Developing Dynamic Site Index Curves for European Beech (Fagus sylvatica L.) in Denmark

In base-age specific methodologies, assessment of base age and site index may be a problem when developing site curves from repeated measurements on permanent sample plot data. In most cases, such data will not contain measurements at any base age that is common for all the sample plots, and some sort of interpolation or even extrapolation would have to be applied to address this issue. Base-age invariant methodologies pose the desirable property of estimating the curves without prior arbitrary assumptions about values of the site indices. Presented here is the development of such base-age invariant site index curves for European beech (Fagus sylvatica L.) in Denmark, fitted to permanent sample plot data. The developed polymorphic dynamic site equations with variable asymptotes are based on the generalized algebraic difference approach, and the parameters of the model were estimated with correction for first-order serial correlation.