Parasite dynamics of Viscum album L. in Austrian black pine stands in the Saignon watershed (southwestern Alps).

By mapping the infestation enlargement and counting the number of mistletoe s implanted yearly on 30 Austrian black pine trees about 100 years old, the infestation dynamics is spatially (landscape, tree architecture) and tempo rally studied. It starts from the trees located along the paths followed to enter the watershed by the main vector of mistletoe dispersal, i.e. thrush es (Turdus viscivorus). For highly infested trees, the infestation presents a pluriannual cycle, starting at the end of the 1970s and reaching its max imum about 10 to 15 years later. The medium term effect on toes, on the on- going process of forest restoration and the silvicultural methods to preven t mistletoe are discussed through the example of the Saignon watershed. (C) Inra/Elsevier, Paris.