Forest management of fast-growing industrial wood plantations requires application of sound business principles and good forestry technology, to ensure a sustainable, value-adding and profitable wood supply is available, for the manufacture of diverse and globally competitive forest products. This is challenging from plantations that form part of a mosaic of land use and are part of a wider rural development.
Risk associated with crop production is probably the main limiting factor to increasing harvests from industrial wood plantations in South Africa, and the yield expectation associated with current silviculture practices is unlikely to be frequently attained in practice. Re-establishment is subject to considerable within-season variability in weather conditions. Periods of low rainfall, high temperature, hail, early and late season frost and extreme winter frost can reduce post-plant survival leading to replanting or the uncertain outcome from blanking operations.
Forest management decisions, ranging from strategic to operational scales, already require some type of site information in almost all instances. An improved understanding of site potential and using this to make more effective site-specific management decisions will be vital to plantation forestry facing uncertain future conditions. This focus area consists of a suite of projects intended to advance our capability to manage site potential.
Acacia mearnsii De Wild (black wattle) is an important forestry plantation species for tannin production and woodchip exports in South Africa, and breeding of this species is the key focus of the Acacia Tree Improvement project at the ICFR. Research to date has made significant improvements in bark yield, tannin content, tree volume, stem form and disease incidence (gummosis) during the first decades of the breeding programme.
Developing and deploying genetically improved planting stock remains one of the most effective single means of improving yield, reducing crop risk and obtaining more value from markets. Eucalypt tree improvement has been a key focus of the ICFR’s research for many years, specifically on breeding of the main commercial sub-tropical and temperate species into first domesticated generations. This work has largely been completed and published.