Growth potential ofEucalyptus globulussubsp.bicostataprovenances for the mid-altitude summer rainfall regions of South Africa

Abstract

In the tropics and Southern Hemisphere, plantation forestry of exotic tree species contributes substantially to the international paper and pulp industry. The most widely planted trees are species of Pinus, Eucalyptus and Acacia (Wingfield et al. 2002). In South Africa, Eucalyptus species comprise approximately 39% of the 1 333 562 ha of plantation forestry (FES 2006).Eucalyptus species have been planted in South Africa for more than a century beginning with the planting of E. globulus in the Cape Colony in 1828, which soon stimulated interest in other members of the genus for new introductions (Poynton 1979). More recently, eucalypts have been used extensively for the production of sawtimber and pulp and paper (Swain and Jones 2004), stimulating wide-ranging tree improvement activities in South Africa. New species and provenances are regularly introduced into the country and evaluated for their potential use in the forestry industry .Eucalyptus plantations in South Africa are found over a wide range of different climatic zones, with the humid, warmer temperate and subtropical regions comprising an important part of this area. Traditionally, E. grandis has been the most extensively cultivated hardwood species in these regions because of this species' rapid growth and acceptable wood properties (Poynton 1979). During the last two decades, however, commercial forestry in South Africa has expanded into mid-altitude summer-rainfall sites that are drier and warmer, or drier and colder, than so-called traditional forestry sites. These areas are not suitable for optimum growth of E. grandis and are generally referred to as 'low productivity' sites. The mean annual temperatures (MATs) of less than 18 °C and altitudes above 1 050-1 300 m, depending on latitude, are not suited to the planting of E. grandis (Swain and Gardner 2003a), as this species displays extensive susceptibility to drought-and cold-induced mortality (Darrow 1983). These mid-altitude sites are also not suited to the growth of E. nitens provenances that usually perform well at altitudes greater than 1 350 m, but do not grow well on these lower-altitude sites.Better-performing and better-adapted species and provenances are therefore required for sites too low for Eucalyptus grandis is cultivated extensively in the humid, warmer temperate and subtropical regions in South Africa. With forestry expanding into mid-altitude drier and warmer, or drier and colder, sites the search to identify reasonably well-performing species/provenances for such 'low productivity' sites has extended to summer-rainfall provenances of E. globulus subsp. bicostata, which is closely related to E. globulus, a species known to have superior kraft pulping. Seed from New South Wales, Australia, provenances Narrow Neck Ridge, Nullo Mountain (West) and Nullo Mountain (North) was established in provenance/progeny trials on four sites in South Africa (Windy Gap, Enon, Petrusvlei and Speenkoppies). Eucalyptus globulus and E. globulus subsp. maidenii were the internal controls. Trials were p...

Comparative performance of Eucalyptus bicostata, E. globulus, E. maidenii and E. pseudoglobulus on three northern New Zealand sites

“…The most northern E. bicostata provenance (Wollemi) in the present study occurred in a uniform rainfall zone, and displayed the best growth rate and foliage health of the seven E. bicostata provenences tested in the New Zealand test sites. This result is similar to the findings of (Komakech et al 2009), although the causality of this association remains to be demonstrated. The superior growth of E. maidenii found in this study compared with the other three blue gum species reflects the findings of (Shelbourne et al 2002) from longerterm large-plot comparisons with E. globulus.…”

“…However, different specific rankings have been reported from tests in warmer climates with more uniform seasonal distribution of rainfall. These include: anecdotal reports from central Africa and southern China (Eldridge et al, 1993); and formal comparisons among the species in northern New Zealand (Low & Shelbourne, 1999) and South Africa (Komakech et al, 2009). When compared in ex-situ species comparison tests, the relative performance of these species is expected to be related to the fit between the environmental parameters of the collection and test sites, and such relationships have been considered in planning introduction trials (e.g.…”

Genetic characterisation of a Eucalyptus nitens base breeding population in South Africa

“…This was also found in a South African trial series of E. globulus subsp. bicostata, where susceptible provenances were less infected at 30 months at two sites with lower rainfall (≤ 900 mm) than sites with higher rainfall (> 950 mm) (Komakech et al 2009).…”

“…Other authors have found this to be the case in E. nitens (Lundquist andPurnell 1987, Hunter et al 2004) and in E. globulus subsp. bicostata (Komakech et al 2009). In Australia, the Victorian provenances are tending towards a winter rainfall maximum with a drier summer and it is interesting that, of the sites in this South African trial series, the disease did not appear to be as prevalent at the Helvetia site, which has slightly lower rainfall than the other sites.…”

Correspondence of Loblolly Pine Response for Fusiform Rust Disease from Local and Wide-Ranging Tests in the Southern United States

“…The ratio in Equation 5 of family variance components over the sum of the family and family by site interaction variance has been used commonly to quantify the level of genotype by environment interaction in progeny trials (Burdon 1977, Yamada 1962. The type B correlation coefficient gives a general prediction of importance for interaction terms, in which a value less than 0.67 suggests that family by test site (GϫE) interactions could be considerable and warrant closer analysis to understand the underlying causes (Burdon 1977, Komakech 2009, Shelbourne 1972). …”