Riparian Forest in the Danube Delta, romania Big willows, alder and ash trees form a riparian forest along the channels Only during September large parts of the Delta dry out, high water marks on the trees are still showing the water level during the sp. Riparian Forest in the Danube Delta, romania Big willows, alder and ash trees form a riparian forest along the channels Only during September large parts of the Delta dry out, high water marks on the trees are still showing the water level d