Harmonisation and standardisation in multi-national environmental statistics - Mission impossible?

Multi-national statistics are frequently based on data, which originate fro m national surveys. The systems of nomenclature applied for key attributes often show national differences. Different error sources which are incorpor ated in multi-national statistics are discussed. The paper presents approac hes for harmonisation and standardisation of multi-national environmental s tatistics and gives examples from the forestry sector. The effect of differ ences of national forest area estimates on multi-national figures is quanti fied. An example from forest health surveys is presented that shows the imp act of different interpretation and application of the attribute "crown tra nsparency" that is already harmonised on the European level.