KAU Agri Infotech Portal

Rubber (Hevea brasiliensis)

Latex is obtained from the bark of the rubber tree by tapping, a process of controlled wounding during which thin shavings of bark are removed.
Both “Michie Golledge” knife used in India as well as the draw knife or ‘Jebong’ knife common in Malaysia are suitable for high and low level tapping and higher tasks.

The tapping cut of budded trees should have a slope of about 30o to the horizontal and for
seedling trees only about 25 o , since the fairly thick bark prevents spillage.
The latex vessels in the barn run at an angle of 3-5o to the right and therefore a cut from high left to low right will open more latex vessels.

Latex vessels are concentrated near the cambium.
Hence, high yield is obtained by tapping to a depth of less than one millimetre close to the cambium. Bark regeneration is brought about by the activity of the cambium.
Bark shaving thickness should vary depending on the frequency adopted.

Tapping should commence early in the morning as late tapping reduces the exudation of latex. Headlight can be used for visibility during early morning tapping.
Completion of tapping and latex flow in the early hours (02.00 to 6.00 hrs.) is good for higher yield.
It is particularly important during summer and in wind-prone areas.
The tapping task (number of trees tapped on a day by one tapper) in India is 300-400 trees.

Response to different tapping systems varies from clone to clone.
For high yielding clones (RRII 105, RRII 400 series clones, PB 260, PB 235 etc.), the trees are to be tapped on half spiral third daily (S/2 d3) system.
Alternate daily tapping can be practiced only for medium yielding clones (RRIM 600, GT 1, PB 28/59 etc.).

Low Frequency Tapping (LFT) with yield stimulation using ethephon (2-chloroethyl phosphonic acid) can be practiced from the first year of tapping to reduce the cost of tapping and increase productive life of trees and timber volume.
The LFT systems recommended are of d3, d4 or d7 frequency.

Controlled Upward Tapping (CUT) is a proven harvesting practice to achieve sustainable high yield for long term from old and senile trees.
The combination of Low Frequency Tapping with CUT from renewed panel stage can increase the economic life of trees up to 40 to 50 years.
In general 30-50 per cent higher yield can be obtained for many years under CUT.
The normal recommended CUT practice in India is periodic panel changing ie, basal panel tapping (S/2) with rain guard during rainy season, and CUT (S/4) on high panel during non- rainy season.
The length of tapping cut can be quarter spiral for CUT irrespective of the girth of tree and its slope should be 45 o .
For CUT, a modified long handled gouge knife must be used so that the tapper can stand on the ground and tap the high panel.
Tapping cut in the high panel can be stimulated using 5 per cent ethephon following lace application method.
For third daily (d3) tapping of quarter spiral cut in the high panel, monthly stimulation is enough for high yielding clones (like RRII 105) and stimulation at once in three weeks intervals is necessary for medium yielding clones.

A suitable device is fixed on the trunk just above the tapping cut and flow of water through the main trunk is channeled out.
This method is found to be effective to keep the tapping cut and the bark below and above in dry condition during the rainy season.
Chances of bark rot are high when the trees are rain guarded and tapping is continued during rainy season.
Irrespective of the type of rain guard used, regular panel washing using fungicide (mancozeb 0.37%) at 10-15 days interval is necessary to prevent incidence of panel diseases.
With the introduction of Low Frequency Tapping, rain guarding is needed even under low rainfall conditions.
Types of rain guards recommended are polythene skirt, tapping shade and Guardian/Kissan rain guard.