By Kathy Sadowski, MS in Aromatherapy, RA, LMT

Trees: Strong, nurturing, and ever enduring. They are the heart of the jungle, the canopy of the forest, and the home and nourishment to millions of plant and animal species. Trees are sacred, beloved, and necessary for all life on earth.

Naturally, many aromatic and medicinal products originate from the leaves, flowers, seeds, bark, branches, heartwood, resin, and gum resin of trees. 

The resin and gum symbolize the life force that oozes out from a tree’s bark or stems. This article discusses those resins and gums, answering the question: What is the difference between resins and gums? Further, the following terms are reviewed in detail: Gum resin, sap, and resinoids. 

The amazing aromas that can be found in resins and gum resins are a true delight. However, there are several species that produce aromatic resins that have become threatened. As a professional aromatherapist and an “impactful consumer,” it is important to be aware of unsustainable essential oil species.

What is a Resin?

A resin is the sticky ooze exuding from the tree, predominantly those of the Pinaceae family.  Resins are formed as an oxidation by-product of essential oils, and expelled out of a tree’s bark, hardening with exposure to air.¹ Trees are typically tapped to acquire enough amounts of resins for commercial use. 

Resin is insoluble in water, but dissolves in alcohol and other solvents.¹ It is used in industry to make glues, waterproof varnishes, and in aromatic/medicinal products. 

Types of Resins

There are three groups of resins: Hard resins, oleoresins, and gum resins.

Hard resins contain very little essential oil and are used to make varnishes and adhesives.¹ Amber is an unusual hard aromatic fossil resin, typically originating from a pine tree. Sometimes ancient remains of plants and animals can be found in amber resin.²

Oleoresins are typically liquid and contain significant amounts of essential oil. Oleoresins include turpentine, balsam, benzoin, elemi, and copaiba.¹ 

• Turpentine comes mainly from coniferous trees, which exude a substance called pitch, tapped for commercial harvest. Trees of the Pinaceae family include cedar, pine, fir, spruce, and hemlock.³ Note that multiple essential oils come from trees of the Pinaceae family, but may come from other plant material, such as the needles or cones, and not necessarily from the resin.

Examples include:

• Pine (Pinus sylvestris)
• Fir (Abies balsamea)
• Black spruce (Picea nigra).
• Balsams are aromatic oleoresins containing benzole or cinnamic acid. Essential oils can be extracted via distillation. Contradictory to what the general name might apply, balsams do not actually include Canada balsam (Abies balsamea) or copaiba balsam (Copaifera officinalis).¹ Balsams do include the following trees, belonging to the Fabaceae family:
  • Balsam of Peru (Myroxylon pereirae)
  • Balsam of Tolu (Myroxylon balsamum).
• Benzoin is a thick gooey substance with a fixative quality and vanilla aroma. It comes from plants of the Styrax family, including:
  • Sumatra benzoin (Styrax benzoin).
  • Siam benzoin (Styrax tonkinensis)
• Elemi (Canarium luzonicum) differs from other oleoresins in that the substance is not liquid. It hardens with air exposure.¹ 
• Copaiba includes aromatic oleoresin mostly from the Copaifera species of the Fabaceae family of South America. Copaiba is obtained by boring holes into the heartwood.¹ 

What is a Gum?

Gums are made by plants when internal tissue decomposes. This process, called gummosis, creates a product high in sugar. Gum typically oozes from stems or branches in response to a wound. It is created by the plant to prevent fungal infection. Plant examples include:

• Gum acacia (Acacia senegal)
• Gum tragacanth milkvetch (Astragalus gummifer)
• Indian tragacanth (Sterculia urens)
• Prunus ssp.¹   

What is Sap?

Note that resins and gums are different from sap. Sap runs through the xylem and phloem of trees to provide water and nutrients in a process called transpiration.⁴ Resin, found in the resin ducts of a tree’s bark, protects the tree from injury, water loss, microbial pathogens, and insects.⁵

A Mix: Gum Resins

Gum resins are a mix of gum and resin and can also include essential oils. This substance is typically collected by tapping into a tree. Gum resins typically come from trees of a dry climate, such as those of the Burseraceae family. Examples include:

• Frankincense (Boswellia ssp.)
• Myrrh (Commiphora myrrha, Commiphora erythraea).

Table Summarizing Resin, Gum, and Gum Resin

	Resin	Gum	Gum Resin
Definition	Usually oozes out of bark.	Usually oozes out of stems.	Combination of gum and resin.
Water Soluble	No.	Yes.	Partially.
Alcohol Soluble	Yes.	No.	Mostly.
Examples	Pine, fir, spruce, true balsams, benzoin, copaiba, elemi.	Gum acacia, Gum tragacanth milkvetch, Indian tragacanth, Prunus ssp.	Frankincense, myrrh.

What is a Resinoid?

A resinoid is an extraction from resinous plant material using a solvent. It is less volatile than essential oil, and often used in perfumery as a fixative.

A Final Thought…

Resins and gum resins used in aromatherapy, tapped from trees, may sometimes be overharvested. This can lead to species becoming threatened or endangered. Further, excessive tree destruction can lead to the loss of habitat for many other plant and animal species.

Below is a list of examples of species producing resins and gum resins that are included on the IUCN Red List of Threatened Species.⁶ The International Union for Conservation of Nature’s Red List of Threatened Species is the world’s most comprehensive information source for threatened plant, fungi, and animal species:⁶

• Frankincense, multiple Boswellia ssp.

• Myrrh, multiple Commiphora ssp.
• Elemi (Canarium luzonicum)
• Copaiba (Copaifera paupera and Copaifera glycycarpa)
• Benzoin, multiple Styrax ssp.

When considering the purchase of an essential oil, it is always good to know if the species is threatened. If you are unsure, it is easy to go to the IUCN Red List of Threatened Species website. Then, do a quick search by Latin name in the search box at the top of the home page.

Editor’s Note: It is important to check the full plant species name, in addition to just the general Genus, as individual species may not currently be listed; for example, Commiphora myrrha. In addition, some species commonly used in aromatherapy for essential oils may be sustainably harvested or grown rather than wild harvested or unsustainably grown or harvested.

Cinnamon Pinecones

Ingredients and Supplies:

• crock pot
• rubber gloves
• 6 medium pine cones
• 1/2 cup of water
• 1 tsp. dish soap

Essential Oils:

• 10 drops cinnamon (Cinnamomum zeylanicum)
• 10 drops of pine (Pinus sylvestris)

Directions for Making: Combine the dish soap and water. Dampen the pinecones with the soapy water. Heat the pinecones in crockpot on low heat for 90 minutes to kill any bugs from outside and to help the pinecones open up. Turn off the crock pot. Wearing rubber gloves, sprinkle the pinecones with the essential oils. 

Instructions for Use: Place in a decorative bowl for winter cheer or wrap a ribbon around the cone to hang on a tree for the festive season.

Cautions: Keep out of reach of pets and children.

Cinnamon Rosemary Aromatic Ornaments

Ingredients and Supplies:

• 2 cinnamon sticks
• 2 rosemary sprigs
• ribbon
• rubber gloves

Directions for Making: Wear rubber gloves to wrap the cinnamon sticks and rosemary springs together using a decorative ribbon.

Instructions for Use: Hang in a doorway for winter cheer and aroma or hang on a tree for the festive season.

Cautions: Keep out of reach of pets and children.

References

1. Legner, E.F., (n.d.) Discoveries in Natural History & Exploration. Gums & Resins. (The University of California, Riverside).  Accessed October 8, 2019 from: https://faculty.ucr.edu/https://faculty.ucr.edu/~legneref/botany/gumresin.htm
2. Encyclopedia Britannica, (10/2/2019), Amber, accessed October 11, 209 from:  https://www.britannica.com/science/amber
3. Elpel, T. (2018), Botany in a Day: The Patterns Method of Plant Identification, Hops.
4. Encyclopedia Britannica, (n.d.) Transpiration, accessed October 11, 2019 from: https://www.britannica.com/science/transpiration
5. Miller, D., (5/9/18) The Difference Between Tree Sap & Tree Resin. sciencing.com, accessed October 8, 2019 from https://sciencing.com/difference-between-tree-sap-tree-resin-12296179.html
6. IUCN Red List of Threatened Species (2019), accessed October 11, 2019 from: https://www.iucnredlist.org/

About Kathy Sadoswki:

Kathy Sadowski has a Master of Science degree in Aromatherapy from the American College of Healthcare Sciences. With a passion for reading scientific studies on herbs and essential oils, she has developed the website www.EarthtoKathy.com, which categorizes 4,000 plus scientific research articles on plants by species, therapeutic action, and constituent. The goal is to demonstrate a growing amount of evidence for the potential healthful uses of herbs and essential oils.  Kathy is a professional member of NAHA and AIA, a Registered Aromatherapist (ARC), licensed massage therapist, and enthusiast for environmental protection and a natural lifestyle. Visit Kathy’s website at: www.EarthtoKathy.com

 

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