Changing use of species and hybrids in South African forest plantations

Abstract

South Africa has 1.2 million hectares of plantations developed progressively through the 20th century. These occur from 23° to 34°S, from near sea level to 2 000 m above sea level and in both Mediterranean winter rainfall and summer subtropical rainfall climates. Plantations supply pulp mills, sawmills, treated pole and mining timber production, and wattle tannin production. The diversity of sites and markets requires planting of a range of taxa of pine, eucalypt and wattle. A survey of planted area by taxa in South African forest plantations is reported and compared to statistics available from national annual reporting on the commercial timber resources in the country. The survey found a similar number of taxa are currently planted (15) as in the 1950s but only 6 of the earlier options remain in use. Changes have occurred in the last 30 years, with 40% of planted area in 2019 using options not available before 1990. From the 1990s, Eucalyptus grandis has been extensively replaced by eucalypt hybrids and E. dunnii and Pinus elliottii × P. caribaea var. hondurensis has become an important pine planting option. Over the past decade, E. nitens replacement with other existing frost tolerant eucalypt planting options has occurred, use of P. radiata has reduced and P. patula has been replaced on a significant scale with P. patula hybrids. Many of these changes have been to mitigate the impact of new pests and pathogens and, on lower productivity sites, periodic severe droughts. However, the new planting options also provide increased yields and have wood properties acceptable to the intended markets. Meeting all three criteria is likely to remain a requirement for successful introduction of future new planting options. The survey indicates a need to revise current national reporting requirements to better reflect use of species and hybrids in South African plantations.