SUMMARY

This study of the effects of liming and ammonium-sulfate fertilization on leaf phenology and leaf characteristics was part of an ecosystem research project at the site of the former IBP Solling Project on the effects of soil acidification on soil processes and tree physiology in a European beech (Fagus sylvatica) forest.  Beech trees fertilized with ammonium-sulfate showed delayed leafing-out in spring, while trees fertilized with lime showed a delay in the onset of leaf fall in fall.  Trees in both fertilization treatments had higher specific leaf weights and higher chlorophyll contents of sun leaves than the control treatment.  Trees fertilized with lime lost a higher percentage of their leaf area (18.2%) to phyllophageous insects, primarily to Chimabacce fagella, than trees fertilized with ammonium sulfate (14.4%) and control trees (13.0%).  After leafing out, the leaf area index and the average leaf size of trees fertilized with lime (6.3) exceeded that of trees fertilized with ammonium sulfate (5.6) and the control (5.8), but the differences between the treatments in the loss of leaf area to herbivores caused the leaf are index in all treatments to be similar at the end of the growing season (LAI » 5).