Long-term Expansion of French Forests: Causal processes and Tools to support Sustainable Forest Management

PI : Jean-Daniel Bontemps (Laboratoire de l’Inventaire Forestier – LIF), IGN

Co-applicants :
Jean-Luc Dupouey (UMR INRA/UL 1137 Ecologie et Ecophysiologie Forestière – EEF)
Holger Wernsdörfer, AgroParisTech (UMR INRA/AgroParisTech 1092 Laboratoire d’Etude des Ressources Forêts-Bois – LERFoB)

Collaboration :
Jean-Michel Leban (INRA)


Context — After centuries of decrease, the forested area of developed countries has been increasing since the industrial revolution, a phenomenon known as ‘Forest Transition’. This unprecedented expansion in forest area and growing stock is widely attested in Europe, and in France. Developing macro-scale models of forest dynamics and deciphering the causes of forest expansion (natural afforestation, coppice conversion to high forests, plantation programs, felling regimes…) are therefore crucial issues to support future sustainable forest management on the larger scale.

Objectives — These include: 1) the development of macro-scale modelling tools of forest dynamics robust for extended conditions of forest management, 2) the analysis of major changes at play in the French forests over the 20th century from historical inventories and documentation, 3) the use of the forest dynamics model to decipher the past and current processes of forest expansion in France, as a baseline for assessing the development and availability of wood resources.

Approaches — Analyses will be based on 1) macro-scale forest modelling concepts covering forest growth, forest area dynamics and density-dependence processes, 2) modern National Forest Inventory (NFI) implemented in the 1960s, as forest sequences for model calibration and evaluation, 3) the first French forest statistics ‘Daubrée’ (1912), providing early information on forest composition and structure at the scale of administrative “Departements”. These sources will be used to evaluate forest changes between 1912 and contemporary NFI inventories, and for model initialization in a simulation analysis of the historical causes of forest expansion.

Expected results and impacts — This project will provide an overview of forest expansion after the forest transition in France, and a quantitative analysis of its historical drivers and associated forest types, as categories of importance for present and future sustainable forest management. It will further allow significant developments on a macro-scale forest model able to address current issues in forest policy.