Productive project publishes again

The scientific article Sound Absorption of Tufted Carpets Produced from Coarse Wool of Mountain Sheep has been published in Journal of Natural Fibers. The article is co-authored by Jan Broda, Katarzyna Kobiela-Mendrek, Marcin Bączek, Monika Rom and Ingvild Espelien, and is an important contribution to the study of wool’s properties.

As part of the ongoing research in the WOOLUME project, looking at good utilization of coarse Polish mountain wool, is an important exploration. Tufting is a technique with cut and loop piles and to which degree this technique used on coarse wool can contribute to sound absorbing properties is interesting to study.

Some tufting history

Wool from Polish mountain sheep is coarse, highly differentiated both in thickness and length and contains a significant content of medullated fibers and kemp. Despite its poor characteristics, the wool can be used for the production of rag yarns fit for pile carpets with tufting technique. The carpets possess acceptable sound absorbing capacity comparable to other similar products obtained from other wool types, which is dependent on both pile types and their parameters.

The hand tufting technique was invented at the end of the nineteenth century in Dalton (Georgia, USA) where it was first applied for handicraft production of bedspreads, mats, and bathrobes. The technique involves stitching the yarn into the backing fabric to create a loop, cut, or mixed piles. Loop piles are formed when the yarn inserted is caught by loopers and pulled through the backing to a set length. Cut piles are formed by cutting the piles at their maximum length, with blades operating in tandem with the loopers. In the 1930s, a modified single-needle commercial sewing machine was adopted for tufting. The machine enabled tufting of thick yarn into muslin without tearing the fabric and was coupled with a knife to cut the loops.

Further development

In the next few years, tufting machines with four, then eight, twenty-four, or more needles enabling the formation of parallel rows were constructed. Machines were introduced to the industrial practice, which soon resulted in the rapid growth of the mechanized tufting industry. After the second world war, in the 1950s, tufting machines were getting more and more common and were equipped with several hundred needles to stitch hundreds of pile yarn rows. In the next years, tufting dominated carpet manufacturing. It is estimated that nowadays, tufting is a common technique widely used for the production of 90% of the carpets available in the market. The introduction of the tufting technique on a large scale coincided with the development of new synthetic fibers. Application of these fibers significantly accelerated the growth of carpet production. The new yarns, continuous filament nylon yarns in particular, provided good quality and high durability of carpets at a relatively low price, out-performing wool as the raw-material with a much cheaper price point.

Wool carpets used as floor coverings and interior decorations offer additional considerable advantages in terms of thermal insulation and heat balance in buildings. Moreover, such carpets are highly effective in controlling indoor noise and reducing the reverberation of sound. Carpets are some of the most versatile sound-absorbing materials which absorb both airwave sounds and reduce surface noise generation. Additionally, carpets reduce the impact of sound transmission between stories in multi-storied buildings.

Detailed characterization

In our previous studies, the acoustic performance of felt and fabrics manufactured from Polish mountain sheep wool was analyzed. The investigations showed that the wool of mountain sheep, which is often disregarded and treated as a waste product of sheep husbandry, is a valuable raw material that can be used to produce carpets and panels with good sound-absorbing properties. The paper presents the results of further studies on the utilization of coarse wool obtained from mountain sheep to produce rag yarns suitable for the production of pile carpets with the tufting technique. During this investigation, the raw wool and yarns were characterized in detail, and the possibility of using yarns in the tufting technique was explored. Then, the sound absorption capacity and transmission loss of the obtained materials in relation to the type of piles, pile height, and density were analyzed.

Conclusion: Apart from their decorative function, carpets produced from Polish mountain sheep wool with the tufting technique can serve as valuable sound absorbing material to lessen noise, reduce reverberation, and improve the acoustic comfort of the room.

Access to the full article is provided in this link.

This research was funded by the Norway Grant titled “Polish sheep wool for improved resource utilisation and value creation.” NOR/POLNOR/WOOLUME/0007/2019

Garbage talk: Easily outdated, but difficult to date

Text by Tone Skårdal Tobiasson

The results from the Wasted Textiles pilot study, executed by four Master-students Camilla Sunde (UiO), Eva Hovda (NTNU), Siri Vestengen (NTNU) and Saeid Sheikhi (Høyskolen Kristiania) has now been published. Avfall Norge and their summer program REdu, were able to get the pilot financed by The Norwegian Retail Environmental Fund, and the results from the pilot where the four students tested out a system for picking analysis that captures vital information on the textiles that mainly had status as garbage is presented in the report.

The analysis conducted in Slemmestad Mepex-center offers valuable insights into the current status of discarded textiles in Norway. The “TPR” (named for the Targeted Producer Responsibility idea) picking analysis results provide us with information regarding the composition of fibres, garment age, country of production, and brand details of the discarded textiles. This data was taken from the care labels on the products. Over a period of 13 days, the team successfully managed to analyze a total of 3024 items using the TPR picking analysis method that they fine-tuned based on a combination of wardrobe studies and classic waste picking analysis.

Picking analyzes are used for other product groups to say something about use. In food, this form of analysis is used to monitor how much edible food is thrown away from private households (see e.g., this study (miljodirektoratet.no)) and to monitor and reduce food waste from institutions. The textiles analysed in the report originated from various waste streams: Mepex’s “Klesbyttedag” (clothing swap day), TRV (Trondheim city pilot project on collecting textiles) and residual waste. Residual waste is the hardest to work with because of smell and humidity making it difficult to weigh the items. In the report, the TRV waste is the largest and most important, representing 91.4 % of the material. Textiles from TRV-pilot are supposed to be damaged textiles. Residents of the pilot area in Trondheim were given instructions and special bags for damaged textiles, clothing and shoes. Residents are encouraged to deliver usable textiles to collection boxes already located in the area and to put the bag with destroyed textiles outside for collection on a fixed day, every four weeks. The interns photographed all the items, gave each textile item a number, and registered information on if the brand could be identified if the care label was intact if there was a year of production or when the product entered the market anywhere on the textile, country of origin, fibre-composition, what state of ‘used up-ness’ the items were in, the weight, etc.

The findings in the REdu project, are based on a small sample, 3024 items all in all. 2564 of 3024 items (the total registered) had the brand present either on the label or a logo visible. 708 distinct brands were identified, but a few dominated, H&M being in the lead, followed by Cubus, Lindex and KappAhl. Out of the 3025 analysed textiles only 95 items had the year of production on their care labels, 2905 did not include this information. Of these clothing pieces 14 of them were from NameIt (a Danish children’s brand), 7 from Vero Moda, 7 from Selected – all three Bestseller brands, and 6 of them were from Bik Bok. For the remaining individual brands, 61 items were with a production year. Some brands have labels with codes that may or may not contain this information, that they would need to explain. Some brands said they are willing to help with this information.

The progress in the TPR picking analysis time efficiency showcases the potential for applying picking analysis and the time it might require. In the TPR approach, they utilised several input parameters and managed to analyse an average of 234 items per day, equivalent to around 79 kg. On the other hand, the “fast TPR method” employed fewer input parameters while still capturing details for each item. With this approach, the average number of items examined within a 30-minute span is 29, equal to 7.6 kg per person. The time used to analyze was affected by the different textiles analysed, whereas multilayer and complicated multi-fibre items were more time-consuming.

In assessing the potential of machine learning in textile waste management, the results are promising, but not without challenges. The initial model focusing on textile type classification achieved significant accuracy, with an accuracy of 82.25 %, emphasizing the practicality of using automation for sorting textiles. However, the usability classification model highlighted the need for comprehensive and quality data inputs to predict an item’s reuse potential. While machine learning presents great promise in enhancing sorting efficiency, determining reusability, and promoting fibre-to-fibre recycling, its successful deployment hinges on several factors. These include the expansion and quality improvement of datasets, the integration of advanced sensing technologies, and a broader assessment of environmental, economic, and social impacts.  Ethical considerations are paramount, especially in ensuring that machine learning models operate effectively and ethically. By partnering with Extended Producer Responsibility (EPR) schemes, feedback loops between producers and waste management can be optimized.

The data gathered from the examined items highlights the possibility of reusing materials in the textile sector that the consumers themselves deem as garbage.  Assessing the level of wear and tear in clothing was relatively easy, factors like pilling, stains, discolouration, damaged zippers, missing buttons, holes, and general signs of use are easy to spot and register. A majority of the items were in a good usability state, where 42% of the textiles scored a condition of 4 (5 being the highest score indicating mint condition, while 1 is not at all reusable), suggesting that the discarded textiles were not “used up”. Also, 21 items were found with their price tags still attached. While some items displayed minor damages, many of these can be fixed effortlessly at home, pointing towards the value of imparting basic repair skills to consumers.  Notably, 17.66% of items had a maximum usability score of 5, indicating a considerable number of nearly new items being discarded. We will remind the reader there that these were supposed to be worn out or «broken» items, as fully usable textiles were supposed to be donated in the donation boxes.  

The data obtained from this analysis holds significant importance in comprehending the possibilities of automated sorting, material reuse, and recycling. It provides a foundation for introducing strategic methods like extended producer responsibility (EPR) and policies focused on waste prevention. Hopefully, the TPR picking analysis can be used to assess eco-modulated environmental fees in an EPR scheme, aiming to ultimately decrease excessive textile production in the fast fashion sector. In 2022, 105 913 tonnes of new textiles which are equivalent to 19.3 kg per capita, were put on the Norwegian market, so future data collection is not in danger of not having materials to study, once textile waste will be collected separately from 2025.

Click here to read the full report (avfallnorge.no).

REdu result seminar

Webinar, Friday 11th of August 2023, 09:00-10:00, Oslo/Zoom.

Four intern students in the Avfall Norge REdu project have worked on the SIFO proposal for TPR (read more about this here), and will present the results from this work at 9 am CET on the 11th August via Zoom. We are eagerly awaiting these results, as this is the first time we will get answers to whether the textiles that end up in various waste streams can be identified by brand, if we can estimate how long their duration of service has been and in what state they are for reuse or recycling.

The seminar is free and open to all and can be accessed via this zoom-link. The meeting ID is 828 0060 9300.

Welcome!

Both Wasted Textiles and the REdu picking analysis project are financed by the Norwegian Retail Environmental Fund.

THE PLASTIC ELEPHANT: Overproduction and synthetic fibres in sustainable textile strategies

Authors: Ingun Grimstad Klepp, Lisbeth Løvbak Berg, Anna Schytte Sigaard, Tone Skårdal Tobiasson and
Lea Gleisberg

Summary

In this report, we examine national, international and corporate strategies for sustainable textiles to understand if and how they embrace the increased production volumes based on synthetic materials, which can be referred to as the ‘plastic elephant in the room’. This is done through a lens of four questions. First, we look at whether the strategies discuss growth in production volumes and possible measures to stop this growth. Second, we examine whether they address the plastification of textiles. By plastification, we mean the increasing share of plastic fibres used for textile production. Third, whether they discuss the raw material for plastics, and fourth, plastic waste. The results show that none of these questions that can reduce the environmental impacts of clothing production are given a central role in the strategies.

Click here to read the full report.

PhD Masterclass on Wardrobe Research

13th of April this year an online PhD masterclass was conducted within the scope of the CHANGE work package 5. The masterclass was online and involved the currently eight PhD students working with the wardrobe method or closely related methods and had the purpose of facilitating exchange of shared methodological implications, involved issues of interest, and the build-up of research network for young talents.

The 2-hour masterclass was informed by rapid pecha kucha type presentations of ongoing work and pre-formulated questions to facilitators and peers, and the workshop was hosted by Else Skjold who is PI of work package 5 of the CHANGE project. This work package involves, among other things, consolidation of existing wardrobe research and talent recruiting for new young research talent. Below is elaborated how the three themes cross-fertilized and interesting discussion that will hopefully just be the beginning of future work across the CHANGE partners to come. The presentations and discussions involved three selected topics emerging out of the ongoing PhD studies which were:

  • Wardrobe Practices
  • Secondary Use
  • Textile Techniques and Use

Wardrobe Practices

How can we understand the interactions between wearers and garments within the specific site of the wardrobe both at micro- and macro-level? This has always been the core pillar of wardrobe research since it was established in the mid 2000’s, and it was very interesting to see how young scholars pick up on this and formulate new ideas within the scope of their thesis work. A particular strong focus on local dress cultures and its effect on individual wearers were highlighted in this session, that brought about fruitful discussions on situated and contextual dress practices and how they are affected by climatic, cultural, economic and functional parameters.

Secondary Use

How can wardrobe research methods cast a light on the types of mechanisms and value creation that takes place between wearers and their vintage- and secondhand garments? This line of research is an interesting extension of ‘first generation’ wardrobe researchers’ work, in that it investigates what actually happens with garments beyond first use. This way it speaks back to concepts such as design for longevity/circularity and what they entail in the lifespan of garments between generations, body types, dress cultures and shifting ideas of fashion over time. And furthermore, how that informs practices of acquiring and discarding – an issue that has also been central within wardrobe research right from early pioneer studies in the early 1990’s.

Textile Techniques and Use

What types of competences used to be involved in maintaining personal wardrobes historically and how can we learn from this in an era with overproduction and overconsumption? Mending, repair and repurposing are all practices that have been deeply integrated in historical practices of use, as resources were typically scarce and costly – as opposed to now where much knowledge has been lost due to cheap, replaceable products and short use phases. This session looked into wardrobe maintenance practices of embellishment, print or other textile techniques for prolonging the lifespan of clothing, for projecting activist ideas, and generally for informing future practices and aesthetics of scarcity.

The masterclass will be repeated during the fall of 2023.

Ecodesign position paper: Textiles and footwear

In a position paper from the Change and Wasted Textiles projects, authors Kate Fletcher, Irene Maldini, Ingun Grimstad Klepp, Kirsi Laitala, Jens Måge and Tone Skårdal Tobiasson have addressed the background document from EU’s Joint Research Centre on Ecodesign for Sustainable Products Regulation (ESPR).

The main theme in the position paper, is that the JRC document Preliminary study on new product priorities lays the basis to increase environmental burdens rather than reduce these. Therefore, in the paper, the authors ask that the work with the ESPR incorporates more empirical understanding about ecodesign, clothing consumption, and textile and fashion design. This in order that the directive will have the effect of reduced environmental burdens (including on climate) and will minimize inappropriate or unintended side effects.

The aim in writing the paper is to support the ESPR process for textiles and footwear in fostering deep and lasting environmental change.

The authors applaud the efforts of the EU in regulating the textile and footwear sector and agree in the priority that has been assigned to clothing and footwear on the bases of high consumption volumes in the EU, potential environmental improvements, and lack of previous regulation. However, it is the view of the authors that the current work with the Ecodesign Directive is based on some assumptions that are not in line with the knowledge that is there, nor is it targeted towards the main and interconnected challenges in clothing and textiles: overproduction and the increasing plasticization of the material content of products.

These two factors are interconnected due to the fact that an increase in production is not possible without the cheap, easily available fossil fuel-based raw material for fibres, materials, dyes and other processing chemicals.

It is therefore questionable whether textiles and footwear should actually be the initial priority for ESPR. Perhaps starting with cement would be better.

Sufficiency on the agenda

Sufficiency advocates from different sectors came together on May 4th at the Sufficiency Summit.

Co-organised by Sciences Po (France) and University of South Australia, and chaired by Dr. Yamina Saheb and Professor David Ness, the Summit brought together governments, NGOs, and academics advocating for sufficiency in transport, the built environment, food, and clothing from different locations globally. 

Irene Maldini, a researcher in the Change project at Consumption Research Norway (SIFO) at OsloMet participated in the panel about sufficiency and clothing, chaired by Katia Vladimirova from the University of Geneva. Samira Iran (Berlin Technical University) and Yayra Agbofah (Ghana-based NGO The Revival) also contributed. The key note for this part of the summit, was delivered by Lindita Xhaferi Salihu.

Irene Maldini (left) and Katia Vladimirova.

The session exposed attendees active in other sectors to research on individual initiatives to reduce textile and clothing consumption in the Global North, the problematic impact of growing volumes of imported second hand textiles in Ghana, and progress and resistance to include production volumes reductions measures in contemporary environmental policy for clothing and textiles. Maldini pointed specifically to the lack of attention to volumes in the policy measures.

Overall, the event placed great emphasis on inequality of resource consumption across the globe and the inefficiency of the market as a system to cover people’s needs. There was an overall consensus that stronger policy interventions are needed to enable reasonable levels of consumption across the globe, and that individual actions will follow.

Read more about the event here.

A full PLATE with a 7-course SIFO menu

Photo Tuomas Uusheimo

Holding on or letting go? Why don’t consumers complain more? Why do we hang on to stuff that is flawed? How to make fast fashion out of fashion and actually degrow the textile sector? All these questions will be answered at the PLATE conference at Aalto University, in Espoo, Finland.

At the end of May and beginning of June, Consumption Research Norway SIFO at Oslo Metropolitan University will partake in the biannual PLATE (Product Lifetimes and The Environment) conference with a full menu of all in all six papers, and all in all four presenting findings from LASTING, where one is by authors from the Norwegian University of Science and Technology.

The project Change will also be presented with volumes of consumption as the appetizer. Studying clothing consumption volumes through wardrobe studies: a methodological reflection is written by Irene Maldini, Vilde Haugrønning and Lucrecia de León. As not all wardrobe methods take advantage of their volume-centric possibilities, the paper explores lessons from a wardrobe pilot study conducted in Uruguay, Portugal and Norway in 2022 with both male and female respondents. Preliminary findings show that a volume perspective on wardrobe research can give valuable insights on the particularities of clothing use in relation to quantities.  

Putting on a different set of glasses

In another paper, which is a result of the Wasted Textiles project, this is also explored related only to textiles and clothing: Regulating Fast Fashion out of Fashion, authored by Kerli Kant-Hvass and Ingun Grimstad Klepp. The analysis underpinning the paper is based on a review of 10 textile strategy documents from public, private and non-profit organizations, on whether and how growth and overproduction in the textile industry is being addressed. Merging this with research and findings from the opposite end of the value-chain than these textile strategy documents do (which use design and a focus on “preferred fiber” choices to potentially optimize lifetime), the paper puts forward Targeted Producer responsibility (TPR) as a means to curb volumes effectively and thus reduce environmental impacts.

Another paper, written by Kirsi Laitala, Lisbeth Løvbak Berg and Pål Strandbakken, addresses consumers’ use and knowledge of the Consumer Purchases Act by asking: Why won’t you complain? Consumer rights and the unmet product lifespan requirements. The paper discusses the reasons for not complaining, based on six consumer focus groups, where in total 36 consumers described furniture, electronics, and textile products that they were dissatisfied with and hadn’t necessarily taken the trouble to claim their consumer rights.

Clearer guidelines in order

There is a need for clear guidelines on what the consumer rights are for the specific products, the authors write, to make it clear what is considered unacceptable abrasion and normal use, but also to differentiate between commercial warranties and legal rights. Complaints are, after all, an important avenue for businesses to gain information about the performance of their products, and thereby improve them.

In Norway, the right to complain is extended to 5 years for some durable goods, which exceeds the EU requirements of 2 years. This creates confusion about which products and which duration is valid, where consumers often link this to price, rather than the type of product. In addition to clearer guidelines, there are possibilities for new technical solutions to facilitate the storage of receipts and purchase information related to each product, which was especially problematic for low-priced items. Digital product passes, which is on EU’s menu of policy instruments, may be developed with this in mind, and could also include information about consumer rights.

Focus groups offer insights

Two other Lasting papers, are both about what we keep or discard and why, and are based on focus groups, but also some interviews with business representatives. The overarching theme was product longevity of three product groups: electronics, textiles, and furniture. In Flawed or redundant: products with long lifespans against the odds, co-authored by Harald Throne-Holst and Kirsi Laitala, the theme is explored related to reasonings behind keeping things – by only storing them and not using them – or trying to use them even though they are broken or flawed. Five groups of reasoning were presented: Economical, Ethical, Social, Emotional, and Intentions.

In Holding on or letting go? Conflicting narratives of product longevity: a business vs. consumer perspective, authors Lisbeth Løvbak Berg and Marie Hebrok have found that technical and emotional durability are the two dominant ways of understanding product longevity by business representatives, and as such what they aim to embed in their products. Consumers, however, tell a different story, of living with their things, of use, of time passing, and life events triggering change – factors that are external to the product itself. The authors argue that corporate narratives of product longevity divert our attention away from production toward consumption, keeping questions of volume and growth at arm’s length.

Stockings as stress

In relation to durability, the Reduce project will present The devaluation of stockings. Tone Rasch, Ingrid Haugsrud, Kirsi Laitala and Atle Wehn Hegnes (Tone is associated with the Norwegian Museum of Science and Technology) explore nylon stockings for women as an example of a product that first was recognized as high fashion, but later has been devalued and is now seen almost as a single-use product. Thin stockings represent a good example of how we value and take care of delicate items has a significant contribution to their lifetimes. Looking into the historical context is beneficial for learning about the points in time when changes occurred and how they contribute to consumer practices.

The weakest link: How technical lifespan extension can be counter-effective for climate goals looks at scenarios for kitchen durables (fridge, dishwasher, stove, and kitchen cupboards) to explore lifetime extension, and investigate the extent to which these interventions could in fact be counter-effective for climate goals set for 2050. The authors, Kamila Krych and Johan B. Pettersen, found that the extra resources invested to ensure more durable products that anyways can land in waste bins prematurely, can be counter-effective in reaching the climate goals set for 2050.

Tasty alternatives

Faster environmental benefits, the authors write, could be achieved by increasing the repair rates by extending product warranties, subsidizing repair services, supporting the development of innovative repair businesses, demanding the availability of spare parts at affordable prices, and increasing the convenience of repair. The paper also points to policy addressing “problematic” products as more effective, such as dish-washers that fail more frequently. A belief in design-focused interventions, is clearly questioned, as the authors see this as taking longer to bring effect.

So, all in all, attendees should be well-satisfied and full of new knowledge, considering this rich menu, which is of course only a small part of the three-day proceedings in Finland. The research papers will be published after the conference.

Microplastics or microfibers: Does anyone really get what this is about?

OPINION: What we do know, is that all synthetic clothing and materials, sooner or later, will become microplastics, a «time-delayed» pollution bomb. And thus, they will ultimately become a problem for seabirds, and us.

A new report on microfibers in waterways is gaining attention, as it claims the results show more natural fibers than synthetic ones, and therefore demonizing microplastics is wrong. However, a very recent study on the intestines of seabirds gives a different conclusion: Fossil-based particles do cause harm.

The recent report from The Microfibre Consortium (TMC), together with the Norwegian Research Center/NORCE has analyzed samples taken along the coast of Kenya and Tanzania, and found that of 2403 textile fibers in the water, 55 per cent were of natural origin, 37 per cent were synthetic and 8 per cent viscose/rayon-based.

To read this op ed, written by Professor Ingun Grimstad Klepp, Founder of Fibershed, Rebecca Burgess and journalist and writer Tone Skårdal Tobiasson, follow this link.

Winter wheat + wool pellets work well

It turns out that Polish mountain sheep wool can be successfully used as a nitrogen-rich, organic fertilizer in organic farming. This enables utilization of coarse wool, which is not suitable for textile processing, to be used and lead to zero-waste from wool shearing.

“Utilisation of waste wool from mountain sheep as fertiliser in winter wheat cultivation” is the title of an study from the University of Bielsko-Biala published in the Journal of Natural Fibers, Volume 20 Issue 2. Authors are all part of the WOOLUME project, Jan Broda, Monika Rom, Andrzej Gawlowski and Katarzyna Kobiela-Mendrek.

Coarse wool obtained from mountain sheep has low economic value and is treated as a troublesome by-product of sheep farming. To find ways to utilize it, wool deemed as waste was separated from the better-quality wool during sheep shearing, and used in experiments as a fertilizer in winter wheat cultivation.

During the preliminary tests, it was found that un-scoured wool did not contain excessive amounts of heavy metals or environmentally problematic contaminations, and could therefor safely be used as fertilizer. After this was established, the raw wool was cut into shorter segments and mixed with the soil, and how this influenced winter wheat growth was examined during two seasons.

Simultaneously, the progress of wool biodegradation and the nitrogen content in the soil were analyzed. It was found that, during the growth period, nitrogen compounds are slowly released into the ground, and the content of nitrogen in the soil was closely correlated with the progress of wool biodegradation.

Stems of the winter wheat Kilimandzaro variety grown in plots with different wool content at the end of growing season. With increased wool content, the stems are visibly longer.

Released nitrogen thus positively impacts wheat growth in various stages, which is manifested by higher tillering degree, more intense leaf color, higher stems and finally, greater yield. Wool added into the soil reveals its positive influence on wheat development up to two harvests. Mountain sheep wool can be successfully used as a nitrogen-rich, organic fertilizer in organic farming. This enables utilization of coarse wool, which is not suitable for textile processing, according to the zero-waste strategy.

Field of winter wheat Sacramento variety at the stage of stem elongation with marked plots established in: 1/first year; 2/second year.

Read the full article in Journal of Natural Fibers here (tandfonline.com).