INSTYTUT DENDROLOGII

Abstract: All yew plants in the Kórnik Arboretum have been plotted onto maps of individual sectors and analysed with respect to location category ("near trunk", "under canopy", "in the open"), size (assumed to reflect age), genus of tree associated with in the "near trunk" category and environmental factors characterising the respective Arboretum sectors. There is practically no regeneration "in the open" (0.2%), most of it 82.5% is "under canopy" and only 17.3% "near the trunk". It is assumed that thrushes (Turdidae) are primarily responsible for regeneration in the under canopy category (endozoochoria) and nuthatches (Sitta europea L.) in the near trunk category (synzoochoria). Under canopy regeneration exists in all size classes while near the trunk there is a distinct decline in the number of yew plants with increase in size (age) suggesting that conditions for further development there are less favourable. Nutchatches disperse yew seeds in the vicinity of mother plants, for cleaning them preferring trees to shrubs and particularly trees with smooth bark trunks (Fagus, Carpinus), however yew survival near the trunk is better under conifers. Thrushes disperse yew seed over wider areas. Survival of yews is best under loose canopies, in moderate shade, on drier well draining, low pH, soils.

Additional key words: endozoochoria, synzoochoria, Sitta europea, Turdidae, seed dispersal