Bast fibres (sclerenchyma cells) are found in the inner bark (or skin) of the plant stem. Their role is to provide stiffness and strength to the growing plant. Nettle, flax, hemp and jute are examples of fibre producing plants.
Breaking, first step after retting in the processes to remove the fibres from the woody stalks.
Decortication which is a mechanical peeling operation to separate the fibres from the stalk.
Hackling is a combing process used to separate the long fibres from the short fibres and to remove the remaining woody material.
Pectin One of the substances that binds the individual fibres cells together to form long strands or groups, and also to bind the fibres to the other stem material..
Phloem, or inner bark (or skin) of a plant. This is the plant tissue that transports nutrients.
Processing of bast fibres: Retting, Breaking, Scutching Hackling, Combing.
Scutching: second step, after retting, to remove the fibres from the woody stalks, which is done by beating with blunt wooden or metal blades either by hand or mechanically.
Retting is a controlled ‘rotting’ to remove the gummy (pectinous) substances which glue the bast fibres together, and this can be achieved with different methods:
- Chemical retting involves immersion of the dried plants in a tank with a solution of chemicals, such as sodium hydroxide, sodium carbonate, high pH agents, pectinolytic enzymes or mineral acids. The fibers are loosened in a few hours, but close control is required to prevent deterioration and damage to the fibres. Chemical retting is more expensive and does not produce the superior quality fibre obtained from the biological retting process.
- Dew retting is a more sustainable process where the stalks are left out in the field for 6 weeks, and are acted upon by the dew, sun and fungi. Dew retting tends to yield a dark-colored fiber. However, it is far less labor intensive and less expensive than water retting. It is commonly used in regions of low water supply. Currently dew retting is the dominant and most desirable method from a sustainability perspective
- Water retting involves leaving the stalks in tanks or ponds of water (or in a running river), and are acted upon by bacteria, rotting the stalk which separates the fibres from the woody core. It takes 2–4 weeks for dam retting. In tanks with warm water, the time is reduced to a few days. Water retting gives a more uniform quality product. In stream retting the plants are immersed in slow moving streams for a longer time and the quality of the product is high. The nutrients from the decaying stalks means that this method is highly polluting to the water source.
Urticaceae: Here is a summary of the genera in the Urticaceae family:
http://www.theplantlist.org/browse/A/Urticaceae/ The stinging nettle belongs to Urtica, ramie belongs to Boehmeria and the Nepalese nettle belongs to Girardinia, so they all have equal status as nettles. There are other genera in the family that have fibre plants and Touchardia is one of them, though I notice it’s missing from the list.
All information, bar the last link, is replicated from the UAL’s site for sustainable fibres and fabrics. Please refer to this site for more information. Reviewed by Gillian Edom.