More About Bast Fiber Plants

About the Fiber

There are many plants that are used to produce fiber for industrial use both modern and historically, and the fibers come from a variety of parts: The leaves, the seeds, the fruit, from grass, from wood, and from the stem (Figure 1). The fibers produced from the stem of the plants are called bast fibers.

Figure 1: Types of Plant Fibers (Jan Salski 2009)

Bast is a specific type of fiber that is produced in the layer of the plant between it’s core and the skin, if the plants that produced bast fibers were trees it would be a section of the inner bark. The most common cultivated bast crops in North America are flax and hemp. These were historically used to make linen; or, in the case of hemp, rope.

When the stem of a bast plant is examined microscopically it is easy to determine three layers, the first is a very thin layer of epidermis, next is the layer of fiber surrounded by the phloem of the plant, and the last is the xylem or core (Figure 2). The epidermis is the skin of the plant, the phloem carries organic nutrients (like sugar) made during photosynthesis to the plant, and the core and xylem carries water and other nutrients from the soil to the plant. In trees the phloem is the bark and they xylem is the wood. In bast plants the fiber that we use is in the phloem layer - unlike wood. For both hemp and flax it is this bast fiber that we are trying to get from the plant and all the processing steps out lined on the previous page are meant to remove the other tissues surrounding the fibers.

Figure 2: Dissection of a hemp stem for bast fiber

Current uses of plant fibers are much more varied then historical uses. Historically bast fiber was usually used for cloth, rope, and paper. Modern uses have expanded the number of products that it can be used for to include composites (house mouldings, and car parts); OSB (oriented strand board), Bio-fuels, and for Resins (glues).

Because of the dual nature of flax and hemp the seeds were often used to produce oil; especially for large inland populations (such as China and Russia) that did not have easy access to fish or whale oils typically used as lamp oil. Hemp can also be used medicinally, however the varieties of the plants that produce high levels of drugs tend to produce inferior fiber, and the fiber varieties tend to have low levels of the drug present in the plant.

In Canada the plants produced for fiber have such a low level of the psychoactive component in them that the amount you would have to smoke would make you ill before it made you high.

A short comparison of Hemp History to Flax History