Tuesday, June 28, 2011

Cultivars, Monoculture, Adaptation, and Extinction: In Tea and Elsewhere

I was inspired to write this post after reading a post by Gingko Seto of Life in Teacup, about Long Jing Cultivars. I want to start by talking about the word cultivar because it is often thrown around without being precisely defined.

In the world of horticulture and agriculture, a cultivar is a plant or collection of plants that has been recognized for certain desirable characteristics. There are some cultivars which can be grown from seed, those that come up "true to seed", but many cultivars are cloned--propagated by cuttings or grafts. In the world of tea, as with wine, cultivars are also called varietals. Whereas "variety" is a general term that can refer to a broader style of tea, varietal is a more specific term, referring to the individual plant from which the tea was grown.

In the world of tea, varietals usually refer to genetically-identified plants propagated by cutting or grafting, but there are also broad categories of tea plants that come up true to seed, such as the smaller-leaved Chinese variety, C. sinensis sinensis, and the larger-leaved Assam variety, C. sinensis assamica.

Cultivar Extinction:

Most cloned cultivars, regardless of what plant they are from, eventually go extinct for ecological reasons: because they have a fixed genetic stock, the insects, mold, and bacteria in the world around them is constantly evolving and adapting to be better able to attack the specific combination of chemicals in the one cultivar.

This is why many of the old varieties of banana and apple, enjoyed by people a few generations back, are no longer grown: various blights and pests have developed which make them infeasible to commercially cultivate.

Why do we have so many old tea cultivars?

In the world of tea, we are left with many older cultivars. Why have they not gone extinct as most of the older varieties of apple have? One reason is that the tea plant, in general, is not particularly susceptible to pests, and the plant itself is very long-lived (some individual tea trees are themselves hundreds of years old). However, there is also another contributing factor, which is that, for hundreds of years, many of these cultivars were only cultivated on a small scale; below I will explain why this has prolonged the life of tea cultivars.

Some of the most popular cultivars are actually relative newcomers, compared to the long history of the tea plant. The varietal used to produce Tie Guan Yin emerged some time in the 18th century, although I've seen some sources claiming it was later. Either way, it is possible to find individual tea plants older than this particular cultivar.

Monoculture and its Role in Cultivar Extinction:

Monoculture is the widespread planting of a single crop, like tea, over a large area. Monoculture is widespread in tea cultivation, and is the norm for most commercial tea production, which is unfortunate for a variety of reasons. A long while ago, I wrote an extensive post about tea monoculture and monoculture in general which explains a number of negative impacts that monoculture has both on human agriculture and the surrounding ecology.

One of the main negative impacts of monoculture is that it facilitates pest and disease spreading. With no other plants to function as barriers or buffers, once a pest or disease gets established, it can rapidly spread through the whole crop. And with such a huge reservoir of a host plant, the pest or disease can quickly evolve and adapt by establishing a healthy, genetically diverse population of its own. Just as in my last post about the value of diversity, I explained how diversity is an essential ingredient in ecosystems. When two populations are competing in some ecological sense, the more diverse one typically wins the battle.

An extreme form of monoculture is the widespread planting of a single cultivar or varietal, over a broad area. When a single cultivar is grown in monoculture, the evolutionary pressure for pests and diseases to evolve or adapt to the particular cultivar or varietal is very strong. The pest or disease forms a huge, genetically-diverse population, but the crop being cultivated has no diversity, zero, as it all comes from a single plant that has been cloned, propagated by cuttings or grafts.

This is what causes cultivars to go extinct quickly. If a cultivar is only grown in moderation, and is grown only in small batches, mixed in with other crops, it will usually last for far longer; the risk of extinction by a pest or disease adapted specifically to that cultivar becomes minimal.

What can you do about this?

There are actually several ways you can help prevent monoculture. These tips are about tea, but they could easily be generalized to buying any type of plant-based product:

  • Pay attention to where your tea comes from, and give preference to operations that use ecologically sustainable methods. An example is Makaibari estate in Darjeeling, which leaves most of their land as intact forest and only cultivates a smaller portion of it. Seeking out the organic label is typically not enough to make the best choice; there are plenty of certified organic operations that are still monocultures, and plenty of more ecologically-friendly operations that are not organic certified.

  • Seek out and buy tea produced from different varietals. Varietals like Tie Guan Yin (to use an example) are so widely cultivated because people buy them for a high price. While it's hard to dispute that Tie Guan Yin produces amazing tea, there are numerous other cultivars that produce delicious tea as well, that go largely ignored on the global market. Try broadening your perspective: not only will you discover new teas, but you will be helping to preserve the most famous cultivars for future generations.

  • Returning to the topic of the original post that inpsired this one, which was Long Jing cultivars, don't malign or dismiss "fake" teas produced from different cultivars. For example, when tea in the style of Long Jing is produced from different cultivars, it helps to preserve and protect the original cultivars. If the original cultivars were grown on a wider scale, it would speed the development of pests and diseases targeting this cultivar, eventually leading to their extinction. These newer teas emulating an older style actually protect the "authentic" tea, rather than threatening it.

1 comment:

  1. Very thoughtful discussions from the ecosystem view! And the previous one on diversity is great too! I think this is another important aspect people can learn about the world through tea drinking, along with culture and taste appreciation.

    Cultivar extinction is significant. Recently I am studying on a guy who has saved thousands of important tea bushes (many of them are unique cultivars) in Wuyi mountain. But meantime, many hundred Wuyi cultivars are gone forever. Thinking this doesn't just happen for tea, but also apples, corns and a lot of other things globally, we should be really alerted!