Resin canals or resin ducts are elongated, tube-shaped intercellular spaces surrounded by

epithelial cells Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

which secrete

resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

into the canal. These canals are orientated longitudinally and radially in between

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

rays. They are usually found in late wood, or denser wood grown later in the season.

Resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

is antiseptic and aromatic and prevents the development of fungi and deters insects.

Types

* Normal resin canals exist naturally in the wood of the genera ''Picea'', ''Larix'', ''Pinus'', ''Pseudotsuga'' and ''

Shorea Fruit of a ''Shorea'' species ''Shorea'' is a genus of about 47 species of mainly rainforest trees in the family Dipterocarpaceae. The timber of trees of the genus is sold under the common names lauan, luan, lawaan, meranti, seraya, balau, bang ...

''. * 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.

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 ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpin ...

, and 92% of limber pines, as being either susceptible or resistant to

bark beetle A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although th ...

s based only on their resin canals and growth rate over 20 years. In another study, scientists found

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine, is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is t ...

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.Kane, J.M. & Kolb, T.E. Oecologia (2010) 164: 601. https://doi.org/10.1007/s00442-010-1683-4

Types

Characteristics

References

Further reading