Different types of fibers in hemp stem

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Hemp stems have two types of fibers:

  1. Some long fibers that are rich in cellulose and pectin, present in the stem bark, and known as bast fibers.
  2. And other woody short fibers that are found in the stem core, which are richer in lignin and xylans, which are commonly known as hurds (Petit et al. 2019 ; Figure 1)..

Figure 1. Short and long fibers from the hemp stem. According to the industrial application, it will be more advisable to use one or the other type of fiber.

Bast fibers can likewise be divided in two types:

  1. The outermost layer of the stem, called long primary bast fibers, which are thicker, longer and richer in cellulose,
  2. and the long secondary bast fibers that are in direct contact with hurd, which are thinner, shorter, and have more lignin than the primary ones. This means, they more closely resemble the hurd with which they are in contact.

Long secondary bast fibers become more abundant as the plant increase its maturity degree, due to the fact that long fibers lignify progressively as the plant grows older.

The process of decortication separates both types of fibers- bast and hurd- which significantly widens and optimizes the trading possibilities of the hemp stem.





References:

Petit J, Gulisano A, Dechesne A, Trindade LM. Phenotypic Variation of Cell Wall Composition and Stem Morphology in Hemp (Cannabis sativa L.): Optimization of Methods. Front Plant Sci. 2019 Jul 25;10:959. doi: 10.3389/fpls.2019.00959. PMID: 31402925; PMCID: PMC6671528.