8.6 Chemical Contamination

Chemical contamination occurs when excessive or inappropriate chemicals are used during resin induction. It reduces resin quality, affects aroma, and may lower market value, especially for incense or oil-grade agarwood.

1. What Is Chemical Contamination?

  • Definition: Presence of residues from salts, acids, oxidizers, or elicitors in the resin or wood that are toxic, off-flavored, or non-natural.
  • Purpose of Awareness:
    • Protect resin quality and aroma
    • Avoid market rejection
    • Ensure tree health and safety

More is not better — careful dosing is key.

2. Common Sources of Contamination

SourceEffect on ResinFarmer Observation
Salts (NaCl, KCl, MnCl₂)Alters natural aroma; can cause wood bleachingResin appears patchy, pale streaks
Acids (HCl, H₂SO₄, organic acids)Tissue necrosis, off-odorResin smells harsh or burnt
Oxidizers (H₂O₂, KMnO₄)Over-polymerization, chemical residuesResin hard and brittle; smell differs from natural agarwood
Excess chemical elicitorsToxic stress → tree weakeningLeaf drop, slowed growth, necrotic zones

3. Effects on Resin Quality

ParameterSafe UseOveruse / Contamination
AromaNatural, layered, sweet-spicyHarsh, chemical-like, unpleasant
ColorDeep brown to blackPale, patchy, bleached streaks
Oil ContentHigh, uniformReduced, uneven
Tree HealthMaintainedLeaf drop, branch dieback, slowed growth
Market ValuePremiumSignificantly reduced; may fail inspection

4. Farmer Tips to Avoid Contamination

✔ Use minimal, controlled doses of chemicals
✔ Prefer natural or mild elicitors when possible
✔ Avoid mixing multiple strong chemicals at high concentration
✔ Always record type, dose, and date of chemical application
✔ Monitor tree health and resin color/aroma regularly

Farmer Key Message

Chemicals can help, but too much harms.
Overuse changes aroma, reduces oil, and weakens the tree.
Controlled, moderate use preserves natural quality and market value.”