Resin has been used for thousands of years as glue, waterproofing, medicine, incense, embalming fluid, and decorative finish. Few natural materials have served as many purposes. Trees produce resin to defend against insects and seal wounds in their bark, but humans discovered early on that this sticky, aromatic substance could solve a remarkable range of practical problems.
Why Trees Make Resin in the First Place
Resin is part of a tree’s immune system. When bark is damaged by an insect boring into it or a branch snapping off, the tree pushes resin into the wound to seal the opening and kill or trap invaders. The sticky compounds in resin, primarily terpenes and phenolic chemicals, are toxic or repellent to many insects and fungi. Trees store these defensive compounds in specialized internal channels called resin ducts, ready to deploy when tissue is damaged.
Conifers like pines, spruces, and firs are especially prolific resin producers, which is why so many historical uses trace back to these species. But flowering trees also produce resins. Frankincense comes from Boswellia trees in the Horn of Africa and Arabian Peninsula. Myrrh comes from the related Commiphora genus in the same region. Pistacia trees around the Mediterranean produce mastic, one of the most valued resins in the ancient world.
Prehistoric Glue for Stone Tools
The oldest documented use of resin is as an adhesive. Neanderthals living in Europe between 55,000 and 40,000 years ago collected pine resin and used it to glue stone cutting edges onto handles made of wood or bone. Chemical analysis of stone flints from these sites confirmed pine resin on the surfaces, and in one case, the resin had been mixed with beeswax to adjust its properties. This wasn’t a casual discovery. These toolmakers traveled away from their caves specifically to harvest resin from pine forests, then processed it into a workable adhesive. It was, in effect, the first glue.
Embalming the Dead in Ancient Egypt
The ancient Egyptians incorporated tree resins into their mummification process. Resins from Pistacia trees, known commercially as mastic gum or chios turpentine, were mixed with fats and oils to create balms applied to the body and wrappings. The natural antimicrobial properties of these resins helped slow decomposition. Researchers analyzing a beef rib mummy from the tomb of Yuya and Tjuia (18th Dynasty, roughly 1386 to 1349 BC) found a balm with a high concentration of Pistacia resin, more elaborate than what was used on many human mummies of the same period. The Egyptians didn’t reserve these preservation techniques for people alone. They prepared food offerings for the dead with the same exotic ingredients.
Waterproofing Ships
For any civilization that built wooden boats, keeping water out of the seams between planks was a constant problem. Pine pitch, made by heating pine resin until it thickens into a dark, tarry substance, was the standard solution for millennia. Builders packed it into the gaps between planks to create a watertight seal, a process called caulking.
Analysis of the Hjortspring boat, a pre-Roman Iron Age vessel from Scandinavia, revealed that its caulking was a mixture of pine pitch and animal fat. Building a single boat of that size required up to 6 kilograms of pitch, more than one tree could produce in a year, which meant the builders needed access to substantial pine forests. This demand shaped where boats could be constructed and linked shipbuilding directly to timber resources. The age of wooden naval fleets ran on pine resin as surely as it ran on wind.
Religious Incense and a Global Trade
Frankincense and myrrh are aromatic resins that fueled one of the ancient world’s most lucrative trade networks for over 5,000 years. Frankincense burns with a fragrant, lingering smoke and became central to religious ritual across multiple cultures. The Old Testament describes its use in carefully measured mixtures for temple purification. Christians adopted incense in religious services about 1,700 years ago, and frankincense remains a staple in Roman Catholic, Coptic, and Orthodox Christian rites today, typically making up about two-thirds of the incense blend burned during services.
Because these resins grew in only one region, the small kingdoms of southern Arabia held a monopoly on supply and trade routes. The Queen of Sheba famously controlled portions of this commerce. At the peak of the ancient frankincense trade roughly 1,900 years ago, more than 3,000 tons per year were shipped across the Roman Empire. Myrrh, reserved for more elite uses, commanded twice the price of frankincense. Entire kingdoms rose and fell on the economics of these tree resins.
Traditional Medicine
Pine and spruce resins have a long history in folk medicine across Europe. People applied softened resin directly to wounds, burns, and boils as a protective covering, essentially a natural bandage with mild antiseptic properties. In Transylvania and other parts of Central Europe, fir resin was pressed into cavities to treat decayed teeth and was also used for cleaning teeth. Spruce resin was prepared as an ointment for skin diseases or heated so its vapors could be inhaled to treat coughs and colds.
These weren’t fringe remedies. Pine resin preparations appeared in the Hungarian Pharmacopoeia across eight editions spanning from 1871 to 2006, listed in formulations for adhesive plasters, inhalation oils, and turpentine preparations. The antiseptic and sticky qualities that help trees seal their own wounds turned out to work reasonably well on human skin too.
Wood Finishing and Shellac
Not all useful resins come from trees. Shellac is a resin secreted by the female lac bug, an insect native to the forests of India and Thailand. The bug deposits resin on tree branches as it moves along them, forming tunnel-like tubes that can be scraped off, processed, and dissolved in alcohol to create a smooth, protective coating.
Shellac replaced oil and wax as the dominant wood finish in the 19th century. For decades, it was the standard way to give furniture a glossy, durable surface. It held that position until nitrocellulose lacquer overtook it in the 1920s and 1930s. Shellac is still used today by woodworkers who prefer its warm tone and easy repairability. It also played an unexpected role in early technology: shellac was the material used to press phonograph records before vinyl took over.
Rosin for Musical Instruments
Rosin is a solid form of resin, typically from pine, that has been processed to remove liquid turpentine. String musicians have used it for centuries. Violinists, cellists, and double bassists rub a block of rosin across their bow hair before playing. The rosin creates friction between the horsehair of the bow and the strings, allowing the bow to grip and vibrate the string rather than sliding silently across it. Without rosin, a bow produces almost no sound at all.
Different formulations suit different playing conditions. Light rosin works better in warm temperatures and produces a smoother tone, while dark rosin grips the string harder and is designed for fuller, more powerful playing.
Amber: Resin Fossilized Over Millions of Years
When tree resin is buried in sediment and subjected to heat and pressure over millions of years, it polymerizes into amber. This fossilized resin has been prized as a gemstone since antiquity, valued for its warm golden color and the way it feels lighter than stone in your hand. But amber’s greatest scientific contribution is what it traps inside. Insects, plant fragments, feathers, and even small vertebrates preserved in amber retain extraordinary detail, giving researchers windows into ecosystems tens of millions of years old.
The richest amber deposits date to the Cretaceous period, during an interval of roughly 54 million years when coniferous forests produced resin on a massive scale. Researchers have named this the “Cretaceous Resinous Interval.” The combination of prolific resin-producing conifers, proximity to coastal and swampy environments where resin could be quickly buried, and warm Cretaceous climates created the conditions for amber deposits that are still being mined and studied today.
The Jump to Synthetic Resins
In 1907, chemist Leo Hendrik Baekeland created Bakelite, one of the first fully synthetic plastics, by reacting phenol with formaldehyde. His original goal was to find a synthetic replacement for shellac, which depended entirely on lac bugs harvested in Asia. Bakelite could be molded into shapes that held up under heat and electrical current, making it ideal for telephone housings, electrical insulators, and radio casings. It was the material that launched the plastics age.
Today, synthetic resins are everywhere: in epoxy adhesives, fiberglass composites, 3D printing materials, and the coatings on everything from floors to circuit boards. They inherited the core properties that made natural resins useful for millennia, the ability to start as a liquid and harden into a tough, protective solid, but with chemistry that can be tuned precisely for each application.