The role of nitrogen in declining scots pine forests (Pinus sylvestris) in the lowland of East Germany

Over the last decade, N inputs in pine ecosystems on the lowland of the former GDR have clearly increased. Agriculture plays a special role as a NH_x emitter, because the whole lowland is covered with a network of large livestock farms. High N inputs cause an overnutrition of the pine stands with N, an accumulation of N in the soils, and as a consequence of the ensuing eutrophication, a drastic modification of the ground vegetation with a luxuriant growth of weeds and shrubs or of the vital herbaceous cover. The fine root quantity is reduced, also the mycorrhiza and the growth of pine. In many cases pine stands show a dramatical decrease of Mg nutrition. Finally, the limited range of silvicultural options is discussed, which are available to limit the progress of damage.