Groei en productie van fijnspar in Nederland

From 1951 to 1989 growth and yield research was done on Norway spruce in the Nether-lands. This includes studies by Becking and by the Dorschkamp/IBN research institute. Together with the permanent sample plots from the timber prognosis system HOSP, all this comprises a dataset of 116 plots with 388 recordings. For the development of top height htop with age t Cieszewski’s model with site index h50 and 3 additional parameters fitted best. The diameter development up to stand height of 7 m was best described with a Gompertz function based on htop and initial density N0. The basal area increment iG was best described by a power function based on htop, age and S%. For S% > 14.7 the basal area increment drops non-linear with S%. Year of recording and site index were not significant. The effect of thinning on the diameter after thinning was modelled with a modified La Bastide-Faber model. With all models together, a stand projection model was constructed, which de-scribes the measured stand development reasonably well. The model was used to construct yield tables with five site classes and five thinning intensities.