RUBBER NEWS

Techniques for Designing and Opening Rubber Tree Tapping Cuts

Posted on by content02.vinahugo
13
Oct

Designing the Upward Tapping Cut 

  1. Check Tree Standards

    • Use a measuring tape to inspect and mark trees that meet the tapping standard (Fig. VIII.4a).

    • All cuts in a plot must face the same direction, oriented toward the center of the row for easy inspection and management.

    • For contour planting, cuts face toward the inner contour line.

  2. Marking and Measurement Steps

    • Place a tapping ruler to mark the cutting line (ranh tiền), spout position, and hook location (Fig. VIII.4b).

    • Use a three-knot string to divide the trunk into two equal halves (Fig. VIII.4c).

    • Determine the rear boundary (ranh hậu) by making a vertical guide line on the trunk (Fig. VIII.4d).

    • Position the template (rập) along the front boundary to carve the standard tapping line and quarterly bark consumption lines (Fig. VIII.4e).

    • Use the consumption ruler to mark monthly wear lines at both front and rear boundaries (Fig. VIII.4f).

    • Carve the latex groove (mương tiền), 10–11 cm long, deep to the fine sandy bark layer — shaped “elephant head, mouse tail,” perpendicular to the ground (Fig. VIII.4g).

    • Equip the tree with full accessories after design (Fig. VIII.4h).

Designing the Downward Tapping Cut

  1. Orientation and Uniformity

    • Downward cuts within a plot must also face the same side for uniform inspection and management.

  2. Design Steps

    • Place the ruler and hook to mark the front line from 1.2–1.3 m above ground straight upward (Fig. VIII.5a).

    • Use a three-knot string or marked tape to divide the trunk into two parts (S/2) or four parts (S/4) (Fig. VIII.5b).

    • Determine the rear boundary with a vertical guide line (Fig. VIII.5c).

    • Place the template (rập) to carve the standard tapping line and monthly/quarterly wear lines between front and rear boundaries (Fig. VIII.5d–f).

    • The downward cut angle must be exactly 45° from the start — not gradually increased later.

    • Carve the latex groove (15 cm long) from the front line to the spout position, deep to the fine sandy bark layer, perpendicular to the ground (Fig. VIII.5g).

    • Equip the tree after completion (Fig. VIII.5h).

Additional Tapping Openings

  • In areas with distinct dry and rainy seasons, open additional cuts at:

    • The beginning of the tapping season and again in September–October each year.

    • In other regions: start of the season and again in August–September.

  • The height of new cuts must match existing ones.

  • By the third tapping year, all trees with trunk girth ≥ 40 cm at 1 m above ground should be opened.

  • In labor-scarce regions, staggered opening is allowed but must end by September each year.

Opening New Tapping Cuts

a. Upward Cut Opening

After design, open the cut with three knife strokes:

  1. First stroke – Standard cut (Fig. VIII.6a).

  2. Second stroke – Wedge trimming (Fig. VIII.6b).

  3. Third stroke – Finishing cut, gradually pressing the blade to the correct depth without damaging the cambium.

Then:

  • Carve the latex groove (Fig. VIII.6c).

  • Install the spout (Fig. VIII.6d).

  • Complete the cut (Fig. VIII.6e).

  • Fully equip the tree (Fig. VIII.6f).

b. Downward Cut Opening 

  • Similar three-stroke method, but cuts are upward-oriented.

  • Final depth: 1.1–1.3 mm above the cambium.

  • Optionally make 2–3 small downward cuts to form a latex flow guide (Fig. VIII.7e).

  • When rain shields are installed, add auxiliary channels to prevent latex spread.

  • Maximum bark removal: 2 cm for both cut types.

c. Re-Opening Old Cuts

  • For re-tapping existing trees:

    • Make two consecutive strokes — one to remove dry bark, one to re-shape the tapping cut.

    • Allowable bark removal: 0.5–1 cm.

    • Complete re-opening section by section.