Hau-2

hau-2

Hawaiians remove the entire "bark" form the stems. This can be used directly to make a crude rope. Alternatively, the Fibers can be isolated from the Inner Bark to produce a finer cord.

Hau cordage (ili hau) was not very strong and did not tolerate salt water very well. However, it was very abundant and was probably used for many tasks, especially those which which did not require great strength or durability (Abbott, 1992).

Hau fibers are part of the Inner Bark (Secondary Phloem). They exist as bundles or bands of thick-walled cells that alternate with thin-walled conducting cells. The latter are involved in sugar transport. The fibers protect the conducting cells from physical trauma and allow the Phloem to function for a long time.

High magnification view of Hau Fibers using Polarized Light: Note the thick cell walls. The small dark areas at the center of each fiber contains the living matter of these cells. The rest is Cell Wall. The red color indicates the presence of Lignin

Fibers appear bright with polarized light and they usually stain red for the presence of Lignin with Phloroglucinol. Lignin is more prevalent in the older fibers which are the ones nearest to the surface.

New Secondary Phloem is produced by meristematic tissue that lies between the Secondary Xylem & Phloem. This meristem is called the Vascular Cambium. It renews the Secondary Phloem that is lost from the plant. Consequently, plants can be used more than once if some of the "bark" remains continuous above and below a wound.

Cross-sections of Hau stem stained with Phloroglucinol and viewed with Polarized Light: The useful fibers are found in the Secondary Phloem a.k.a. Inner Bark. They are bright because they have thick walls and their red/orange color signifies the presence of Lignin in their cell walls.

Section from the Inner Bark (a.k.a. Secondary Phloem) of Hau, Stained with Phloroglucinol and viewed with Polarized Light: The bands of Fibers protect the thin-walled Conducting Cells of the Phloem.