Characterization of branch complexity by fractal analyses

The comparison between complexity in the sense of space occupancy (box-coun ting fractal dimension D-c and information dimension D-1) and heterogeneity in the sense of space distribution (average evenness index (J) over bar an d evenness variation coefficient J(CV)) were investigated in mathematical f ractal objects and natural branch structures. In general, increased fractal dimension was paired with low heterogeneity. Comparisons between branch ar chitecture in Anthyllis cytisoides under different slope exposure and grazi ng impact revealed that branches were more complex and more homogeneously d istributed for plants on northern exposures than southern, while grazing ha d no impact during a wet year. Developmental instability was also investiga ted by the statistical noise of the allometric relation between internode l ength and node order. In conclusion, our study demonstrated that fractal di mension of branch structure can be used to analyze the structural organizat ion of plants, especially if we consider not only fractal dimension but als o shoot distribution within the canopy (lacunarity). These indexes together with developmental instability analyses are good indicators of growth resp onses to the environment.