Life cycle assessment in the development of forest products: Contributions to improved methods and practices

<p>The prospect of reducing environmental impacts is a key driver for the research and development (R&D) of new forest products. Life cycle assessment (LCA) is often used for assessing the environmental impact of such products, e.g. for the purpose of guiding R&D. The aim of this thesis is to improve the methods and practices of LCA work carried out in the R&D of forest products. Six research questions were formulated from research needs identified in LCA work in five technical inter-organisational R&D projects. These projects also provided contexts for the case studies that were used to address the research questions. The main contributions of the research are as follows:</p> <p> Regarding the planning of LCA work in inter-organisational R&D projects, the research identified four characteristics that appear to be important to consider when selecting the roles of LCAs in such projects: (i) the project’s potential influence on environmental impacts, (ii) the degrees of freedom available for the technical direction of the project, (iii) the project’s potential to provide required input to the LCA, and (iv) access to relevant audiences for the LCA results.</p> <p>Regarding the modelling of future forest product systems, it was found that (i) it is important to capture uncertainties related to the technologies of end-of-life processes, the location of processes and the occurrence of land use change; and (ii) the choice of method for handling multi-functionality can strongly influence results in LCAs of forest products, particularly in consequential studies and in studies of relatively small co-product flows.</p> <p>Regarding the assessment of environmental impacts of particular relevance for forest products, it was found that using established climate impact assessment practices can cause LCA practitioners to miss environmental hot-spots and make erroneous conclusions about the performance of forest products vis-à-vis non-forest alternatives, particularly in studies aimed at short-term impact mitigation. Also, a new approach for inventorying water cycle alterations was developed, which made it possible to capture catchment-scale effects of forestry never captured before.</p> <p>To connect the LCA results to global challenges, a procedure was proposed for translating the planetary boundaries into absolute product-scale targets for impact reduction, e.g. to be used for evaluating interventions for product improvements or for managing trade-offs between impact categories.</p

Deep Perceptual Similarity is Adaptable to Ambiguous Contexts

The concept of image similarity is ambiguous, meaning that images that are considered similar in one context might not be in another. This ambiguity motivates the creation of metrics for specific contexts. This work explores the ability of the successful deep perceptual similarity (DPS) metrics to adapt to a given context. Recently, DPS metrics have emerged using the deep features of neural networks for comparing images. These metrics have been successful on datasets that leverage the average human perception in limited settings. But the question remains if they could be adapted to specific contexts of similarity. No single metric can suit all definitions of similarity and previous metrics have been rule-based which are labor intensive to rewrite for new contexts. DPS metrics, on the other hand, use neural networks which might be retrained for each context. However, retraining networks takes resources and might ruin performance on previous tasks. This work examines the adaptability of DPS metrics by training positive scalars for the deep features of pretrained CNNs to correctly measure similarity for different contexts. Evaluation is performed on contexts defined by randomly ordering six image distortions (e.g. rotation) by which should be considered more similar when applied to an image. This also gives insight into whether the features in the CNN is enough to discern different distortions without retraining. Finally, the trained metrics are evaluated on a perceptual similarity dataset to evaluate if adapting to an ordering affects their performance on established scenarios. The findings show that DPS metrics can be adapted with high performance. While the adapted metrics have difficulties with the same contexts as baselines, performance is improved in 99% of cases. Finally, it is shown that the adaption is not significantly detrimental to prior performance on perceptual similarity

Environmental assessment of Swedish clothing consumption - six garments, sustainable futures

The aim of this work was to map and understand the current environmental impact of Swedish clothing consumption. A life cycle assessment (LCA) was used to evaluate the environmental impact of six garments: a T-shirt, a pair of jeans, a dress, a jacket, a pair of socks, and a hospital uniform, using indicators of climate impact (also called “carbon footprint”), energy use, water scarcity, land use impact on soil quality, freshwater ecotoxicity, and human toxicity. The environmental impact of the six garments was then scaled up to represent Swedish national clothing consumption over one year.In addition to fulfilling this aim, the report is a unique and rich source of transparently documented inventory data on a large number of textile processes – hopefully this can be of use for other LCA practitioners. The report updates Roos et al. (2015), which was the first detailed LCA study of Swedish clothing consumption at the national level. Since the publication of the first edition, several LCA studies of textile production processes and global apparel consumption have been published, which have enabled us to refine the inventory model and benchmark the results.The work was done in Mistra Future Fashion, a cross-disciplinary research program in 2011-2019 which aimed to enable a systemic change in the Swedish fashion industry leading to sustainable development in industry and society

Towards a Quantified Design Process: bridging design and life cycle assessment

In this paper we describe how design researchers and environmental researchers are making a joint effort in overcoming the disciplinary barriers for collaboration. By comparing existing processes and identifying potential opportunities arising from inter-disciplinary collaboration the aim is to propose methods for building a bridge between disciplines. A model for “quantified design” is generated, and explored, relevant for designers, design researchers as well as LCA researchers

A Systematic Performance Analysis of Deep Perceptual Loss Networks: Breaking Transfer Learning Conventions

Deep perceptual loss is a type of loss function in computer vision that aims to mimic human perception by using the deep features extracted from neural networks. In recent years, the method has been applied to great effect on a host of interesting computer vision tasks, especially for tasks with image or image-like outputs, such as image synthesis, segmentation, depth prediction, and more. Many applications of the method use pretrained networks, often convolutional networks, for loss calculation. Despite the increased interest and broader use, more effort is needed toward exploring which networks to use for calculating deep perceptual loss and from which layers to extract the features. This work aims to rectify this by systematically evaluating a host of commonly used and readily available, pretrained networks for a number of different feature extraction points on four existing use cases of deep perceptual loss. The use cases of perceptual similarity, super-resolution, image segmentation, and dimensionality reduction, are evaluated through benchmarks. The benchmarks are implementations of previous works where the selected networks and extraction points are evaluated. The performance on the benchmarks, and attributes of the networks and extraction points are then used as a basis for an in-depth analysis. This analysis uncovers insight regarding which architectures provide superior performance for deep perceptual loss and how to choose an appropriate extraction point for a particular task and dataset. Furthermore, the work discusses the implications of the results for deep perceptual loss and the broader field of transfer learning. The results show that deep perceptual loss deviates from two commonly held conventions in transfer learning, which suggests that those conventions are in need of deeper analysis

LCA on fast and slow garment prototypes

This report summarises the environmental assessment work done in the Mistra Future\ua0Fashion program focussed on the potential to improve the environmental performance\ua0of garments and adapt them to a circular economy. The approaches examined in this\ua0report include reducing the environmental impacts from fast-fashion trends by making\ua0garments from paper-based materials, or by extending garment life cycles.This assessment considers two paper-based garments. One is made primarily from paper pulp but enhanced with a polylactic acid polymer. This garment is worn between\ua0two to five times before being recycled as newspaper. The other fast garment is\ua0made of paper pulp, polylactic acid and nanocellulose. It has a similar life cycle but\ua0is composted after use life. These garments are compared with a standard t-shirt. The report also considers a slow-paced scenario in which a polyester garment passes between several owners and is regularly changed to maintain its appeal. It is updated\ua0with a transfer sublimation overprint three times, making the garment darker each\ua0time. Later it is joined with an outer shell of new material using laser technology tomake a cropped, box-cut jacket.The assessment was performed using environmental life cycle assessment. More\ua0particularly, the assessment was based on attributional process analysis with cutoff allocation procedures and comparison with a traditional reference garment life cycle. Key environmental effect categories considered here include climate change (greenhouse gas emissions), freshwater eutrophication, freshwater ecotoxicity and human toxicity (cancer and non-cancer).The results indicate that the environmental outcomes of the paper-based garments can be competitive with the reference garment, particularly when the user is assumed to throw away a fully functional reference garment after five uses. This assumption may be true for some users, but the number of uses is considerably lower than the typical or the potential lifespan of the reference garment. The main factor assisting the paper-based garments is the reduction in the impacts per mass associated with material manufacturing (fibres, spinning, knitting), and also their lighter masses.\ua0Avoided impacts in the use phase play a secondary role on account of their location in\ua0Sweden with its low-carbon energy mix. The long-life garments are also competitivecompared with their reference garments. This is primarily a consequence of how extending garment life avoids the production of new garments. The environmental impacts associated with transfer sublimation dye reprinting and laser processing do\ua0not significantly impact the overall environmental performance of the extended longlife\ua0garments, though confidentiality of data prevents a full assessment of these.The garments in this report are pilot products and explorative scenarios rather\ua0than attempts to model existing business or behavioural patterns. The reader\ua0should therefore take care to keep the results in context when interpreting them.\ua0Nevertheless, the results suggest the value of pursuing the potential associated with these garment life cycles. We should also bear in mind that while the reference garments in this assessment are based on typical usage patterns, other more\ua0sustainable patterns are feasible

Improved environmental assessment in the development of wood-based products: Capturing impacts of forestry and uncertainties of future product systems

The prospect of reducing environmental impacts is a key driver for the development of new wood-based products. But as wood-based products are not necessarily environmentally superior to non-wood alternatives, there is a need to assess the environmental impact of the product and guide the development process. The aim of this research is to improve the methodology of such environmental assessments, to better capture the inherent uncertainties of future, still non-existent product systems and to improve the impact assessment of forestry.For capturing uncertainties, two approaches for scenario modelling were used in life cycle assessments (LCAs) of wood-based roof constructions and textile fibres. In the first approach, scenarios were set up to explore how different future technologies and methodological approaches (consequential and attributional) influence the assessment of life cycle processes occurring in a distant and uncertain future. In the second approach, scenarios with different geographical locations for the life cycle processes were generated by varying the future demand for textile fibres and the competition for forest land. Both approaches generated results which differed significantly between the scenarios; thus the approaches enabled a more comprehensive assessment than if only one scenario had been set up. The approaches can be recommended particularly for assessments of long-lived products and products with globally distributed supply chains.For improving the impact assessment of forestry, methods suggested in the literature were used and further developed in an LCA of wood-based textile fibres. The methods captured the land use impact on biodiversity and the water use impact on human health, ecosystem quality and resources. A new inventory approach was developed to better capture the system-scale effects that forestry can have on the hydrological cycle. Besides identifying opportunities for further methodological improvements, the methods generated meaningful results beyond what is offered by established methods for impact assessment. In particular, the consequential inventory approach made it possible to discern that land use can contribute positively to downstream water availability under certain conditions

Timber construction : knowledge gained, and knowledge needed

Byggandet står för en betydande resursanvändning och miljöbelastning. Att uppföra en större andel av byggnadsstommarna av trä har lyfts som ett möjligt sätt att bidra till ett mer hållbart byggande. Städer har engagerat sig i byggande med trä genom att anta särskilda träbyggnadsstrategier. För att fatta välinformerade beslut om val av byggnadsstommar behöver beslutsfattare vetenskapligt grundade kunskaper. Det saknas i litteraturen ett sammanställt vetenskapligt kunskapsunderlag vad gäller trästommars tekniska prestanda och hållbarhet. Den här rapportens syfte är att utgöra ett sådant underlag.More use of biobased materials has been proposed as important for reducing the high resource use and severe environmental impact of buildings. For increased and sound use of biobased building materials, decision makers need information on their technical and sustainability performance – but there is a lack of an updated synthesis of such information in the scientific literature. Therefore, this project has gathered scientific knowledge on the technical and sustainability viability of biobased building materials, with a focus on load-bearing structures. Specific objectives were to: a) Clarify technical challenges that bio-based building frames have been associated with, and how these have been handled. b) Clarify the sustainability impact of bio-based building frames, in a life-cycle perspective, compared to non-bio-based building frames. c) Explore the opportunities for bio-based building frames to be part of a circular economy, in terms of their reusability and recyclability

Timber construction : knowledge gained, and knowledge needed

Byggandet står för en betydande resursanvändning och miljöbelastning. Att uppföra en större andel av byggnadsstommarna av trä har lyfts som ett möjligt sätt att bidra till ett mer hållbart byggande. Städer har engagerat sig i byggande med trä genom att anta särskilda träbyggnadsstrategier. För att fatta välinformerade beslut om val av byggnadsstommar behöver beslutsfattare vetenskapligt grundade kunskaper. Det saknas i litteraturen ett sammanställt vetenskapligt kunskapsunderlag vad gäller trästommars tekniska prestanda och hållbarhet. Den här rapportens syfte är att utgöra ett sådant underlag.More use of biobased materials has been proposed as important for reducing the high resource use and severe environmental impact of buildings. For increased and sound use of biobased building materials, decision makers need information on their technical and sustainability performance – but there is a lack of an updated synthesis of such information in the scientific literature. Therefore, this project has gathered scientific knowledge on the technical and sustainability viability of biobased building materials, with a focus on load-bearing structures. Specific objectives were to: a) Clarify technical challenges that bio-based building frames have been associated with, and how these have been handled. b) Clarify the sustainability impact of bio-based building frames, in a life-cycle perspective, compared to non-bio-based building frames. c) Explore the opportunities for bio-based building frames to be part of a circular economy, in terms of their reusability and recyclability

Environmental impact of textile reuse and recycling – A review

This paper reviews studies of the environmental impact of textile reuse and recycling, to provide a summary of the current knowledge and point out areas for further research. Forty-one studies were reviewed, whereof 85% deal with recycling and 41% with reuse (27% cover both reuse and recycling). Fibre recycling is the most studied recycling type (57%), followed by polymer/oligomer recycling (37%), monomer recycling (29%), and fabric recycling (14%). Cotton (76%) and polyester (63%) are the most studied materials. The reviewed publications provide strong support for claims that textile reuse and recycling in general reduce environmental impact compared to incineration and landfilling, and that reuse is more beneficial than recycling. The studies do, however, expose scenarios under which reuse and recycling are not beneficial for certain environmental impacts. For example, as benefits mainly arise due to the avoided production of new products, benefits may not occur in cases with low replacement rates or if the avoided production processes are relatively clean. Also, for reuse, induced customer transport may cause environmental impact that exceeds the benefits of avoided production, unless the use phase is sufficiently extended. In terms of critical methodological assumptions, authors most often assume that textiles sent to recycling are wastes free of environmental burden, and that reused products and products made from recycled materials replace products made from virgin fibres. Examples of other content mapped in the review are: trends of publications over time, common aims and geographical scopes, commonly included and omitted impact categories, available sources of primary inventory data, knowledge gaps and future research needs. The latter include the need to study cascade systems, to explore the potential of combining various reuse and recycling routes