IMIS - Marine Onderzoeksgroepen

The Level II plots make part of a European monitoring network (ICP-Forests). Monitoring data collected in all the plots (11) include: 1) dendrometric inventory (species, diameter and height of all the trees with a diameter >=5cm) - conducted every 5 years, plus diameter of 20 trees per plot from measuring bands every year; 2) crown condition assessment (colouring and loss of leaves or needles) - conducted yearly; damage (stem, roots, branches, leaves or needles) - conducted yearly; 3) ground vegetation uptake (cover per species for moss layer, herb layer, shrub layer and tree layer) - conducted every 5 years; leaf or needle analysis (from 5 selected trees in each plot) - chemical analysis every 2 years; physico-chemical soil properties - conducted every 10 years. Additional monitoring data collected in the 5 core plots include: 1) throughfall deposition (10 collectors below canopy) - volume and chemical analysis halfmonthly; 2) deposition outside the forest (4 collectors in the open field) - volume and chemical analysis halfmonthly; 3) stemflow (3-5 collectors around beech trees in the 3 plots dominated by broadleaves) - volume and chemical analysis halfmonthly; 4) humus water (4-6 lysimeters per plot) - volume and chemical analysis halfmonthly; 5) soil water (6 lysimeters in each horizont - A-, B- and C-horizont - on 3 different locations in the plot) - volume and chemical analysis halfmonthly; 6) ground water level (3 locations per plot) - measured halfmonthly; 7) soil moisture content (at 3 locations in each plot, 1 sensor per horizont or at fixed depths) - measured halfmonthly (old) to 6-hourly (new); litterfall (10 collectors per plot, split up in leaf/needle, woody material, fruits and seeds, budshells, rest) - biomass weighed monthly or halfmonthly in litterfall period, chemical analysis of a mixed sample for each fraction every year; LAI-measurements (based on hemispherical photographs and Licor 2000 measurements) - yearly; data of a wet-only sampler in 1 plot - volume and chemical analysis halfmonthly; phenology (data from 20 trees in each plot) - followed up seasonally. The Level I plots also make part of the ICP-forests monitoring network. In these 72 plots the vitality (damage on stem, roots, branches, leaves or needles) and crown condition of trees is estimated (colouring and loss of leaves or needles)