significantly improved tree survival and growth (height, Dbh, basal area and volume) at rotation-end. Vegetation management improved survival by 9.4%, resulting in 67.5 m3 ha−1 more volume than in treatments where no vegetation management was carried out post-planting. This trial has highlighted the importance of vegetation management on rotation-end P. elliottii productivity.