SIMULATING COMPETITION BETWEEN PLANTS USING MATHEMATICAL MODELS AND THE PROSPECT OF PREDICTING MARKETABLE YIELD

The many models that have been published to describe the competitive interactions between plants can be classified into four types based on the assumptions they make about the utilisation of resources by individual plants. The accuracy of the different assumptions of each type of model is described and none are shown to be without defect. The potential of these models is explored by using one of them to predict the expected yield in various commercial diameter grades at five harvests using the observed weights at an early initial harvest. Although the differences between observed and predicted yield were statistically significant at all but one of the harvests, they were sufficiently small to be commercially unimportant. Hence, the models developed by ecologists and biometricians to describe competition between plants might be adapted to be management aids for predicting yields in size grades in commercial crops.