Protecting the Traditions and History of “Uji Tea” by Utilizing Weather Data

Date of interview

October 16, 2020

Targets

Kazunobu Okadome, Senior Researcher, Tea Industry Research Division, Agriculture and Forestry Technology Department, Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center Eiichi Kiwayama, Councilor, Kyoto Tea Cooperative Koji Totsuka, Deputy Director, Chamber of Kyoto Prefecture Tea Public Interest Incorporated Association Sachi Hanada, Ujicha Branding Association (Specified Nonprofit Corporation Global Futures Kyoto)

Please tell us about the characteristics of Uji Tea production in Kyoto Prefecture.

Mr. Totsuka: It is probably that Kyoto produces multiple types. We have the strength in having created Matcha (powdered tea), Sencha (green leaf tea), and Gyokuro (refined green tea), which are the three representative types of green tea in Japan.

Mr. Kiwayama: In the case of Uji, various different tea products are produced in small units with strict fertility management and are sent to the market instead of mass production in large lots. These are then used as raw materials that are blended in various combinations to create teas of tastes with very rich individuality that make the most of each tea leaf. I believe this is the characteristic of Uji that has been passed down over generations.
Half of whether the tea tastes good or not is determined by cultivation. The other half is determined by the finishing technique. It will not result in a high value unless both are excellent, not just either one. The basic work is done by the producer up to the stage where the form of tea is realized in what is called “Aracha (unprocessed tea).” Then the traditional wholesalers purchase these tea products and blend them, but they maintain the same taste and flavor every year, no matter what the conditions are. Since tea is an agricultural crop, the taste varies depending on the climate of the year. However, they are able to maintain the same quality because they have excellent finishing and blending techniques. The ability of appraisal to form a product by determining the blending proportion while checking the tastes of various different tea products that are on the market is a traditional technique.

Did Uji become a major production area for tea because the climate was appropriate?

Mr. Okadome: The history of Uji Tea began approximately 800 years ago. Since we have a relatively large annual rainfall of 1500 mm and the Uji River in the area in addition to the soil property with good drainage, it was geographically appropriate for tea production.

Mr. Totsuka: There is also that we have frequent occurrence of fog. Morning fogs prevent frosts. Although the Kyoto Basin, which is lowest in elevation in this area, has the Uji River and is now a reclaimed land which is mostly used for rice paddies, it was said that fog was generated often as the river water flowed into a large pond called Ogura Pond.
I believe the facts that it was close to the locations of tea consumption such as the Imperial Court and shogun family, and that powdered tea from Uji was used in the development of tea ceremony were also important factors in addition to the climate. There must have been an atmosphere among the producers to work hard and produce good tea in order to offer it to the shogun family. That an ancient capital Kyoto had a lot of night soil, which had been used as a fertilizer in the past, and it could be transported on Ogura Pond seems to have been a factor as well.

Mr. Kiwayama: They also had plenty of wild reed, which was used for sunshade. Although different materials are now used, they used to shade the sun by building a frame with logs as poles, bamboo as beams, and ropes made of straw tying them together, and using reed screens and straws as the shade.

Mr. Totsuka: Green leaf tea and refined green tea were created in the process of evolution from powdered tea due to complex reasons. I feel that they really express the characteristics of production area for Uji Tea.

The first meteorological observation device was installed in 2015. Were there opinions from the producers that they were observing impacts of climate change at that time?

Mr. Totsuka: Yes. It was installed in the first place because the climate change was so dramatic that even the most experienced tea farmers could no longer make predictions. One of the reasons was that the experience no longer worked as the climate change was too drastic, even though they had cultivated tea based on experience to some extent until now. The most important factors for tea growth are the air temperature and rain, and we currently use the average air temperature for our model. We are conducting analysis to improve the accuracy, as we also expect other factors to be involved.

How do you predict the optimal timing for tea plucking, etc.?

Mr. Okadome: As an effort by the Ujicha Branding Association, meteorological observation devices were installed at 13 points of the production area. While we had already been making pest occurrence prediction, etc., we included air temperature prediction on a 50 m grid square air temperature map starting in 2020 to estimate the cumulative temperature for each tea plantation and predict the growth, timing for tea plucking, etc.
Each producer had judged the work sequence for each tea plantation based on the growth of the shoots, experience, and hunch before. However, this made it difficult for new farmers and employed workers to determine the timing for plucking, possibly resulting in reduced income or decreased quality as they cannot harvest at the optimal timing. By enabling prediction of changes in air temperature, etc. for each tea plantation, it has become possible to accurately calculate the optimal timing for plucking.

Ms. Hanada: The meteorological observation device is capable of measuring a total of 12 items, including the air temperature, wind speed, wind direction, atmospheric pressure, humidity, solar radiation intensity, precipitation, ultraviolet quantity, soil temperature, and soil moisture.

Mr. Totsuka: The temperature may vary on sloped lands, and there may be multiple producers within a 50 m square. We therefore feel the necessity to make pin-point observations with actual measurement values.

Mr. Okadome: The system to predict in a 50 m square grid unit that I mentioned earlier is called the “Tea Growth, etc. Prediction Mapping System,” and it is basically a system that individuals can utilize via smartphones to help in production. It has 4 functions of frost prediction, prediction of optimal timing for tea plucking, prediction of optimal timing for insect pest control, and changes in air temperature. Although it is still in test operation stage today, we are collecting data and modifying the prediction formulae to improve the precision and start full operation in 2022 or later.

Has it advanced enough to allow the producers to actually utilize the data in cultivation?

Mr. Okadome: Since we do receive requests from producers to “make it this way and that,” I am sure they are at least using the data as reference. Although the Tea Production Prediction Mapping System is still in test operation, we are continuing development to start full operation in 2022.

Mr. Totsuka: Since the optimal timing for plucking varies by the type of tea, such as powdered green tea (Tencha) which is the raw material for powdered tea, and refined green tea, the one that suits the type of tea must be applied if they want to utilize the data. A remaining issue is that growth also varies slightly by the breed.

Finally, please tell us about the sense of satisfaction in your job and future prospects.

Mr. Okadome: The techniques to produce top-quality tea must be succeeded to the later generations, and I hope to conduct research so that they can be transmitted using technology such as information and communications technology (ICT) in the future. Since it has recently become difficult even for the most experienced producers to predict the weather, I hope to achieve response to the climate change while also borrowing resources from the national government.

Mr. Kiwayama: These days, when many people do not know the taste of tea, I feel that we must promote so that they learn the taste of tea and create the needs for tea with better taste. As the Kyoto Tea Cooperative, we must also manage to protect the brand of Uji Tea. I feel the sense of satisfaction in conducting these activities.

Mr. Totsuka: I was able to take a look at the journals the producers were keeping when it was decided that we would install meteorological observation devices, but a lot still remain analog. Since the meteorological observation devices accumulate digital data, it will be easier to produce good tea in the future once they are combined and passed down to the next generation. While I feel that the tea industry will not survive unless we focus more on export as well, I believe it is essential that the data on cultivation conditions, fertility management, agricultural chemicals, etc. are accumulated and utilized in order to securely promote exporting. I hope that we will be able to provide support to such issues.

Ms. Hanada: I belong to a specified nonprofit corporation called “Global Futures Kyoto,” and the chief director of this organization is a Sri Lankan. You probably know that Sri Lanka is a globally famous producer of tea, but many tea plantations there fell into ruin due to climate change. The idea “We must prevent the same situation from happening in the production area for the famous tea in Japan,” became a trigger to gather concerned parties and start this project.
Although we cannot avoid climate change, I continue working to respond to it to protect the traditions, history, and the brand of Uji Tea and “be of help to contribute to the succession to the next generation with digital technology.”