Tree resin is a sticky substance produced by many types of trees, particularly conifers like pine and fir. It serves as a protective mechanism, helping to seal wounds and deter insects and pathogens. The resin can harden when exposed to air, forming a solid material that can be harvested for various uses. Resin has been utilized by humans for thousands of years. It is often used to make products like turpentine, which is a solvent, and rosin, used in music for string instruments. Additionally, some resins are valued for their aromatic properties and are used in incense and perfumes.