Natural resins are exuded from trees, especially pines and firs. Resin forms as a result of injury to the bark from wind, fire, lightning, or other cause.  

Resins are soluble in various organic liquids but not in water. They are typically transparent or translucent and are yellowish to brown in colour. Natural resins have properties similar to man-made ones, such as strength, durability, and chemical resistance. Natural resins can be easily molded and cast into a wide range of shapes and sizes.

The most common source material for natural resins is polylactic acid, which comes from corn. However, there are some downsides to this material choice as corn requires the use of a petroleum-based fertilizer to grow, which partially runs into waterways and thus pollutes marine life.

A better alternative to corn is sugarcane, which does not need as much land and produces fewer emissions during processing.

EcoPoxy resin is another plant-based material with characteristics similar to that of an epoxy resin. EcoPoxy products are up to 54% bio based, non-toxic, and emit no harmful fumes.

Some natural resins are biodegradable or compostable.