Evaluation of a bracken (Pteridium aquilinum (L) Kuhn) growth model in predicting the effects of control strategies across a range of climatic zones in Great Britain

A nationwide bracken control experiment provided data over a three-year period for testing the accuracy of a bracken growth model (BRACON). Objective assessments of model validity identified the model as a reasonably accurate predictor of bracken stand dynamics given the range of environmental conditions currently prevailing in Great Britain, in relation to (1) cutting regimes and (2) spraying asulam. Ranking of treatment efficacy at individual sites was closely reflected in model predictions. Predicted response of the rhizome system to cutting treatments underestimated bracken resilience. Failure to consider the consequences of frond regrowth in the latter portion of the growing season as a means to offsetting energy loss was identified as a potential explanation for this discrepancy. The role of the model as a practical management tool is discussed with particular reference to relating model predictions, based upon generalised environmental data (40km x 40km grid cells), to bracken management at individual sites.