Kris à Genève

A Canadian living in Switzerland

Rubber 101

with 2 comments

I have now completed two weeks of research in Binh Phuoc province of Vietnam. There were some bureaucratic hassles to begin, but these are to be expected in most countries in Asia, so I just twiddled my thumbs until it was all sorted, and things have gone smoothly since.

My research focuses on how families insert themselves into the rubber value chain in the province. This means that, following the rubber chain from seed to rubber tire, there are a number of activities families can access to earn an income, while others are off-limits to them. Further, some of these activities earn a higher proportion than others of the total value added on the chain. From my business background, I began the research feeling confident about the value chain approach, but I knew nothing about the process of producing rubber, which can not be separated from questions of value chains and incomes.

To overcome this shortcoming of mine, I worked into my interview questionnaire and my visits a sort of crash course for myself on how a farmer grows his trees, harvests his latex and sells it to be processed into rubber. For this blog entry I’ll ignore the actual topic of my research and see if I can explain rubber production – as much a test of my own understanding as a sharing exercise. Here goes:

The principal species of rubber tree in the world is hevea brasiliensis. As the name suggests, it originates from South America, where the bulk of rubber was grown in the 19th century. But in 1875, a sneaky Briton named Henry Wickham smuggled 70,000 seeds out of Brazil to London, eventually allowing the British to introduce rubber to their Asian colonies, as did the French and the Dutch. By the time of WWII, Asia was already an important rubber producing region, and since the war it has dominated world production. Today, 90%+ of world production comes from Thailand, Indonesia, Malaysia, India, Vietnam and China, in that order.

Agricultural engineers have continued to tinker with the species to improve its yields. So for example on the farms I have visited, the most common current varieties are coded PB260 and RIW4, both presumably from the original hevea brasiliensis stock.

The process begins when mature trees drop their seeds, which live in a cozy pod. The skins of the inner rubber seeds are often a shimmery pattern of brown, silver and gold.

The shell of the rubber seeds is too tough for plantation farming, i.e. not enough of them would sprout if planted as they are. Therefore the top of the seeds are split before planting. The following photo does not show a seed split at the top for planting, but a fully opened seed with its pulpy interior.

Nurseries plant the seeds in the shade and they sprout into spindly little saplings like this one:

This particular nurseries begins by planting a variety called GT1, grown for its sturdy root stock. But its latex production is low in quantity and rubber content, so when its trunk grows to approximately 1cm in diameter (about 7 months), it is grafted with the PB260 variety, which has a better balance of quantity and rubber content, but which on its own has a more fragile trunk and roots. Here are the GT1 saplings at grafting time:

Here is a sequence of photos showing a worker grafting the PB260 to the GT1 trunks. First he cuts a 1cm x 4cm slice from the GT1 trunk, then he removes a shaving of PB260 and then he ties it to the open section of the GT1 trunk using a little plastic ribbon. The grower then waits 10 days to see if the graft takes, after which time he removes the plastic ribbon and grows the tree for another month or so before preparing it for sale.

For the nursery shown in these photos, the saplings are ready to sell at 8.5-9 months. They offer two products: 1) stump tran, or “naked stump,” with an exposed root approximately 40cm in length, or 2) stump bou, a sapling grown in a little plastic sleeve. The survival rate of stump bou is much higher (97-8% compared to 87-8% for stump tran), and the price is close to double. Here is a photo of the nursery’s stock of stump bou, ready for sale at approximately $0.75 per tree:

The farmer buys these saplings, digs holes, plants them and then douses them in fertiliser. This first year is the major investment for a rubber farmer, as he must spend approximately $2,500 per hectare for trees, labour and fertiliser. He must then wait until years 4-7 (depending on variety and growth progress) to start extracting latex. Here is a photo of a plantation of approximately 3-year-old rubber trees:

There is a simple measure used to determine whether a tree is ready to tap: at 1-1.5m of height, the trunk must be 50cm in circumference. At that point, if the tree is otherwise healthy (no leaf or root diseases), the farmer begins tapping for latex. The low season is from March-May, then the high season runs from June-November. Most trees are planted in July, so their first cut is usually in July five years later. Since I arrived in late February – early March, many of the newly mature trees have just one half a year of cuts in them. Below is an example of the tapping setup, as well as of a tree with only a half year of cuts on it. The cut is a circular band on one side of the tree, at 35-45 degrees.

In the above photo, notice the guide marks scratched below last season’s cut. These guide the workers for the upcoming season, who will make a cut every two-three days. They use a simple little tool such as the following one to cut the tree:

Eventually the older plantations look like the following ones, with thick rubber trees, scarred by several years of tapping. The cuts go down one side for 5-6 years, then down the other. They can generally cut up and down each side twice, as the productive life of a rubber trees is 20-25 years. In the first photo, notice the coloured plastic sheaths above the cuts. They prevent rain from diluting the latex, which is bought on its rubber content.

Latex is sold in two forms to processing plants: 1) the white latex liquid collected every two days in the bowls shown in the photos above and 2) the coagulated bits of latex that drip down the tree or onto the ground and are recovered later in a solid form. The liquid form earns a better price and is paid in Dry Rubber Content (DRC). The families I have interviewed so far have trees that produce latex with a range of 28-38% DRC. Last year the price for 1% of DRC rose from VND 400 or so in April to VND 900 in December, so latex with 30% DRC earned VND 30,000 ($1.50) or so per kilogram at the end of the year – a record price.

Next are some photos from a processing plant we visited. Since we are not yet in the harvesting season, the plant was only processing the lower-value coagulate latex, not the liquid latex. First, here is a pile of dirty, stinky clumps of coagulate waiting to be shredded and washed:

The next photos show the latex being shredded, washed and then squeezed dry. Acid is the main chemical input and is added to the washing step. Thankfully, the washing process renders the stinky latex almost odour-free.

The latex is then arranged in racks of large rectangular pans for chemical treatment, cooking and cooling.

On the other side of the oven, three workers yank the cooled rubber blocks from their trays, place three of them together in a compactor, after which they are ready for packaging.

The following photos show the workers tagging and bagging the blocks with the SVR-10 grade, which is a low grade of rubber. Notice that it is black after coming through the oven. During latex season, this plant produces a higher-quality SVR-32 product, which is light orange in colour.

At the end of the process, you can see the raw material rubber that is so important to a variety of industries and is perhaps almost as prevalent in our economic lives as oil. This processing plant sells the majority of its products directly to customers in China. With prices at record highs, this means that, whatever the shortcomings of rubber cultivation (monoculture, clearing of forests), actors all along the value chain are enjoying good times, including family farmers such as Mr. Ba from the Tan Phuoc commune of Binh Phuoc province:

Lastly, I think it is important to issue a warning to anyone considering researching in rural areas of Vietnam. The leader of whatever village we are visiting often invites us for lunch. And rice wine is the traditional drink to welcome guests. The farmers love it and I like it too. But being the guest of honour means I have a glass of rice wine for only me, and the remainder of the men (no women usually) share a second glass. This means the guest of honour is encouraged to drink a succession of toasts with one diner at a time, effectively drinking twice as much as anyone else. I go slow as much as social propriety allows, but the farmers rarely accept “no” for an answer. Suffice it to say that my note-taking during the afternoons is less legible than in the morning.

In the last photo, the three fellows on the right are proud Communist Party members who immigrated many years ago from the North, a couple of them with military backgrounds. They spent the whole lunch, lubricated with rice wine, extolling to me the virtues of the Party’s leadership of Vietnam, leaving poor Thanh, whose family supported the old republican regimes in the south and whose perspective of Vietnam is “un-communist” (not necessarily anti-communist, but believing the Party plays only a small role in the country’s recent development), to translate their drunken boasting to me. Amusing for me; less so for him.


2 Responses

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  1. Great overview of rubber production. What is the difference in quality and uses of plantation rubber compared to petroleum based?

    Stafford Reid

    March 25, 2011 at 05:20

    • Hi Stafford

      Natural rubber is much stronger than synthetic. But natural is less water resistant than synthetic. These qualities mean that 60% of world production of natural rubber is used for vehicle tires. It is usually mixed with synthetic, with a higher proportion of natural for tires bearing heavier loads, such as for trucks, airplanes, etc. It is also used in surgical gloves and tubing, and condoms. Ciao.



      March 25, 2011 at 14:43

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