Resin canal

Resin canals or resin ducts are elongated, tube-shaped intercellular spaces surrounded by epithelial cells which secrete resin into the canal. These canals are orientated longitudinally and radially in between fusiform rays.^[1] They are usually found in late wood, or denser wood grown later in the season.^[2] Resin is antiseptic and aromatic and prevents the development of fungi and deters insects.

Resin canals seen as white dots in pine tree viewed under a microscope

Axial resin canal (Picea abies)

Pinus; leaf (3 needle type) Resin Canal

Types

• Normal resin canals exist naturally in the wood of the genera Picea, Larix, Pinus, Pseudotsuga and Shorea.
• Traumatic, irregularly-shaped resin canals may be formed in wounded trees that do not have normal resin canals. Wounding occurs by fire, freezing or mechanical damage.^[2]

Characteristics

Resin canal characteristics (such as number, size and density) in pine species can determine its resistance to pests. In one study, biologists were able to categorize 84% of lodgepole pine, and 92% of limber pines, as being either susceptible or resistant to bark beetles based only on their resin canals and growth rate over 20 years.^[3] In another study, scientists found ponderosa pine trees that survived drought and bark beetle attacks had resin ducts that were >10% larger in diameter, >25% denser (resin canals per mm²), and composed >50% more area of per ring.^[4]