Cold damage to woody plants in the Sourish Mixed Bushveld.

Abstract

An incident of damage to woody plants by cold in Sourish Mixed Bushveld was investigated. Woody plants in eight paddocks which were subjected to long-term grazing treatments and which gave rise to different tree densities, were examined. The most common form of damage was top kill, and these plants subsequently coppiced from the base. Four woody species, namely Dichrostachys cinerea (the dominant woody species in the area), Acacia nilotica, A. gerrardii and A. robusta were severely damaged by the cold. The greatest effect was on trees in a certain height range; 1, 0-3, 0 m in the case of D. cinerea and 0, 5-2.0 m in the case of the Acacia species. There was a negative curvilinear relationship between the number of trees larger than 2, 0 m per hectare and the percentage damage. In paddocks where the tree density was relatively low the number of tree equivalents (equivalents of a tree 1, 5 m high) was reduced by as much as 30%.

Keywords: acacia gerrardii; acacia nilotica; acacia robusta; afrikaans; coppice growth; damage; density; dichrostachys cinerea; grazing treatments; mixed bushveld; sourish mixed bushveld; south africa; towoomba research station; tree density; tree equivalents; trees; woody plants; woody species