What’s happening to my tea?

RESEARCH DISSEMINATION: AMERICAN GEOPHYSICAL UNION (AGU) CONFERENCE

By Ellie Biggs
University of Southampton

In December 2015 John, Niladri and I attended the AGU annual fall meeting to present the preliminary findings of our research. We presented two posters; one focussed on the value of the tea landscape and the other on managing water resources for a climate-smart approach.

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Niladri, Ellie and John at the climate-smart analysis poster

Our sessions were very engaging with a range of questions from those interested in the climate-yield analysis methods, to impacts on the livelihoods of tea stakeholders, to concern regarding a reduction in personal tea supplies.

We are now working on the last stages of data collection and finalising all our analyses, writing up our findings for publication in journals. We are also starting to develop a basic web-based decision support tool for the Tea Research Association to use in-line with their advisory services for member gardens. Training will be undertaken at TRA in February and wider dissemination of research will also occur through a final workshop and community fair with dates to be confirmed.

How is climate affecting tea quality in China?

GUEST BLOG: Q&A with an ethno-botanist on the SOCIO-ECOLOGICAL ASPECTS OF TEA QUALITY

Answering the questions: Dr Selena Ahmed
Assistant Professor of Sustainable Food Systems
Food and Health Lab, Montana State University

Is climate change changing the taste of tea? Can producers and consumers perceive such changes? What are implications for farmer livelihoods and benefits we derive from tea as consumers? In this blog we find out more from a team of researchers working in China.

What’s so special about tea in China?
Tea is cultivated, processed and prepared in diverse ways in China. This diversity makes tea in China very special to me. China is regarded the motherland and centre of genetic diversity of tea with over 1,500 cultivars of the tea plant. It also grows in gorgeous systems from forests to shade-grown gardens to mixed plot fields.  I recently returned from a great field season in Yunnan Province of SW China where I sampled tea and interviewed farmers on climate effects on tea quality. As part of this fieldwork, I had the opportunity to eat fresh tea leaves harvested right off the plant – this is one of my favourite edibles. I also drank what seemed like infinite cups of spring tea that the tea farmers I was staying with harvested the same very week. This tea is characterised as full-bodied, complex, and bitter-sweet. What makes tea from these gardens in Yunnan discernible is the lingering sweet after taste that sticks like honey to the back of the throat in a sensation known in Chinese as gaan.

When is the best time to taste tea?
Anytime! With that said, spring tea harvest has come to be my favourite harvest. The spring harvest is also the most desirable harvest for tea entrepreneurs who make the trek out to the tea mountains from major cities of China in search of the young spring buds. The spring is when the buds and leaves are awakening from winter dormancy and also when the plants grow in relatively dry conditions that are suitable for tea quality. This spring, tea farmers in Yunnan Province shared that the tea harvest started a little earlier than in the past, while being a little later than in previous years. Tea farmers attribute this to changing climate factors as well as to land use change that impacts the local micro-climate.

What attributes determine the quality of tea?
Tea quality is determined by sensory characteristics and secondary metabolites that impart health benefits for human consumers. Secondary metabolites are compounds that are produced by plants for defense. Unlike animals that can move away from predators or uncomfortable environmental stress, plants are rooted and have evolved defense compounds to protect themselves from a range of environmental stress. Thus, tea quality is intricately linked to environmental, agrarian, and cultural factors. For example, the quality of tea harvested from an organic system is different than that harvested from a conventional system. Or that harvested from high altitudes varies from that at lower altitudes on the same mountain. I have been working in the motherland of the tea plant, SW China, since 2006 to examine how changing environmental and cultural factors impact tea quality. Here, indigenous communities cultivate tea in diverse systems including shade-grown agro-forests and mixed cropping. Leaves harvested from these systems differ in their quality.

So why is your research important?
Our research on climate effects on tea quality is important for several reasons. First, tea is the most consumed beverage in the world after water and thus any changes in tea quality from climate change would have consequences for a notable percentage of the world’s population. 
Second, in many instances, tea is produced by smallholder farmers as a primary source of income. Changes in income derived from tea that are driven by climatic shifts would thus impact these smallholder farmers. Farmers have continuously shared their perspectives regarding how climate factors and seasonality are major drivers of tea quality. Third, our project fills an important research need by focusing on climate effects on  crop quality. While it is well understood that more frequent and intense climate events in many areas are impacting crop yields, the impact on crop quality is less acknowledged. Knowledge on tea quality is critical for food systems that benefit both farmers and consumers through high-quality products. The framework developed and tested by our research may be applied to other speciality crops such as fruits, vegetables, wine, coffee, tea, maple syrup, and chocolate – all these products have unique secondary metabolite profiles that are notably impacted by the environment and management practices.

How do you measure the effect of climate on tea quality?
We are examining climate effects on tea quality through a multi-pronged approach involving field sampling of tea, controlled field and greenhouse experiments, laboratory analyses of biochemicals, sensory evaluation, consumer taste experiments, farmer surveys, and climate modelling. While data exists to create simulations on how tea yields in China may vary with forecasted climate models, there is a lack of information on how tea quality will vary. Consequently, we are collecting tea quality data through sampling of tea during different seasons that have distinct temperature and precipitation characteristics including the spring, summer and autumn season. We started this sampling in 2012 and plan to continue until 2016. In addition to our field site in Yunnan, we are also sampling in Zhejian and Fujian Provinces. At each location, we have a high elevation and a low elevation site. After the samples are harvested, they are used for various sensory experiments with tea farmers and connoisseurs, tea panels, and general western consumers. A portion of the samples are also sent to the lab where they are analysed for key aroma compounds that determine tea quality.

What have your results found so far?
Preliminary findings from our work have found that tea functional quality significantly varies with extreme weather events, which are becoming more frequent with climate change. Specifically, compared to an extreme spring drought, tea leaves grown during the monsoon at our study site in SW China were up to 50% higher in terms of growth parameters while concentrations of major compounds that determine tea functional quality were up to 50% lower. This suggests that changes in precipitation may have a dilution effect on tea quality or cause drought or water stress.

What does this mean for farmers?
A decrease in tea quality is associated with a decrease in tea prices and income derived from tea sales; which substantially impacts upon farmers’ livelihoods. Our findings validate farmer perceptions that precipitation impacts tea quality. Extrapolating findings from this study to long-term climate change suggests variability for farmers and the need to tap into farmers’ knowledge of management practices to mitigate climate risks in their agro-ecosystems for the sustainability of tea production.

What’s next?
We will continue sampling extreme seasonality variability for the next two years and we will carry out controlled experiments with tea plants in conditions that manipulative climate scenarios in tea-producing areas. This work will be coupled with interviews with farmers and consumers. Our studies with farmers involve determining behavioural responses of consumers to climate-induced changes in tea quality and yields and their implications on tea markets regionally and globally. At the farm-level, we are documenting how livelihood changes and tea farmer knowledge of climate effects on crop quality and yields feedback into the way farmers adapt their management and tea processing to adapt to climate conditions.

Can you predict whether the Chinese tea will taste different in the future?
Ultimately, we will input tea quality into a climate model to simulate future tea quality in different geographic areas on the basis of climate projections. We will also integrate findings from our lab analyses and interviews to use this evidence to develop management plans and policy suggestions for tea agro-ecosystems and processing, and ultimately facilitate societal action towards enhanced sustainability of food systems.

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In addition to tea, Selena has begun to explore how climate is impacting other speciality crops. She recently received funding with another interdisciplinary team to explore climate effects on maple syrup quality and socio-ecological responses.

Selena’s research is funded by the USA National Science Foundation’s Dynamics of Coupled Natural and Human Systems (CNH) Program. The interdisciplinary team of scientists examining how climate effects tea quality includes Colin Orians (chemical ecologist), Albert Robbat (chemist), Tim Griffin (soil scientist), Rick Stepp (cultural anthropologist), Sean Cash (agricultural economist), Corene Matyas (climate scientist), Wenyan Han (tea and soil scientist), and Selena Ahmed (food systems scientist). Each of the team contributes different perspectives and methodologies from their fields to address this interdisciplinary issue. If you have any questions on their research please direct them to selena.ahmed@montana.edu.

For more info on their research see www.teaclimate.org

Sustainable Landscapes and the Tea Value Chain

INTEREST PIECE: TEA2030

by Ellie Biggs
University of Southampton

“Tea2030… [identifies] a real opportunity for tea to become a ‘hero’ crop. A hero crop delivers more than just a commodity. It also delivers major benefits to the millions of people involved in the tea sector, the planet and the wider economy.”

Having stumbled across Tea2030 whilst doing background reading for our project, I decided to dig a little further to find out more. Initiated by Forum for the Future Tea2030 is a global collaboration bringing multiple stakeholders together to explore the future challenges facing the tea sector. Tea2030 have highlighted 29 big challenges relating to future sustainability of tea landscapes, including factors such as demand for labour, water scarcity, productivity gains, availability of inputs and climate change impacts. These challenges require a multi-institutional response in order to address the entire tea value chain and promote future tea sector sustainability. Tea2030 has facilitated this consortium though bringing together tea producers, brands, certifiers, retailers, government, NGOs and researchers.

A Sustainable Tea Landscape

Given the synergies between some of the identified challenges of Tea2030 and our UKIERI project objectives, I took their website invite offer up to contact the team regarding the possibility of working with them. I received an enthusiastic response inviting me to attend a workshop the team were hosting in London. This half-day event (held in November 2014) provided an excellent opportunity to engage with many tea industry experts and a chance for me to discuss our research with a captive industry-focussed audience; in fact, out of the 30 attendees only two were from academic institutions.

The workshop topic focussed on making sense of sustainable landscapes for the tea sector. A highly interactive atmosphere provided an ideal set-up to push forward key conceptual thinking on defining sustainable landscapes for the tea industry, select a series of case study regions to pursue at the landscape-level, and explore tools which are pushing forward multi-scale sustainable solutions throughout the tea value chain. Following break-out sessions, group consensus refined three internationally important tea regions as case studies: (i) Assam, Northeast India (ii) Southern Malawi, and (iii) Mau, Kenya. These landscapes are of varying scales with high economic value, a diversity of environmental attributes and have both common and distinct sustainability challenges. Various ideas arose regarding a clearer definition of sustainable landscapes, including the need to explicitly integrate sustainable livelihoods. Tools for sustainable landscape management within the three regions were discussed but it was evident that case studies needed further development to fully evaluate the success and potential of landscape approaches.

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What’s next for Tea2030?

The final outcome of the workshop identified key roles for members of the Tea2030 consortium to pursue in making the value chain more sustainable at a landscape scale. These roles relate to ideas which have potential to build upon ongoing solutions and address opportunities in the case study regions. For example, an idea to better promote the consumer-producer relationship for retailing tea, similar to the success achieved within the coffee industry in recent years whereby consumers are engaged with the production status of the coffee they are purchasing (e.g. labelling of fairtrade certification; organic; tea estate responsible for production etc.), was suggested as an opportunity for multiple Tea2030 actors to play a role in promoting sustainable practices to enhance the value chain for case study areas. The next stage is for members to take their key roles and translate these into a case for action to ensure that tea landscapes have future sustainability and tea can be championed as a hero crop through a sustainable value chain. Further workshops will be planned to discuss collaborator engagement and progress.

A future for UK tea?

INTEREST PIECE: ENGLISH TEA V ASSAM TEA

by Ellie Biggs
University of Southampton

“There is no trouble so great or grave that cannot be much diminished by a nice cup of tea.”

The initial stages of our collaborative research venture have sparked great interest for me in tea to a level purely beyond that of drinking it! Our new research project is investigating climate impacts on tea production in Assam, India. From this I’ve developed a side interest in the UK tea industry; an interest I regard as suitably justified given that we consume so much of the stuff. In fact, I have learned since commencing the project that tea is actually grown in the UK, which is a highly exciting prospect. Currently only one tea estate produces tea in England and that is the Tregothnan plantation in Cornwall. According to their website, “Tregothnan is one of the very best tea regions in the world. Its cool climate and inimitable uniqueness is essential for the best of teas.” So how does English grown tea differ to that grown in Assam?

Growing differences: Cornwall V Assam
Acidic soils and a damp environment provide ideal tea-growing conditions at Tregothnan. The Camellia sinensis tea bush grows especially well in the damp and temperate Cornish valleys. In comparison, Assam is also especially damp given the monsoon rains rejuvenates the landscape every summer. Another interesting fact I’ve learned is that because of an early sunrise, Assam’s tea gardens follow local time, known as ‘Tea Garden Time’ or Bagantime, which is an hour ahead of Indian Standard Time!

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Tea is grown in Assam during the summer season and in contrast to the UK, India has a much warmer and more humid climate during these months. However, the ambient temperature range for growing tea is approximately 13 – 30°C, which both Cornwall and Assam fall within the majority of the growing season. In fact, anything too hot and the tea leaves burn in the heat. Shade trees are often required in Assam to protect the bushes from direct sunlight. During the winter the tea bushes are dormant in both locations due to low temperatures and reduced daylight hours. There are many environmental factors which are important for optimal tea growth, such as temperature, moisture, soil depth and pH, and such conditions have both similarities and variation between Assam and England. Therefore, I wondered – do the growing conditions alter the taste?

The taste test
Clearly a tea taste test was in order to determine if nurturing tea plants in different geographical localities actually transfers a change in flavour through to the palette. I acquired some pure Assam loose black leaf tea from the Tocklai tea plantation and some classic black leaf tea bags from Tregothnan. Now, the black tea from Tregothnan is slightly misleading, as although marketed as “the tea grown in England” the bagged product is actually a blend of English tea with “finest Assam”, as stated on the front of their merchandise (if I ever acquire any pure English loose leaf tea I will re-do this taste test).

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Brewing the tea, I actually found the English tea to produce a darker brew. To me, the Assam tea tasted a little more bitter. There were certainly distinctive differences in the actual taste, but not being a qualified tea taster I’ve struggled to elaborate using the correct descriptive language. There are some top tips here though if you’re that way inclined. I tried both with and without milk and actually found both varieties of the tea very pleasant to drink black. Clearly both are winning brews and I’d recommend either, but I did particularly like the English blend taste. Views from others in a taste test stated the English variety to be “smooth and surprisingly strong”, “tastes quite powerful” and has “the nuttiness of a top Assam.” So if English grown tea is actually as good as Assamese tea for consumers, does the India to UK export industry have something to worry about?


Why grow tea in the UK?

In short, probably not any time soon. Tea is a lucrative business, we love a good cuppa, and the UK imports around £250 million worth of tea each year. English tea is not currently produced on a scale to rival Indian leaves, and probably never will be due to space issues. Tregothnan tea is presently marketed as a luxury brand but perhaps there is scope to plant further tea estates in the UK and cultivate more leaves on our home soil. In addition to a superb taste, a reason why this could be favoured by the UK community is largely environmental. Recent environmental concerns regarding more sustainable food production has led many consumers to think more closely about where the produce they are purchasing is being sourced. The slow food movement has gained traction over the last decade and people are beginning to care about reducing their environmental footprint. Checking your fruit and veg in the supermarket for where it originates from is one way to achieve this. Sourcing food locally and buying what is in season reduces an individual’s collective food miles; something the environmentally conscious are keen to achieve. I know I consistently check the origin of fresh produce and always try to buy British.

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So, by growing British and buying local, products can potentially be produced more sustainably and your environmental footprint is reduced. Perhaps this would be good enough reason to grow more of our nation’s favourite beverage on our home soil, as well as it tasting as good as our overseas tea rivals! However, tea is a way of life for many families in India and a decline in production could potentially be detrimental to their livelihoods; the international tea trade remains a significant factor in providing income for the people of Assam, but it’s good to know we can successfully cultivate tasty tea in England should productivity abroad ever decline.

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We are hoping to visit Tregothnan next summer to tour the tea estate in person and compare characteristics of tea bush cultivation between Assam and Cornwall. Another blog post will appear then, and perhaps we’ll get our hands on some non-blended pure English loose leaf tea to try.