AN UNCONVENTIONAL APPROACH TO TIMBER YIELD REGULATION FOR MULTI-AGED,MULTISPECIES FORESTS .2. APPLICATION TO A SOUTH-AFRICAN FOREST

The development and implementation of the senility criteria yield regu lation system to the multi-aged, multispecies forests of the southern Cape, South Africa, is described. The described yield regulation syste m aims to maximise the sustainable yield with minimised artificial imp act on the ecology and minimised managerial input. The felling cycle i s 10 years, which is still considered compatible with the prevailing n atural disturbance regime. Harvestable trees are not defined by minimu m harvestable diameters, but according to signs of senility or reduced remaining life expectancy (e.g. percentage crown dieback or base rot) . These criteria are determined for canopy species in accordance with species-proportional turnover rates. The gross increment of the stand is thus realised as harvest through periodic mortality preemption by h arvesting those trees which have reached a defined level of senility o r reduced life expectancy. Advantageous characteristics of the senilit y criteria yield regulation system relate to guaranteed sustainability , compatibility with nature conservation aims, optimal productivity an d managerial simplicity and flexibility. The potential of the system f or wider application is discussed.