No adverse signs of the effect of environmental change on tree biomass in the Knysna forest during the 1990s

Midgley, J J; Seydack, A

No adverse signs of the effect of environmental change on tree biomass in the Knysna forest during the 1990s

Journal Article

2006

Journal Title

South African Journal of Science

Link to Journal

https://www.sajs.co.za/

Publisher

University of Cape Town

Department

Department of Biological Sciences

Faculty

Faculty of Science

Abstract

We analysed the growth of all trees greater than 10 cm diameter at breast height in 108 plots of 0.04 ha each in an unharvested nature reserve in the Knysna forest for the period 1991-2001. Gross growth rates (in-growth plus growth of survivors) of trees were extremely slow (<1%) and thus the forest is extremely sensitive to changes in mortality of large trees. Over the 10-year study period, total basal area and biomass increased by 2%, in part because overall stem density increased by 1.2%. Rainfall in the 1990s was slightly below the longterm mean for the study area. At this stage, therefore, the Knysna forest biomass is not showing a negative response to environmental change.