Lodgepole pine in Iceland: biomass gains cannot be interpreted without ecological costs. Response to Riege et al.

Abstract

We respond to Riege et al. (New For 56:68, 2025), who present valuable new data on early biomass accumulation by lodgepole pine (Pinus contorta) in Iceland. We argue that this finding cannot be evaluated without considering the well-documented ecological impacts of the species in this environment. In Iceland, P. contorta is already spreading rapidly beyond plantations, reducing vascular plant diversity and altering native sub-Arctic habitats. Iceland’s open lowlands are globally important biodiversity systems, particularly for ground-nesting waders, and are not “unused space” for carbon farming. Further, experience from other regions shows that long-term control of non-native conifers is difficult and costly. We therefore highlight that benefits (biomass gain) and risks (ecological impacts) must be assessed jointly. A balanced evaluation of P. contorta in Iceland requires integrating both dimensions.