Tree resin is a complex natural substance primarily composed of a mix of small organic molecules and a more complex polymeric structure.
Based on scientific understanding, plant resins consist of a mixture of small molecules of mono-, sesqui-, di-, tri-terpenoids and/or phenolic compounds, and a polymeric structure.
Understanding the Main Components
Tree resin is not a single compound but rather a diverse blend of organic materials produced by trees, often in response to injury. These components contribute to its sticky, aromatic, and protective properties.
The key components can be broadly categorized:
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Small Molecules: These are often volatile and contribute to the resin's aroma and initial fluidity.
- Terpenoids: A large class of organic chemicals derived from isoprene units. They are further classified by the number of isoprene units they contain:
- Monoterpenoids: (e.g., pinene, limonene) Consist of two isoprene units.
- Sesquiterpenoids: Consist of three isoprene units.
- Diterpenoids: Consist of four isoprene units.
- Triterpenoids: Consist of six isoprene units.
- Phenolic Compounds: Aromatic compounds containing a hydroxyl group directly attached to an aromatic hydrocarbon group.
- Terpenoids: A large class of organic chemicals derived from isoprene units. They are further classified by the number of isoprene units they contain:
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Polymeric Structure: This provides the more solid or semi-solid consistency of resin. It consists of larger, more stable molecules.
Composition Changes Over Time
The composition of resin can change significantly, especially during processes like fossilization. The reference highlights that during fossilization, most volatile components are lost and a polymerization process takes place. This means the small, volatile terpenoids and phenolic compounds decrease, while the polymeric structure becomes more dominant and interlinked, leading to the formation of substances like amber.
Why Do Trees Produce Resin?
Trees produce resin for several vital reasons, primarily as a defense mechanism:
- Protection against Insects: Resin can trap or deter insects that try to bore into the tree.
- Defense against Pathogens: It seals wounds, preventing entry of fungi and bacteria.
- Sealing Wounds: It acts like a natural bandage, helping the tree heal from physical damage.
In summary, tree resin is a dynamic mixture that serves essential protective functions for the tree, composed of various terpenoids, phenolic compounds, and a foundational polymeric structure.
