Assessing the growth of main European confiferous forests under a warmer climatic regime

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

Co-applicants : Department of Forest Inventory BFW (Austria)

Collaboration :

• Thomas Gschwantner, Klemens Schadauer (Dept. of Forest Inventory, BFW)
• Jean-Christophe Hervé (LIF, IGN)

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Context – Recent climatic warming questions how sustainable forest growth will be in the future, and whether some diversity in tree species responses would inform of their respective suitability for forest production function. Concern is raised for fast-growing coniferous species that significantly support forestry activities in Europe. Because some naturally grow in colder mountain/Nordic contexts and have been introduced in warmer hills and plains, or occupy more southern areas in Europe where water constraints may increase, their response is likely not uniform.

Objectives – Based on collaboration between French and Austrian research inventory teams, the objectives are 1) to investigate recent growth trends and anomalies of major European coniferous tree species present in oceanic, continental and mountain ranges in Europe, and representative of contrasting climatic niches, and 2) to study their relationships with climatic factors to infer their possible long-term effects on their behavior . Forest growth will be described at an annual resolution covering large forest domains, an original approach made possible by recent progress made in French and Austrian NFI programs.

Approach – Species to be studied will include Norway spruce, silver fir, Scots pine and European larch (in both countries) and maritime pine and Douglas fir in France only. These species will be studied in their natural and afforested and range sites, and within reference communities to accurately filter environment-driven growth signals. Using a statistical approach, annual growth chronologies of cumulated forest growth rates in regional domains will be developed, providing an unprecedented view of recent warmer climatic regime impacts (past 25 years). Second, the growth response of these tree species over wide climatic gradients will be inferred and modeled to extrapolate their future qualitative growth behavior.

Expected results and impacts  – The project will deliver an overview of recent growth trends in an extended set of European coniferous tree species, and will provide a substantial foundation for developing future indicators related to tree species and forest system performance, and tools to monitor how forests are impacted by climatic changes .