Modern society consumes enormous amounts of plastics. Albeit bringing convenience to our daily life, these plastics pose great harm to the environment. In fact, way before the rise of the modern chemical industry, people have been using resin extracted from trees “natural plastic” for making objects for daily use. Industrially made plastics are cheap. “Natural plastics” are gems – they may have an aroma or are crystal clear depending on which trees they originate from.
Resin is the sticky fluid coming from trees. The primary ingredient is terpene, an organic compound which is highly volatile, insoluble in water and aromatic. In contact with air, the fluid may harden into a solid as the terpene. Besides deriving from the trees, some resin is produced by insects, such as Indian Lac Insect (Laccifer lacca). The female lac insect secretes a protective covering for its nymphs, which becomes resin on the trees.
Not all trees produce resin. Conifers are the most productive of them. It is yet unknown why trees produce resin. The common view is that resin is produced when the plant is wounded. Constituents of the resin can ward off or even kill insects, or prevent fungi infection to protect the wound.
The common “plastic”
There is a wide variety of resins, each made up of complex structures, hence allowing different applications in our daily life - particularly before the advent of the modern chemical industry. Mixing resins with paints produces emulsion paints. Resins can also be used to make insulating materials or adhesive agents. A special example is Balsam Fir (Abies balsamea), the resin of which can be made into Canada balsam, which is a transparent fluid having a similar coefficient of refraction to glass. It is therefore used like a glue for use with glass.
The precious “plastic”
In contrast to artificial plastic, natural resin can be very precious in nature. The most renowned is frankincense, the resin from the plant Boswellia spp. of the Family Burseraceae. Frankincense is widely used as incense in religious ceremonies in holy temples. Frankincense was also featured in the Bible as a gift to Jesus, when the Three Wise Men from the East visited Jesus at his birth in Bethlehem. In former days, frankincense was widely traded in Egypt and Europe. Heads of states would even send commissioners out to procure the precious resin.
Apart from the diverse use of “fresh” resin, fossil resin is even more of a gem. Amber, the crystallised yellowish-brown jewel, is the fossil of ancient resin. It has been collected as embellishments since the Neolithic era. In addition, amber sometimes contains insects, small animals or other plant materials in their original state, making it an ideal specimen to study ancient biology.