3.1 Mechanical Wounding Methods: Drilling, Nailing, Bark Removal

Mechanical wounding is the first step in triggering resin, and there are three common approaches. Each has its purpose, advantages, and risks.

Drilling (Most Common & Controlled)

What It Is:

  • Small holes are drilled into the trunk or branches.

Purpose:

  • Opens the wood for microbial entry
  • Triggers the tree’s wound response

Farmer Guidelines:

  • Hole depth: 2–3 cm
  • Hole diameter: 5–8 mm
  • Spacing: 10–15 cm apart
  • Height: 30–150 cm from ground
  • Use clean, sharp drill bits

Benefits:
✔ Controlled and precise
✔ Minimal tree damage if done correctly

Risks:
✘ Too many holes → vascular blockage → tree death
✘ Deep drilling → kills inner wood

Nailing

What It Is:

  • Iron or wooden nails hammered into the trunk.

Purpose:

  • Creates small injury points
  • Adds long-term irritation (rust, minor infection)

Benefits:
✔ Easy and inexpensive
✔ Continuous stress if nails are left in place

Risks:
✘ Hard to control depth
✘ Can damage tree if too many nails
✘ May complicate future harvesting

Bark Removal / Stripping

What It Is:

  • Small sections of bark are removed from the trunk or branch.

Purpose:

  • Exposes cambium (living layer)
  • Directly stresses the tree
  • Allows natural microbes to enter

Benefits:
✔ Exposes more wood for microbial invasion

Risks:
✘ High chance of infection
✘ Can kill tree if overdone
✘ Leaves large scars → weakens tree

Comparison Table (Farmer-Friendly)

MethodControlResin ResponseRisk
DrillingHighMedium–HighLow–Medium
NailingMediumMediumMedium
Bark RemovalLowMedium–HighHigh

Farmer Tips for Mechanical Wounding

✔ Always start with healthy trees
✔ Do not combine all methods excessively
✔ Use clean tools to prevent unwanted infection
✔ Combine wounding with microbial inoculation or chemical elicitors for best results
✔ Leave time for resin to develop before checking

Farmer Key Message

“Wounding starts the process — but care and patience create valuable resin.”