Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

A different approach to site evaluation and some preliminary results.

Abstract

A new approach towards site evaluation for exotic tree species with a limited and non-representative occurrence is described. In an area of the Transvaal with annual rainfall of 800-900 mm, trials of 12 eucalypt species and Acacia mearnsii as a control were planted on deep and shallow soils at sites of 1200, 1400 and 1600 m alt. Studies up to age 2 yr showed that E. smithii performed best of all eucalypts below 1500 m (mean annual temp. 15°C), but was overtaken at higher alt. by E. nitens and E. delegatensis and by more frost tolerant species such as E. macarthurii and E. viminalis on frost-prone sites. E. macarthurii showed high resistance to attack by Macrotermes spp., and E. dunnii, E. smithii and E. viminalis showed reasonable resistance. It was found that when all growth factors are adequate, the growth rates of most species are similar, irrespective of what the rates were previously. Even after 2 yr these experiments gave more information on site/species relationships than could be achieved by classical site evaluation techniques in limited and non-representative populations.