Joana Amaral Paulo

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

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.

Agroforestry systems of high nature and cultural value in Europe: provision of commercial goods and other ecosystem services

Land use systems that integrate woody vegetation with livestock and/or crops and are recognised for their biodiversity and cultural importance can be termed high nature and cultural value (HNCV) agroforestry. In this review, based on the literature and stakeholder knowledge, we describe the structure, components and management practices of ten contrasting HNCV agroforestry systems distributed across five European bioclimatic regions. We also compile and categorize the ecosystem services provided by these agroforestry systems, following the Common International Classification of Ecosystem Services. HNCV agroforestry in Europe generally enhances biodiversity and regulating ecosystem services relative to conventional agriculture and forestry. These systems can reduce fire risk, compared to conventional forestry, and can increase carbon sequestration, moderate the microclimate, and reduce soil erosion and nutrient leaching compared to conventional agriculture. However, some of the evidence is location specific and a better geographical coverage is needed to generalize patterns at broader scales. Although some traditional practices and products have been abandoned, many of the studied systems continue to provide multiple woody and non-woody plant products and high-quality food from livestock and game. Some of the cultural value of these systems can also be captured through tourism and local events. However there remains a continual challenge for farmers, landowners and society to fully translate the positive social and environmental impacts of HNCV agroforestry into market prices for the products and services.

How is agroforestry perceived in Europe? An assessment of positive and negative aspects by stakeholders

Whilst the benefits of agroforestry are widely recognised in tropical latitudes few studies have assessed how agroforestry is perceived in temperate latitudes. This study evaluates how stakeholders and key actors including farmers, landowners, agricultural advisors, researchers and environmentalists perceive the implementation and expansion of agroforestry in Europe. Meetings were held with 30 stakeholder groups covering different agroforestry systems in 2014 in eleven EU countries (Denmark, France, Germany, Greece, Hungary, Italy, Netherlands, Portugal, Spain, Sweden and the United Kingdom). In total 344 valid responses were received to a questionnaire where stakeholders were asked to rank the positive and negative aspects of implementing agroforestry in their region. Improved biodiversity and wildlife habitats, animal health and welfare, and landscape aesthetics were seen as the main positive aspects of agroforestry. By contrast, increased labour, complexity of work, management costs and administrative burden were seen as the most important negative aspects. Overall, improving the environmental value of agriculture was seen as the main benefit of agroforestry, whilst management and socio-economic issues were seen as the greatest barriers. The great variability in the opportunities and barriers of the systems suggests enhanced adoption of agroforestry across Europe will be most likely to occur with specific initiatives for each type of system.

A carbon footprint simulation model for the cork oak sector

In the present study, a simulation model for the calculation of the carbon footprint of the cork oak sector (CCFM) is developed for the first time. A life cycle approach is adopted including the forest management, manufacturing, use and end-of-life stages. CCFM allows the user to insert the cork type used as raw material and its respective quantity and the distances in-between the various stages. The user can choose among different end-of-life destination options for the used cork products. The option of inserting different inputs, allows the use of the present simulation model for different cork oak systems, in different countries and with different conditions. CCFM allows the identification of the stages and products with the greatest carbon footprint and thus, a better management of the sector from an environmental perspective. The Portuguese cork oak sector is used as an application example of the model. The results obtained showed that the agglomeration industry is the hotspot for the carbon footprint of the cork sector mainly due to the production of the resins that are mixed with the cork granules for the production of agglomerated cork products. The consideration of the biogenic carbon emissions and sequestration of carbon at the forest in the carbon footprint, resulted to a great decrease of the sectors carbon footprint. Future actions for improvement are suggested in order to decrease the carbon footprint of the entire cork sector. It was found that by decreasing by 10% the emission factor of the agglomeration and transformation industries, substituting the transport trucks by more recent ones and by decreasing by 10% the cork products reaching the landfilling end-of-life destinations (while increasing the quantities reaching incineration and recycling), a decrease of the total CF (excluding the biogenic emissions and sequestration) of the entire cork industry by 10% can be achieved.

Farmers’ reasoning behind the uptake of agroforestry practices: evidence from multiple case-studies across Europe

Potential benefits and costs of agroforestry practices have been analysed by experts, but few studies have captured farmers’ perspectives on why agroforestry might be adopted on a European scale. This study provides answers to this question, through an analysis of 183 farmer interviews in 14 case study systems in eight European countries. The study systems included high natural and cultural value agroforestry systems, silvoarable systems, high value tree systems, and silvopasture systems, as well as systems where no agroforestry practices were occurring. A mixed method approach combining quantitative and qualitative approaches was taken throughout the interviews. Narrative thematic data analysis was performed. Data collection proceeded until no new themes emerged. Within a given case study, i.e. the different systems in different European regions, this sampling was performed both for farmers who practice agroforestry and farmers who did not. Results point to a great diversity of agroforestry practices, although many of the farmers are not aware of the term or concept of agroforestry, despite implementing the practice in their own farms. While only a few farmers mentioned eligibility for direct payments in the CAP as the main reason to remove trees from their land, to avoid the reduction of the funded area, the tradition in the family or the region, learning from others, and increasing the diversification of products play the most important role in adopting or not agroforestry systems.

Integrating belowground carbon dynamics into Yield-SAFE, a parameter sparse agroforestry model

Agroforestry combines perennial woody elements (e.g. trees) with an agricultural understory (e.g. wheat, pasture) which can also potentially be used by a livestock component. In recent decades, modern agroforestry systems have been proposed at European level as land use alternatives for conventional agricultural systems. The potential range of benefits that modern agroforestry systems can provide includes farm product diversification (food and timber), soil and biodiversity conservation and carbon sequestration, both in woody biomass and the soil. Whilst typically these include benefits such as food and timber provision, potentially, there are benefits in the form of carbon sequestration, both in woody biomass and in the soil. Quantifying the effect of agroforestry systems on soil carbon is important because it is one means by which atmospheric carbon can be sequestered in order to reduce global warming. However, experimental systems that can combine the different alternative features of agroforestry systems are difficult to implement and long-term. For this reason, models are needed to explore these alternatives, in order to determine what benefits different combinations of trees and understory might provide in agroforestry systems. This paper describes the integration of the widely used soil carbon model RothC, a model simulating soil organic carbon turnover, into Yield-SAFE, a parameter sparse model to estimate aboveground biomass in agroforestry systems. The improvement of the Yield-SAFE model focused on the estimation of input plant material into soil (i.e. leaf fall and root mortality) while maintaining the original aspiration for a simple conceptualization of agroforestry modeling, but allowing to feed inputs to a soil carbon module based on RothC. Validation simulations show that the combined model gives predictions consistent with observed data for both SOC dynamics and tree leaf fall. Two case study systems are examined: a cork oak system in South Portugal and a poplar system in the UK, in current and future climate.

Does debarking intensity during the first cork extraction affect future cork thickness

Key messageThe use of increasing debarking during the first harvest of cork oak trees (Quercus suberL.) had no effect on the secondary cork calliper (thickness) in one of the trials and had a small negative effect in a second trial. Little evidence was found that debarking coefficient is a useful index for the management of cork oak stands.ContextThe Portuguese national legislation defines, without the support of scientific data or knowledge, maximum values of debarking coefficients (ratio of debarking height and perimeter at breast height measured over cork). For the first debarking, this value is limited to 2.0.AimsThe aim of this study was to determine the impact of increasing cork debarking coefficient on the calliper of the secondary cork extraction.MethodsTrees were located in two sites, in distinct regions characterized by low or high productivity classes. Three debarking coefficients were considered: 1.5, 2.0 and 2.5. The debarking coefficient for the first cork extraction was randomly selected for each tree. During the second debarking, a cork sample was taken from each tree. The samples were used for assessing secondary cork calliper. Differences in cork calliper were analysed using both correlation analysis and modelling approaches.ResultsDebarking intensity increase had a small negative effect on secondary cork thickness in the most inland site, while no effect was detected in the more coastal site.ConclusionIn our experiment, debarking intensity had a significant but small effect in one site and no effect in other sites. Debarking coefficients not only should be defined according to legal constraints but also instead should be adapted considering tree and site characteristics.

Evaluating the carbon footprint of the cork sector with a dynamic approach including biogenic carbon flows

PurposeThe aim of the present study is to assess the influence of two different attributional life cycle assessment (LCA) approaches, namely static LCA (sLCA) and dynamic LCA (dLCA), through their application to the calculation of the carbon footprint (CF) of the entire cork sector in Portugal. The effect of including biogenic carbon sequestration and emissions is considered as well.MethodssLCA is often described as a static tool since all the emissions are accounted for as if occurring at the same time which may not be the case in reality for greenhouse gases. In contrast, dLCA aims to evaluate the impact of life cycle greenhouse gas emissions on radiative forcing considering the specific moment when these emissions occur.Results and discussionThe results show that the total CF of the cork sector differs depending on the approach and time horizon chosen. However, the greater it is the time horizon chosen, the smaller the difference between the CF results of the two approaches. Additionally, the inclusion of biogenic carbon sequestration and emissions also influences significantly the CF result. The cork sector is considered a net carbon source when biogenic carbon is excluded from the calculations and a net carbon sink when biogenic carbon is included in the calculations since more carbon is sequestered than emitted along the sector.ConclusionsdLCA allows an overview of greenhouse gas emissions along the time. This is an advantage as it allows to identify and plan different management approaches for the cork sector. Even though dLCA is a more realistic approach, it is a more time-consuming and complex approach for long life cycles. The choice of time horizon was found to be another important aspect for CF assessment.