1) Asian river 2) European watercourse 3) European waterway 4) European river 5) Forest 6) River in Russia 7) River in Europe 8) River of Russia 9) River of Asia 10) River in Asia 11) Russian watercourse 12) Russian waterway 13) Russian river 14) Silva 15) Timber 16) Timberland 17) Watercourse in Europe Found on https://www.crosswordclues.com/clue/sylva
Syl'va noun ; plural Sylvæ . [ Latin sylva , better silva , a wood. See Silva .] (Botany) Same as Silva . Found on http://www.encyclo.co.uk/webster/S/262