Trees, Harvesting & Processing Latex

This post gives an overview of rubber processing.

1/2 coconut shell is the commonly seen container used to catch the dripping latex from rubber trees.

Because there are a lot of coconuts in Jambi, a ½ shell is almost always used to collect the latex. The shell is either placed on the ground or propped against the tree with a 3-5’ branch that has a “Y” on the end of it.

The trees are cut diagonally, which opens the bark and allows the latex to flow down and out onto a metal spout that has been inserted into the tree’s bark. From there the latex drips into the coconut shell.

New cuts on trees usually take place during early morning hours. A good harvester can make a new cut in 20 seconds, and daily they can cut between 450-650 trees.

There are many variations in the frequency and length of cuts. The harvester must use caution so as not to cut too deeply into the tree, beyond the bark, or the renewing bark will become deformed. Damaged bark will hinder the same location on the tree from being able to be cut into in the future. The same section on a tree can be tapped 2-3 times during the life of a tree. It’s usually 7 years before the same section of the tree can be tapped again.

Our post of rubber’s history in Jambi can be read by clicking this link.

Questions and Answers

Leaf and a piece of metal used to direct the flow of latex into the coconut.

How long does it take from the time a seed is planted until a seedling is ready to be replanted in a field?

  • From the time the seed sprouts, until replanting, is around 4 months. Trees are planted 16’ apart and 8 feet between rows.

What is the cost of one of these seedlings?

  • A certified grafted seedling is Rp4.500,00 each ($0.46 USD).
  • A certified seedling that has one branch growing off of it is Rp7.500 each ($0.80 USD).
  • A certified seedling that has two branches growing off of it is Rp8.500 each ($0.90 USD).

Latex in the field is collected and formed into large blocks. The sizes of the blocks vary, but are around 3′ x 6′. This truck is transporting the blocks to the processing facility.

How long must you wait from the time a seedling is planted until the time the tree can be tapped?

  • Normal length of time is 6-7 years. The size of the tree trunk is the indicator.

The specially shaped knife is making a thin cut into the bark to open the “pores” so the latex can flow again. This cutting takes place every other day, or every 3 days.

For one tree, how many times can a fresh cut be made in a tree to release the latex?

  • Every 2-3 days. Some people do it every other day.

Typically how long does it take to fill the ½ coconut shells with latex.

  • During a good season it usually takes 2 days and nights.

How is the latex formed into the rectangle form that is commonly seen when it’s transported from the fields to the processing facilities?

  • Ammonia is added to the latex to make it formable. The latex is poured into 3’ x 6’ rectangular molds, then left to solidify. After that they are shipped to the processing factories.

How much is 1 kilogram of latex, and what will influence its value?

  • The Jambi Independent newspaper on July 10, 2012, said the value was  Rp23.700 ($2.47 USD)—24.700 ($2.58 USD) per kilogram.
  • The cleaner the latex the more valuable it is. If it’s noticeable that there are leaves, sticks, stones, etc., in it, the price will go down accordingly (there have been cases when farmers would try to put dead monkeys and anything with weight into a block of latex to add to its weight).

Women are also used in rubber harvesting.

How long can a tree be expected to produce latex?

  • A tree that has been grafted will produce for 25 years.
  • A naturally grown tree can produce for as long as 35-40 years.

Can the wood from a rubber tree be used in construction?

  • Yes. It’s usually used to make plywood. It can also be used to burn for cooking fuel.

How do the rubber factories take the latex blocks and prepare it for drying?

Rubber hung to dry at the Hok Tong rubber processing facility.

  • At the factories the rubber is rolled to remove water, then rolled again to help add texture. The rolling forms very long 1 inch thick and 3 foot wide bands.
  • The long bands are then hung in the “smoke rooms” and heat is applied from below to dry them out. The heat for this is derived from burning rubber tree logs.

Rubber sheets hanging to dry at the Hok Tong rubber processing facility.

  • It usually takes 5 days for the bands of rubber to become dry. After that the rubber is shipped down river to factories that will make the products they need.

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Home Processing

Jambi rubber farmers don’t process the latex themselves. They send it to the local factories where that work is done. The below Youtube videos shows harvesters in other countries that process the rubber themselves.

Rubber hanging to dry at a processing facility on the north side of the Batanghari River in the City of Jambi.

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