CROWN EFFICIENCY OF OAK STANDARDS AS AFFECTED BY MISTLETOE AND COPPICE REMOVAL

Effects of mistletoe (Loranthus europaeus Jacq.) and coppice removal o n the efficiency of crown projection area and the growth of sessile oa k (Quercus petraea Liebl. ) standards were studied in a 2 x 2 factoria l experiment with nine replications. Four treatments were applied in 1 980: control, coppice removal only, mistletoe removal only and removal of both coppice and mistletoe. After 11 years, the basal area increme nt, the crown efficiency (basal area increment per square metre of cro wn projection area) and the crown projection area increment showed sta tistically significant interactions between initial crown size, coppic e removal and mistletoe removal. The basal area increment increased st rongly with increasing crown size, but crown efficiency was maintained at the same low threshold for all crown sizes when the coppice remain ed, regardless of whether mistletoe was removed or not. This constant crown efficiency may be attributed to a decrease in crown projection a rea of larger trees rather than to higher increments. The effect of co ppice removal was highest for small crowns and was independent of mist letoe removal. For larger crowns, the effect of coppice removal was mu ch more pronounced when mistletoe was also removed.