Forest production efficiency increases with growth temperature

Abstract

Introductory paragraphWe present a global analysis of the relationship of forest production efficiency (FPE) to stand age and climate, based on a large compilation of data on gross primary production and either biomass production or net primary production. FPE is important for both forest production and atmospheric carbon dioxide uptake. Earlier findings – FPE declining with age – are supported by this analysis. However, FPE also increases with absolute latitude, precipitation and (all else equal) with temperature. The temperature effect is opposite to what would be expected based on the short-term physiological response of respiration rates to temperature. It implies top-down regulation of forest carbon loss, perhaps reflecting the higher carbon costs of nutrient acquisition in colder climates. Current ecosystem models do not reproduce this phenomenon. They consistently predict lower FPE in warmer climates, and are therefore likely to overestimate carbon losses in a warming climate.

Feasibility of enhancing carbon sequestration and stock capacity in temperate and boreal European forests via changes to management regimes

“…Given that the European forested area is composed of a mix of differing-aged stands, and since forest C cycle processes may respond differently to climate factors at different ages (e.g. Collalti and Prentice, 2019;Collalti et al, 2020b;Huber et al, 2018Huber et al, , 2020Migliavacca et al, 2021), we developed a Composite Forest Matrix (CFM) consisting of a mixture of stands of different age, structure and associated biomass. Starting from the real stands, we generated a prescribed number of virtual stands in order to obtain representative model outputs of a larger set of different age-classes (with their associated forest attributes) to cover an entire rotation period (~140 years, depending on species), similar to the approach in in Bohn and Huth (2017).…”

“…Net primary productivity can be a good proxy for forest carbon sink processes (Sha et al, 2022), and the net biomass input to forest ecosystems (Trotsiuk et al, 2020), with decomposition (decay, or heterotrophic respiration) processes representing the active carbon source process. Net primary production is a dynamic balance between photosynthesis and plant respiration, which respond separately and/or in combination to a range of climatic factors and, in managed forests, to management practices (Collalti et al, 2020a;2020b). These age-dependent responses are generally not prone to in situ quantification over long periods, especially for climate change issues, hence raising the need for process-based modeling.…”