Inter- and intra-site variation in the fruiting of common beech (Fagus sylvatica L.) in England over a twenty two year period (1980-2001)

摘要

This study of annual production of mast by the common beech (Fagus sylvatica) in England has now continued for twenty two years; it will be further extended in order to assess long term regional and temporal variation of masting in this species. During this period, beech mast has been sampled from approximately 100 trees by 7-minute samples collected from the ground. Aerial samples have also been collected from low-growing branches. The sites concerned varied from closed canopy beechwood to shelterbelts, avenues and isolated trees in parks. Production of full seed varies greatly from year to year. Regional variation is much less, but over the period the northern trees have produced on average fewer full nuts but rather more empty and total nuts.Good masting occurred in 1980, 1982, 1984, 1987, 1990, 1995, 1997 and 2000: in these years at least one year of very poor masting normally followed. No full mast was found in 1981 and singularly little in 1991 and 2001. All trees produce empty pericarpsas well as full mast, especially on lower or shaded branches. The proportion of full nuts consumed or damaged by the moth Cydia fagiglandana, birds and small mammals, in English sites, can become significant in non-mast years.