URBAN RIPARIAL AND FLOODPLAIN FORESTS TRANSECT IN THE CITY OF LJUBLJANA. The urban forest site consists of a riparian pine forest, floodplain hardwood forest and a meadow. It is located in the sub-urban part of Ljubljana, along the Sava river at 300 m above sea level. Bedrock material is glaciofluvial gravel and the soil was classified as Fluvisols (WRB 2007). Each part of this site consists of a 0.25 ha square plot. The urban riparian forest site is positioned on a river terrace, outside of the direct influence of the river water. It is composed of Pinus sylvestris L. in the upper canopy layer, and a mixture of deciduous tree species in the mid-story and lower canopy layer, such as Tilia cordata Mill., Quercus petraea (Mattuschka) Liebl. and Carpinus betulus L. The canopy cover is very loose, with a dense understorey. The thickness of the O horizon is 0 to 6 cm and the depth of the M horizon is 0 to 40 cm, with a sandy loam texture. The floodplain hardwood forest is located near the riparian pine forest, approximately 2 m above the Sava River terrace. It is composed of Acer pseudoplatanus L., Alnus incana (L.) Moench., Tilia cordata Mill., etc. Canopy cover is loose, with rather dense shrub and forest floor vegetation. This site is exposed to spontaneous spreading of invasive alien plant species due to frequent flooding. The thickness of the O horizon is 0 t to 4 cm and the depth of the M horizon was between 0 and 90 cm, with a clay-loam texture.