Survival and growth of tree seedlings in relation to changes in the ground flora during natural regeneration of an oak shelterwood

Abstract

The development of the ground flora, and survival and height growth of tree seedlings, were observed annually over the 5-year period following a mast year in an oak woodland in southern England. After removal of the coppice understorey and thinning of the tree-canopy to leave 60-70 per cent cover there was a rapid development of the ground flora which was dominated throughout by Rubus fruticosus (bramble), although the frequency and amount of Pteridium aquilinum (bracken) increased with time. More than 10 woody species regenerated but only three, Quercus robur (oak), Fraxinus excelsior (ash) and Betula pendula (birch), were found in substantial amounts. Many birch and Corylus avellana (hazel) seedlings grew sufficiently well to emerge above the bramble and bracken; in contrast, after 2 years few oak and ash were taller than the bramble and none were taller than the bracken. The number of oak and ash seedlings was positively related to the number and proximity of parent trees. There were no consistent relationships between decreases in the sizes of the seedling populations and the type, amount and height of vegetation. The size of seedling populations generally declined with time with annual reductions varying from 0 to 90 per cent depending on species and year; for most of the study, oak and ash populations fell by 40-50 per cent each year. There were some significant relationships between seedling height and site characteristics but these were inconsistent, varying between tree species and year. Results are discussed in relation to the natural regeneration of oak. © Institute of Chartered Foresters, 2005.