BIOMASS, DECOMPOSITION AND NUTRIENT RELEASE OF VACCINIUM-MYRTILLUS LEAF-LITTER IN 4 FOREST STANDS

Biomass and nutrient transfer (N, P, K, Ca, Mg) of bilberry (Vaccinium myrtillus L.) leaf litter fall, as well as decomposition and nutrient release. were studied in four mature forest stands situated in Centra l and South Sweden. Bilberry leaf litter fall amounted to between 33 a nd 55 kg ha-1 yr-1 in the four stands. Only minor differences between sites were noted for litter concentrations of N, P and Ca, whereas K a nd Mg showed somewhat larger variability. Relative amounts of the five nutrient elements in the litter fall were generally in the order N > Ca > K > Mg > P. The amounts of nutrients returned to the forest floor by the annual leaf litter fall in the stands ranged from 0.4 to 0.8 k g ha-1 for N, 0.4 to 0.6 kg ha-1 for Ca, 0.2 to 0.7 kg ha-1 for K, 0.1 to 0.2 kg ha-1 for Mg and 0.04 to 0.08 kg ha-1 for P. The decompositi on of the local bilberry leaf litter was followed by means of litterba gs during three years. At all sites there was an extremely rapid mass loss from the litter (between 45% and 54%) during the first four to fi ve months of decomposition. After this initial phase, the decompositio n rates decreased markedly and after three years the accumulated mass losses of the litters varied between 64% and 78% at the studied sites. After two and three years of decomposition, three of the sites exhibi ted almost similar litter mass losses whereas at the fourth site the l itter was decomposed to a significantly lower degree. The pattern of n utrient release from the decomposing bilberry leaf litter differed som ewhat from site to site. Minor differences were, however, noted for P, Ca and Mg while N and K were more strongly retained in the litter at one of the sites.