The influence of species, tree improvement and cultural practices on rotation-end fibre production of Eucalyptus pulpwood plantations in South Africa

Growth and canopy traits affected by myrtle rust (Austropuccinia psidii Winter) in Eucalyptus grandis x Eucalyptus urophylla

“…However, disease occurrence damages leaf formation in the tree crown, allowing greater F I G U R E 4 Rust infestation scale according to the methodology proposed by Takahashi (2002) showing a higher duration and level of infection in control and curative treatments F I G U R E 5 Visual difference in growth between the control plot (without fungicide application) and the curative and preventive treatments at 11 months of age light incidence, also reported by Takahashi (2002). This leads to a greater weed infestation caused by a delay in canopy closure, which was more intense in the control plot, and may partially explain these results, due to the greater competition for water caused by grass infestation (Crous et al, 2019;Little et al, 2018;Vargas et al, 2018).…”

Productivity and water use of commercial forestry species and their potential impact on surface water resources in two forestry areas of KwaZulu-Natal, South Africa.

“…In a South African study by Gardner et al (2018) in warm temperate areas of KwaZulu-Natal, the basal area for E. dunnii, considered to be best suited to these climatic conditions, was 42 to 62% greater than alternative species (E. grandis and E. benthamii). Under similar conditions, a study by Crous et al (2019) reported a 10% higher survival, 6.4% greater basal area and 18.9% greater production in volume per ha by the firstchoice species (E. dunnii) relative to a species that was an alternative (E. grandis, E. smithii and E. macarthurii). In New Zealand, a study by Sims et al (1999) investigated the effect of site-species matching of nine Eucalyptus species and found that correctly matching species to site conditions produced a 15 to 20-fold increase in final yields.…”

“…1667 tree ha -1 ), while a low planting density is used for sawlog. Higher density of planting has been associated with higher total biomass, increased mean annual increment, decreased time to attain mean annual increment, however, with decreased total biomass per tree (Crous et al 2019). According to Stape et al (2001), there is no one optimum spacing, however, a spacing between 1200 and 1500 trees ha -1 , produced very little changes in final tree productivity.…”

“…For commercial forest plantations that are mechanically harvested, it is critical to be mindful that mechanised harvesting operations productivity improves with an increase in the average tree volume (Ramantswana et al 2013). Therefore, it is crucial to balance between planting density, harvesting costs and the mean tree size, as the density of planting that produces the high tree volume might not be the most financially viable option (Crous et al 2019).…”

“…Tree improvement is central to increasing plantation productivity per unit land area of commercial forestry species and have been implemented with success in many parts of the world, including Australia (Hamilton et al 2008), Portugal (Borralho et al 1992), Chile (Arnold et al 1991) and South Africa (Boreham and Pallet 2009, Swain et al 2015, Crous et al 2019.…”