I avoid saying that I love trees. That sems too trite, and it sounds blasé… because everyone “loves” trees; it says so on their t-shirts. So I choose other words like fascinated, inspired, excited. To me, there really is something magical and spiritual about walking through a forest filled with trees that are hundreds of years old. There is a sense of life that permeates the air in even the stillest of forests. There is a fair amount of quality research being released in recent years about how trees communicate. Yes, trees actually do communicate with each other in the forest although I have not seen any credible evidence for sentience in trees, and maybe this is really a topic for another article. Ultimately, I believe that there is a point of balance between using trees for our benefit and treating them with respect. I have no problem with utilizing the products that trees provide us. Trees can truly provide a sustainable supply of many things useful for humans. Trees can even be part of a regenerative agriculture, where the air, water, soil, and ecology as a whole are improved while we still collect a harvest. But if we do not respect the trees, and the ecology surrounding them, our endeavors will be destructive and degrading. Trees cannot be treated like so many things in our modern throw-away society.

With that said, there are so many products that trees provide, in their living and, yes, even in their dying. Most people are well familiar with the fruits and nuts that living trees provide. Dead trees provide firewood, building wood, and even food for certain medicinal and edible mushrooms. There are a number of trees that can be tapped to provide sweet sap that can be reduced to a tasty syrup. The most notable are the maple species, although there are actually a number of other species that can provide a good, but lower quality syrup than the maples.

I want to address another product that can be obtained from tapping trees, but it is not for their sap. It is for their resin. Resin is obtained from many trees other than the pines, but that is the most common resin-producing tree in my local Temperate Climate.

We see a pine tree and we think Christmas trees, pine cones, wood, and maybe paper. A few of us think about pine nuts… delicious! There are probably a few of us who think about a tea made from pine needles that is high in vitamin C and was used to prevent scurvy in long Winters without fresh fruits and vegetables. Those with some land may consider them as good trees for windbreaks. But how many of us see a pine tree and think of turpentine, rosins (for bowed string instruments, gymnists, ballet dancers, baseball pitchers, etc.), varnish, oil-paint thinner, furniture wax, lamp oil, soap, tar, and pitch?

In modern times, many of these products are now made with synthetic chemical processes that can be highly polluting and is typically unsustainable. As a Permaculturist, I am very interested in learning more about traditional products, their collection, processing, and uses. The remainder of this article provides an overview of the science, history, collection, and uses of resin.

 

Resins_05

Pine Resin is naturally produced from wounds on the tree.

Resins

Resin is a fluid (specifically, a hydrocarbon) that is secreted from certain plants (a.k.a. resinous plants), most commonly trees, and most commonly coniferous trees such as pine trees. Resins perform a number of functions in the plants that produce them. Resins seal over wounds, and this protects the plant from pests and infections. Resins contain antimicrobial properties that help prevent decay and fungal infections, and resins also seem to decrease water loss during droughts or plant injury.

Humans have gathered and used resins from plants for thousands of years. Resins have been used for waterproofing, varnishes, adhesives, art, incense, medicines, and many other purposes. It is only recently in human history that we have started using synthetic, as opposed to  natural/plant-derived, resins.

Resins_04

Historic photo from Florida’s pine-tapping turpentine industry.

Another historic photo from Florida's pine-tapping turpentine industry.

Another historic photo from Florida’s pine-tapping turpentine industry.

Another pine resin collection device.

Another pine resin collection device.

Resins can be collected by tapping trees. This has traditionally been achieved by notching the bark in a parallel V-shaped pattern. At the lowest notching, a bucket collects the pooled resin. Trees can be tapped for well over 20 years, and are then used for other purposes including timber, since the wood is not damaged during the tapping process. Depending on the species of tree and the product desired, various processing techniques are used to refine the resin.

While all resinous plants produce resin, some species and hybrids produce higher quality resin than others. Trees also produce other fluids (e.g. sap, latex, gums, etc.), but these are chemically quite distinct from resin. Resins can be categorized a few ways, and while I think the following is a pretty good system, there is a fair amount of overlap between categories:

Mastic

Mastic

Hard Resins: These are, not surprisingly, hard. Here are some examples of hard resins:

    • Dammar – obtained from the Dipterocarpaceae family of lowland, tropical rainforest trees from around the globe and the Agathis trees of  southeast Asia and northern Australia. Dammar is used as a glaze for foods, crafts, incense, varnish, and more.
    • Mastic – obtained from the Mediterranean Mastic Tree (Pistacia lentiscus). Mastic was commonly used as a natural chewing gum, but it is also used in ice creams, puddings, pastries, nougat, sauces, soups, fruit and vegetable preserves, soft drinks, coffee, liqueurs, and many other foods. It has a long history as a medicinal and incense, and is also used in perfumes and cosmetics and even in varnishes.
    • Sandarac – obtained from the Sandarac Tree (Tetraclinis articulata) of North Africa in a dry, Mediterranean climate. Sandarac is used for varnish and lacquer.
Elemi resin ready to be harvested.

Elemi resin ready to be harvested.

Oleoresins: These are resins that contain an oil component naturally made by the tree. They typically stay soft or gum-like. Here are some examples of oleoresins:

    • Balsams – obtained from a variety of trees and shrubs. Balsams contain certain esters (e.g. benzoic or cinnamic acid) that are aromatic, and therefore, balsam is commonly used for as a fragrance and a traditional medicine.
    • Copaiba – obtained from the Copaifera genus of leguminous trees of South America. Used in varnishes and lacquers.
    • Elemi – obtained from the Elemi Tree (Canarium luzonicum) tree of the Philippines. Used in varnishes, lacquers, and traditional medicine.
    • Labdanum – obtained from the Rockrose (Cistus species) from the Mediterranean. Used in traditional medicine and perfumes.
    • High-Terpene Resins – obtained most commonly from Pine Trees (Pinus species). See Turpentine below for more detailed information.
Frankincense

Frankincense

Gum Resins: resins that are produced with a natural gum (sugars/polysaccharides) instead of oil. Here are some examples of gum resins:

    • Frankincense – obtained from the Boswellia genus of trees from tropical Africa and Asia. Used as an incense, perfume, medicinal, and had many religious ties.
    • Guggal – obtained from the Guggal Tree (Commiphora wightii) of North Africa and central Asia. Used as a traditional medicine.
    • Myrrh – obtained from the Commiphora genus of tree of tropical Africa, Asia, and South America. Used as a fragrance and medicinal.
Amber with a trapped insect.

Amber with a trapped insect.

Fossilized Resins:

    • Amber – the color “amber” is named after this amber-colored plant resin that has fossilized, although there is a blue amber that is stunning. Amber sometime contains animals or insects and is used in paleontology. Amber is used in jewelry, traditional medicine, perfumes, incense, varnishes, and lacquers.
    • Copal – this is a resin that has not quite been fossilized yet, so it can be considered a resin that is on its way to become an amber. It has been used as incense and medicine and varnish.

 

 

The Loblolly Pine is commonly used for timber, phone poles, and paper, but is a high-terpene producing resin plant.

The Loblolly Pine is commonly used for timber, phone poles, and paper, but is a high-terpene producing resin plant.

Turpentine

Many of the oleoresins from pine trees (and other trees listed below) have high levels of terpenes. Terpenes are a class of organic compounds (hydrocarbons) that a tree produces to repel pests; however, terpenes are produced and/or used in almost all living creature in the world. Some examples of natural products containing terpenes are steroids and beta-carotene. Once a terpene is altered, it is known as a terpenoid.

Turpentine is a fluid obtained by distilling high-terpene oleoresins. Collected oleoresins are placed into a steam distiller, and the turpentine is evaporated off and collected in a condenser. Turpentine can also be extracted via a process known as destructive distillation which occurs during pyrolysis (this is the process that occurs with the proper use of rocket stove technology). I can’t find a lot of information on obtaining turpentine through pyrolysis, but when I do, I will share it.

Turpentine can be used as a solvent (a substance that dissolves other substances) and to produce varnish. It can also be mixed with beeswax to make a high quaility furniture wax. Turpentine can be burned in oil lamps and can be mixed with ethanol to make “burning fluid”, an illuminant. Turpentine is mainly used today, once it has been processed, as synthetic pine oil. Pine oil is used for fragrance, flavoring, and in cleaning agents to give the “pine” odor.

Trees that have traditionally been primary sources of terpentine:

  • Aleppo Pine (Pinus halepensis)
  • Loblolly Pine (Pinus taeda)
  • Longleaf Pine (Pinus palustris)
  • Maritime Pine (Pinus pinaster)
  • Ponderosa Pin (Pinus ponderosa)
  • Scots Pine (Pinus sylvestris)
  • Slash Pine (Pinus elliottii)
  • Sumatra Pine (Pinus merkusii)
  • Balsam Fir (Abies balsamea) – produces Canada Balsam. Used as a glue for eyeglasses, a traditional medicine, and in soaps and perfumes.
  • Terebinth or Turpentine Tree (Pistacia terebinthus) – a very-long lived tree from the Mediterranean and Middle East.
  • Larch (Larix species) – produces Venetian Turpentine. Used in varnish, traditional medicine, and traditional chewing gum.
  • Red Spruce (Picea rubens) – produces Spruce Gum. Used as a traditional chewing gum.

 

Pine Rosin

Pine Rosin

Other Resin Products

Rosin (aka Colophony) – ROsin (not REsin) is the substance left over after turpentine is distilled from resin. Rosin is a solid and ranges in color from yellow to black. It is used by violinists and other string instrument musicians, in sealing wax, varnishes, medications, foods, and in electronic soldering.

Pine Tar – produced when heating Pine wood at high temperatures without catching fire (pyrolysis). Water and tar drip from the wood leaving charcoal behind. Used as a wood preservative and water sealant (boats, roofs, ropes, etc.) and in soaps and traditional human and veterinary medicines.

Pitch – Pine Tar is heated so that the water is evaporated. When the tar thickens, it is called pitch. Pitch was traditionally used for waterproofing seams and wooden containers (buckets, barrels, boats, etc.) and roofs. Some people consider Pine Tar and Pitch the same thing, others separate them based on consistency… Pine Tar being more liquid than Pitch.

 

Varnishing a hand-crafted wooden canoe.

Varnishing a hand-crafted wooden canoe.

Additional Definitions

Varnish – This is a protective “finish” or application for wood and other materials. Varnish is usually transparent or mostly transparent. It goes on wet and dries hard. It can have various levels of sheen (high gloss, glossy, semi-gloss, satin, etc.). Traditional varnishes contain an oil, a resin, and a solvent. The oils, also known as drying oils, harden after long exposure to oxygen. Examples of drying oils are linseed oil, poppy seed oil, tung oil, and walnut oil. Resins have been discussed at length above, and varnish resins include amber, copal, balsam, copaiba, elemi, mastic, rosin, and sandarac. The most common solvent, by far, is turpentine.

Lacquer – This is a type or method of varnishing, but is typically treated separately. Most varnishes undergo a chemical reaction that causes the varnish to harden. However, lacquers only undergo evaporation. If the solvent is reapplied to the finish (i.e. the lacquer), it will soften again. The resin that is traditionally used to make lacquer is lac (you can see where the name comes from!). Lac is the secretion from the lac insects of Asia. The dried secretion is refined and cleaned with a few different methods and then dries into shellac flakes. These flakes are dissolved in a solvent (lacquer thinners or alcohols) to make liquid shellac. Modern lacquer uses synthetics like polyurethanes, acrylics, or alkyds. Because these lacquers do not contain lac, they are not called shellacs, just lacquers. Another difference between modern varnishes and lacquers is that modern lacquers/shellacs are sprayed on while varnishes are brushed on.

 

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Photo References:

  • http://floridamemory.com/fpc/prints/pr12607.jpg – State Archives of Florida, Florida Memory, http://floridamemory.com/items/show/11013
  • http://archives.clayclerk.com/Photos/Exhibit-Turpentine-7.jpg
  • http://irwinvillega.files.wordpress.com/2012/04/trap-used-on-pine-tree-for-catching-sap-for-turpentine-distillation-irwin-county-georgia-arthur-rothstein-august-1935-library-of-congress-turpentine-picture-image-photo-copyright-brian-b.jpg
  • http://www.diamondgforestproducts.com/turpentine_catface.png
  • http://community.poppyswap.com/wp-content/uploads/2012/06/pineSap.jpg
  • http://cookingfromthefarm.files.wordpress.com/2013/03/img_1787.jpg
  • http://www.biolandes.com/production-plantes-aromatiques.php?id=11&lg=en
  • http://upload.wikimedia.org/wikipedia/commons/1/14/Frankincense_2005-12-31.jpg
  • http://upload.wikimedia.org/wikipedia/commons/b/b6/Amber2.jpg
  • http://diamondgforestproducts.net/wp-content/uploads/2014/03/rosin_spreadout1.jpg
  • http://upload.wikimedia.org/wikipedia/commons/6/6e/Loblolly_Pines_South_Mississippi.JPG
  • http://canoeguybc.files.wordpress.com/2012/10/apply-shellac.jpg

 

Additional References: