Stable forest carbon stocks support current assumption of biogenic carbon neutrality in the case of European-manufactured beverage cartons

This is the final version. Available on open access from Springer Verlag via the DOI in this recordPurpose: Life cycle assessments (LCAs) of forest-based products, such as beverage cartons, generally demonstrate lower greenhouse gas emissions than fossil fuel-based alternatives and often contain the implicit assumption that removal of carbon dioxide (CO2) by a growing forest and emission of CO2at the end of a product’s life cancel each other out such that the net emission is zero. This study aims to test the validity of this assumption of biogenic CO2neutrality in relation to beverage cartons by examining whether carbon stocks of the source forests are stable. The fact that over 95 % of the cartonboard used in their manufacture is sourced from the boreal forests of Sweden and Finland provides a scenario with a straightforward relationship between forest and product thus avoiding issues surrounding the complexities of global supply chains. Methods: The reviewed LCAs conclude that beverage cartons have lower greenhouse gas emissions than alternatives, although non-forest-derived components such as plastic caps and aluminium laminate often contribute disproportionately to those emissions. We discuss issues surrounding the assumption of biogenic CO2neutrality and explore the factors that influence carbon stocks in boreal forests that supply much of the raw material for beverage cartons. Results and discussion: An analysis of published rates of carbon sequestration in the managed forests of Finland and Sweden reveals that forest carbon is stable under current harvest rates. This lends support to the assumption of biogenic CO2neutrality in the case of beverage cartons produced from these forests. We conclude that greenhouse gas emissions would not change if an LCA included forest carbon. However, future forest dynamics and thus carbon stocks are predicted to alter in response to climate change, for example, which will have knock on effects for greenhouse gas emissions from packaging derived from forests. Conclusions: This review combines current thinking on inclusion of forest carbon in LCAs with an analysis of issues that will influence carbon stocks in managed forests. Although current assumptions of biogenic CO2neutrality are valid in the case of European-manufactured beverage cartons, we argue that this assumption needs to be explicitly addressed in LCAs. While there is no accepted methodology for integrating biogenic forest carbon uptake into LCA, our assessment of current trends in forest carbon stocks allows for assumptions of biogenic CO2neutrality to be tested, although our approach may not be practical for more complex supply chains.This paper is based on research funded by The Alliance for Beverage Cartons and the Environment (ACE) UK and the Earthwatch Institute

Enhanced woody biomass production in a mature temperate forest under elevated CO2

This is the final version. Available from Nature Research via the DOI in this record. Data availability: All data are publicly available without restriction at Dryad (https://datadryad.org/stash) at https://doi.org/10.5061/dryad.z612jm6jw (ref. 54). Biological samples (leaf litter, tree cores) were collected at the BIFoR research site (52.801° N, 2.301° W) and are archived at the University of Birmingham.Code availability: Quantitative structure models and calculation of tree volume from TLS data (QSMs) used the open-source software optQSM (https://github.com/apburt/optqsm) and TreeQSM v.2.4.1 (https://github.com/InverseTampere/TreeQSM).Enhanced CO2 assimilation by forests as atmospheric CO2 concentration rises could slow the rate of CO2 increase if the assimilated carbon is allocated to long-lived biomass. Experiments in young tree plantations support a CO2 fertilization effect as atmospheric CO2 continues to increase. Uncertainty exists, however, as to whether older, more mature forests retain the capacity to respond to elevated CO2. Here, aided by tree-ring analysis and canopy laser scanning, we show that a 180-year-old Quercus robur L. woodland in central England increased the production of woody biomass when exposed to free-air CO2 enrichment (FACE) for 7 years. Further, elevated CO2 increased exudation of carbon from fine roots into the soil with likely effects on nutrient cycles. The increase in tree growth and allocation to long-lived woody biomass demonstrated here substantiates the major role for mature temperate forests in climate change mitigation.Natural Environment Research Council (NERC)UK Research and InnovationJABBS foundationUniversity of BirminghamJohn Horseman Trus

Creating positive environmental impact through citizen science

Interest in citizen science is growing, including from governments and research funders. This interest is often driven by a desire for positive environmental impact, and the expectation that citizen science can deliver it by engaging the public and simultaneously collecting environmental data. Yet, in practice, there is often a gap between expected and realised impact. To close this gap, we need to better understand pathways to impact and what it takes to realise them. We articulate six key pathways through which citizen science can create positive environmental change: (1) environmental management; (2) evidence for policy; (3) behaviour change; (4) social network championing; (5) political advocacy; and (6) community action. We explore the project attributes likely to create impact through each of these pathways and show that there is an interplay between these project attributes and the needs and motivations of target participant groups. Exploring this interplay, we create a framework that articulates four citizen science approaches that create environmental impact in different ways: place-based community action; interest group investigation; captive learning research; and mass participation census

Driving factors behind litter decomposition and nutrient release at temperate forest edges

Forest edges have become important features in landscapes worldwide. Edges are exposed to a different microclimate and higher atmospheric nitrogen (N) deposition compared to forest interiors. It is, however, unclear how microclimate and elevated N deposition affect nutrient cycling at forest edges. We studied litter decomposition and release of N, phosphorus (P), total cations (TC) and C/N ratios during 18 months via the litterbag technique along edge-to-interior transects in two oak (Quercus robur L.) and two pine (Pinus nigra ssp. laricio Maire and ssp. nigra Arnold) stands in Belgium. Furthermore, the roles of edge conditions (microclimate, atmospheric deposition, soil fauna and soil physicochemical conditions), litter quality and edge decomposer community were investigated as underlying driving factors for litter decomposition. Litter of edge and interior was interchanged (focusing on the influence of edge conditions and litter quality) and placed in open-top chamber (OTC), which create an edge (warmer) microclimate. As the decomposer macrofauna was more abundant at the edge than in the interior, the OTCs were used to isolate the effects of warming versus soil fauna. Oak litter at the edge lost 87 and 37% more mass than litter in the interior. We demonstrated an edge effect on litter decomposition and nutrient release, caused by an interplay of edge conditions (atmospheric deposition of N and TC, soil pH and C/N ratio), litter quality and soil fauna. Consequently, edge effects must be accounted for when quantifying ecosystem processes, such as litter decomposition and nutrient cycling in fragmented landscapes