L-DONAX, a growth model of the invasive weed species, Arundo donax L.

Arundo donax L. is a perennial reed and is an invasive weed of riparian systems in North America. A structural model (L-DONAX) of the species was constructed using L-system modelling in order to assist in understanding and demonstrating the complexities of the plant's development and structure. The model produces a realistic number of plant components from a single rhizome segment over the course of the first year of growth, using empirical relationships derived from outdoor experiments. Biomass production is also simulated, through the use of relationships found between aerial plant portion sizes and masses. L-DONAX demonstrates that control of A. donax clumps is likely to require more than annual biomass removal, due to the bulk of biomass being present underground, and the ability of remaining rhizome or stem segments to produce large clumps quickly. The model extrapolates to years of growth beyond the first, but is found to require some re-parameterisation to improve accuracy.