The term bark loosely refers to the outer covering of the stem and branches. Technically, it includes all the tissues from outside the cambium to the outermost layers of a woody stem. The bark serves as a protective tissue. It acts as a conduit transporting food to the other parts of the tree. About 8% of the total volume of a tree in bark.
Bark consists of an outermost corky layer called epidermis, a layer of manufactured
food-conducting tissues called phloem, a zone between these two layers known as cortex. In several species, a layer of fibrous strips called “bast fiber” forms an innerbark. Oils, resins, tannins, waxes and phenolic substances may be present in the bark.
Cork, fiber, tannins, gums, resins, latex materials can all be derived from barks. The most
common yet the oldest and lowest grade uus of unprocessed bark is for fuel.
Following are some of the other uses of barks:
1. Bark rich in tannin – a substance used in:
a) tanning leather, preparation of binders and wood adhesives, drying fishnets, ropes, soils and clothing.
c) rust prevention
d) ink manufacture
The barks of kamatchili, some mangrove species like ‘bakawan-babae’, busaing, langaral,
pototan and ceriops tagal are the main sources of tanning materials.
2. Bast fiber – another portion of the bark found just under the outer bark – strong, tough and durable and can be made into cloth, turinas, bowstrings, fish lines, sacks. Paper from
mulberry and salago have fine bast fibers which can be made into high grade quality paper such as bank notes and checks. Those of kalulot and other similar species are made into lady’s handbags, wallets and placemats. Bast fibers of anonang, malabuho, and sinaligan yield silky and lustrous interlaced filaments which are pliable and strong. These can be used in the manufacture of elegant hats, handbags, placemats and wallets.
Anabo, anonang, ‘kulantingan’, ‘malubago’ and sinaligan have tough and durable bast fibers with good folding endurance and bending sterngth. They can also be made into cordage and wild bag trap.
3. Barks can also be potential sources of saponins – a lathe-producing substance which can be used in the formulation of shampoo.