Maximum likelihood linear calibration of pollen spectra in terms of forest composition

Each taxon's pollen deposition rate is assumed to be an independent linear function of its abundance within a fixed distance of the depositional site. Pollen data are assumed to consist of relative counts, rather than estimates of absolute deposition rates. Different approximations lead to 2 alternative models relating pollen counts to relative tree abundances. Maximum likelihood estimates and standard deviations are obtained numerically for the parameters of both models. The models are illustrated and compared by using surface pollen data and forest inventory data from Wisconsin and Upper Michigan; the models explain 70-80% of the variance in the pollen data and give interpretable and congruent results.-from Authors