Are forest disturbances amplifying or canceling out climate change-induced productivity changes in European forests?

Abstract

Recent studies projecting future climate change impacts on forests mainly consider either the effects of climate change on productivity or on disturbances. However, productivity and disturbances are intrinsically linked because 1) disturbances directly affect forest productivity (e.g. via a reduction in leaf area, growing stock or resource-use efficiency), and 2) disturbance susceptibility is often coupled to a certain development phase of the forest with productivity determining the time a forest is in this specific phase of susceptibility. The objective of this paper is to provide an overview of forest productivity changes in different forest regions in Europe under climate change, and partition these changes into effects induced by climate change alone and by climate change and disturbances. We present projections of climate change impacts on forest productivity from state-of-the-art forest models that dynamically simulate forest productivity and the effects of the main European disturbance agents (fire, storm, insects), driven by the same climate scenario in seven forest case studies along a large climatic gradient throughout Europe. Our study shows that, in most cases, including disturbances in the simulations exaggerate ongoing productivity declines or cancel out productivity gains in response to climate change. In fewer cases, disturbances also increase productivity or buffer climate-change induced productivity losses, e.g. because low severity fires can alleviate resource competition and increase fertilization. Even though our results cannot simply be extrapolated to other types of forests and disturbances, we argue that it is necessary to interpret climate change-induced productivity and disturbance changes jointly to capture the full range of climate change impacts on forests and to plan adaptation measures.

More than the sum of its parts: how disturbance interactions shape forest dynamics under climate change

“…Further, we found the importance of climate on both mortality and carbon stocks was overestimated when disturbances were run separately, because running the disturbances concurrently dampens the climate change effect. This confirms work across a range of sites and models that illustrate that disturbances either dampen (Loehman et al 2017) or cancel out productivity gains due to climate change (Reyer et al 2017). Greater negative feedbacks under concurrent disturbances suggest that the typical approach to calibrating modeled disturbances separately may not be appropriate.…”

“…) or cancel out productivity gains due to climate change (Reyer et al. ). Greater negative feedbacks under concurrent disturbances suggest that the typical approach to calibrating modeled disturbances separately may not be appropriate.…”

Temporal and Spatial Change in Diameter Growth of Boreal Scots Pine, Norway Spruce, and Birch under Recent-Generation (CMIP5) Global Climate Model Projections for the 21st Century

“…This was not evident based on earlier impact studies employing climate data of the CMIP3 database. Climate change likely also increases abiotic and biotic damages (e.g., [57][58][59][60][61]), which may partially counteract the positive effects of climate change on forest growth and timber supply (e.g., [62,63]). However, we did not consider them in our study.…”

The Net Landscape Carbon Balance—Integrating terrestrial and aquatic carbon fluxes in a managed boreal forest landscape in Sweden

“…The underlying factors of these positive effects remain elusive, but have been suggested to include increases in temperature, nitrogen deposition, precipitation, and atmospheric CO 2 concentrations. Changing environmental conditions may, however, also create less favorable condition and hence counterbalance productivity gains (Hanewinkel, Cullmann, Schelhaas, Nabuurs, & Zimmermann, 2013;Reyer et al, 2017). As the boreal biome stores about one-third of the global terrestrial soil C, it provides an important interface of land-atmosphere exchanges of GHGs creating a feedback between climate and boreal ecosystems (Beer et al, 2010;Bonan, 2008;Gauthier, Bernier, Kuuluvainen, Shvidenko, & Schepaschenko, 2015).…”