Read an interview with Division 4 Coordinator Jean-Luc Peyron of the Public Interest Group (GIP) on Forest Ecosystems (ECOFOR), France, about the work in IUFRO Division 4 and the All-Division Meeting at the IUFRO 125th Anniversary Congress. The research range of Division 4 is rather broad, but it is consistent with the needs of policy makers and forest practitioners. For the Freiburg Congress, Division 4 organized more than 20 sessions. Technological developments give great opportunities to forest assessment, information systems, and the constitution and use of big data sets. Forest assessment measurements are made in order to predict the value of some variables and models are run to predict the evolution of those variables. There are uncertainties behind those results, especially when the prediction horizon is long. It is therefore important to produce models that integrate several scenarios and also take into account several management options. And that has to be communicated transparently to decision makers. Download the PDF: https://www.iufro.org/download/file/27614/6146/iufro2017-interwiew-d4_pdf/ Link to the IUFRO Blog: http://blog.iufro.org/2017/10/12/on-forest-assessment-modelling-and-manageme nt/ Learn more about IUFRO Division 4: https://www.iufro.org/science/divisions/division-4/ Watch this interview with Jean-Luc Peyron: https://youtu.be/q-_yFxiPpu0