N E W S & V I E W S • S E P T E M B E R 2 0 2 3 21 The El Niñio weather event occurs when the equatorial Pacific Ocean gets up to 3°C warmer than usual, and it normally has a global impact on weather patterns. El Niño has officially started and is expected to become strong by summer. This year’s event is predicted to be a big one, having a dramatic effect on weather patterns around the world. It’s likely to set new heat records, energise rainfall in South America, fuel drought in Africa, and disrupt the global economy. It may already be responsible for early-season heat waves in Asia and Europe this year resulting in record high global temperatures. New record daily global temperatures have already been set on three separate occasions. South Africa is a relatively dry country and even in the wetter regions (Forestry areas) water is generally the single most limiting factor to tree growth. It is therefore important to manage all timber compartments based on trying to reduce water stress on trees. This includes all aspects of Forest Management: from the initial choice of species to plant, to the implementation of silviculture operations and the protection of soils during harvesting and extraction. Soils are the reservoir that store water and nutrients to drive tree growth, they should be protected and enhanced at every opportunity! SITE-SPECIES MATCHING Soil, rainfall, temperature, and topographical information are considered when selecting a species suited to an area. Site species matching is particularly important on drought prone sites. Lessons learn from past dry periods include: • Soils with an Effective Rooting Depth (ERD) of less than 40 cm should not be planted (except for high rainfall mist-belt areas). Hydromorphic soils (wet) should not be planted. • In coastal areas (below 400m) plant hardy species or hybrids on marginal sites (C. henryi hybrids, E. grandis x E. longirosrata and some hardy E. grandis x E. urophylla hybrids). • On marginal mid-altitude sites plant A. mearnsii, E. dunnii or hardy hybrids. • Marginal sites between 1100m and 1400m can be planted to E. dunnii, E. badgensis (above 1200m). • High altitude marginal sites can be planted to E. badgensis. • Clonal hybrids of E. grandis can be deployed on marginal E. grandis sites but it is important to consult with the nursery supplying the material to ensure that you are planting a ‘drought hardy’ clone. • Black Wattle: Black wattle is a relatively drought hardy species and is often planted on shallow, El Niñio and management of plantations under drought conditions – Craig Norris, NCT’s Tree Farming Manager –
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