Abstract: Pinus canariensis (Canary Island Pine or Pitch Pine) forms natural forests on the islands of Tenerife and La Palma. The heartwood has an extraordinarily high resin content, and this paper provides an anatomical description of the wood as well as an interpretation of the factors relating to this resinification. Pinus canariensis possesses many subsidiary parenchyma cells surrounding the axial resin canals. Similarly, the percentage of rays is high, which means there are many parenchyma cells capable of accumulating large amounts of starch, which in turn can be used for the synthesis of the pitch extractives, primarily terpenoids and polyphenols. The presence of subsidiary parenchyma cells and the high percentage of rays are a major contributor to the heartwood of Pinus canariensis being rich in extractives.