Huaiji Pine Resin

Huaiji Pine Resin

　　A colorless, transparent, viscous liquid found in pine trees, formed by the dissolution of solid resin acids (70%–80%) in terpenes (20%–30%). Steam distillation of pine resin yields turpentine and rosin.

　　The sugars produced by photosynthesis in pine needles undergo complex biochemical changes to form pine resin within the thin-walled cells of the wood. This resin seeps into resin canals through the walls of resin-secreting cells. Resin canals are a unique structure in pine trees, forming three independent systems in the xylem, needles, and primary cortex. The xylem resin canals include both longitudinal and transverse types, which interconnect within the wood to create a resin canal system. When harvesting pine resin, simply making an incision in the outer xylem layer of the trunk allows the resin to flow out through the resin canal system.

　　Its sap is white. Pine resin is secreted by trees of the Pinus genus. When first exuded from the trunk, it is colorless and transparent, with a turpentine content of over 30%. Upon exposure to air, the turpentine gradually evaporates, and external moisture infiltrates, causing some of the resin acids to crystallize and precipitate. As a result, the resin gradually turns into a honey-like semi-fluid substance. Pine resin mainly consists of resin acids and terpenes, along with small amounts of impurities and water.

　　The content of resin acids and terpenes varies depending on the tree species, origin, resin-tapping method, and storage period. The typical composition of Masson pine resin is: 72–75% rosin, 16–20% turpentine, 4–6% water, and 0.05–0.3% impurities.