Natural rubber comes from the milky latex of the Hevea rubber tree, collected by cutting a shallow channel in the bark and catching the drips in a cup. A mature tree gives 30-80 mL of latex per tapping and 2-5 kg of dry rubber a year, so a village that needs 100 kg a year must tap between 20 and 50 trees. Latex starts to spoil within hours of leaving the tree, so it must be coagulated or preserved the same day.
Part of Rubber Processing
Where raw rubber comes from, how much a tree gives and what has to be done before it spoils.
Rubber Starts As A Perishable Liquid From A Tropical Tree
Hevea brasiliensis grows in tropical climates, within 15° of the equator and with 2,000 mm or more of rainfall, according to the carrier article. The corpus’s Dandelion Rubber article gives a tighter range, about 10 degrees of the equator; the two do not agree, so treat 10-15° as the margin and check against local trees. Outside that belt, the alternatives are in Alternative Rubber Sources.
Latex is a milky suspension of rubber particles in water, and the carrier gives 30-80 mL per tapping. It is not rubber yet. Left alone it sours and clots into a foul mass within hours, as the corpus’s Coagulation article says, and the Latex Processing article sets the working limit: coagulate within 4-6 hours of collection.
What You Need
- Trees: mature Hevea, with the bark channel cut as described in Tree Tapping Technique.
- A sharp hooked tapping knife, a spout of sheet metal or bamboo, and a cup for each tree.
- A strainer and clean buckets for the latex; see Latex Collection and Preservation.
- A decision, made before the first cut, about what the latex will become: sheet, crepe, or dipped goods.
Method: From Tree To Bucket
Step 1: Tap early. The tapping article puts the best time at 4-7 AM, when pressure in the bark is highest.
Step 2: Collect by mid-morning. Latex flows for 3-4 hours after cutting, per the carrier.
Step 3: Strain and pool the cups into one bucket and process the same day.
Step 4: Coagulate or preserve. See Acid Coagulation.
Worked Example
The carrier gives 2-5 kg dry rubber per tree per year. The tapping article gives 15-30 g of dry rubber per tapping on an alternate-day schedule, which is about 365 ÷ 2 ≈ 182 tappings a year: 182 × 15 g = 2.7 kg and 182 × 30 g = 5.5 kg. That is consistent with the carrier’s 2-5 kg.
Trees for a target: 100 kg ÷ 5 kg per tree = 20 trees, and 100 kg ÷ 2 kg per tree = 50 trees. The 20-50 range is the honest planning range, and it counts only mature productive trees.
Common Mistakes
- Collecting but not processing. A full bucket left overnight is lost.
- Cutting too deep. The carrier and the tapping article both warn that damaging the tree’s growing layer kills it, though they give different cut depths; follow the tapping article’s test of white wet tissue.
- Tapping every day. The tapping article reports only 20-30% more latex than alternate days at a large cost in tree life.
Safety
Tapping knife and latex allergy
A hooked tapping knife is razor sharp and is swung at arm’s length against a tree; keep it sheathed when walking. Fresh latex contains proteins that cause allergic reactions in some people, ranging from a rash to breathing difficulty (recalled general fact, not from the corpus). Anyone who develops itching, hives or wheeze when handling latex should stop handling it and not wear latex gloves.
What’s Next
- Learn next: Tree Tapping Technique — making and keeping the cut
- Combine with: Acid Coagulation — turning the liquid into rubber