Above Ground Food Resources and Herbivory in a Beech Forest Ecosystem

Abstract

In a 90 yr old beech stand the apparent beech leaf consumption 1967-1974 ranged from 7-20% (average 12.3%). Phyllophages actually removed 3-9% (average 5.7%) of leaf area index (LAI) - an average of about 9 g m-2 yr-1 (dry wt) of beech leaves (about 180 kJ m-2 yr-1), corresponding to 2-5% (average 3%) of annual leaf production and about 4% of available food. Due to wasteful feeding, average consumption of phyllophages on beech was only about 145 kJ m-2 yr-1. Leaves and mast were the above ground components of beech trees mainly attacked by herbivorous insects. Beech net assimilation was only insignificantly reduced by leaf consumption. Insect herbivory on beech represented 0.7-0.8% of beech net primary production; above ground insect herbivory in the beech forest ecosystem was < 1% of total above ground net primary production. Aspects of selective feeding of herbivores and the general role of phyllophages as primary consumers, secondary producers and regulators in the beech forest ecosystem are discussed.