Ochroma pyramidale, Corkwood, West Indian balsa, Balsa, Bois flot

Ochroma pyramidale, commonly known as the balsa tree or Corkwood, is a species of flowering plant in the mallow family, Malvaceae, and is the sole member of the genus Ochroma. The plant is widely distributed in tropical America; throughout the West Indies, and from southern Mexico, through Central America, and into Venezuela, Colombia, Brazil, Ecuador, Peru, and Bolivia. It is planted in many tropical countries, including tropical Africa (e.g. Cameroon and Zimbabwe) and South Africa. It has locally become naturalized. The tree is the source of balsa wood, very lightweight material with many uses. The name balsa originates from the Spanish word for “raft.”

Corkwood, West Indian balsa, Balsa, Bois flot, Corkwood, Rowntree, Balsa wood, Balsa tree, Down tree, Cork tree, Ajaka, Baranda, Basilic des Moines, Basilic Sacre, Bidai, Brinda, Bryanda, Gaggera, Hsiang tsai, Kala Tulsi, Kamangi and Kaphrao are some of the well-known common names of the tree. Balsa wood timber is considered the lightest known commercial timber. It has a very wide range of applications but is probably best known as a material for making model planes etc. It has been extensively planted in many tropical areas, though 90% of all commercial supplies are grown in Ecuador. The tree is an excellent pioneer species for restoring native woodland and establishing woodland gardens. It is occasionally planted as an ornamental or to provide shade.

Corkwood Facts

Plant Description

Balsa tree or Corkwood is a deciduous or evergreen, fast-growing, short-lived, medium-sized tree that normally grows about 60 to 90 ft. tall and 2.5 to 4 ft. in diameter. On the best sites, it may reach a height of 80 ft. and a diameter of 2.5 ft. in 5 years. It has been known to grow even faster on very rich soils. Bole is straight, usually short, cylindrical, up to 100(–180) cm in diameter, with short buttresses in older trees. The Bark surface is smooth, grey-white mottled. Crown is spreading and large. Branchlets are stellate and hairy. The plant is found growing in moist, lowland, limestone forests, margins of lakes or in disturbed areas and is rare in the older forest. The tree is mostly found on fertile, bottom-land soils along the sides of streams. It is classified as hardwood despite the wood itself is very soft. It is the softest commercial hardwood and is widely used because it is lightweight.

Leaves

Leaves are simple, spirally arranged towards the ends of the twigs. Lamina is broadly cordate, 10-26 cm long and 14-30 cm wide, thin coriaceous ± entire or angularly lobed. Apex is obtuse to acuminate, base rounded to cordate, persistently densely stellate-tomentose below, glabrescent above, midrib and main veins slightly raised to sulcate above, strongly prominent below; venation 5-7-palmate at the base, midvein with 4-6 lateral veins. The petiole is terete, 2-4 mm diameter and 12-20 cm long, moderately stellate-tomentose even on mature leaves, ± dilated apically; stipules ± deltoid, to 10 mm long, densely tomentose and caduceus.

Flowers

Flowers are solitary, lateral or axillary, on a stout, fleshy pedicel 7 mm diameter and 10 cm long.  The calyx is tubular to funnel-shaped, 7 cm long, apically with 5 dilated lobes 1.5-2 cm long, appearing deeply carinate externally in dried material, externally stellate-tomentose, internally wooly, decurrent with pedicel, and subtended by 3 caducous bracteoles that leave prominent scars.  Petals 5, contorted in the bud, orange-yellow, clavate, 13 cm long and 5 cm wide, externally stellate-tomentose, glabrescent basally, internally glabrous. Stamens are connate into a glabrous tube 11 cm long, the distal half being slightly dilated and densely covered with sessile long wavy anthers.  The ovary is sessile, glabrous, conical, 8 cm high, 5-locular. Style is 15 cm long with an apical twisted cylindrical stigmatic mass 3 cm long and 8 mm wide.

Fruit

Fertile flowers are followed by cylindrical, ellipsoid, slightly curved capsule, longitudinally sulcate, loculicidal, 15 cm long and 8 mm wide, ribbed, 5-valved, dehiscent, densely woolly hairy inside.  Seeds are black, pear-shaped, 4–5 mm long, and 1.5 mm wide, embedded in a mass of brown woolly hairs.

Different Facts of Balsa tree or Corkwood

• The woolly fiber contained in the seedpods has occasionally been used like kapok as a stuffing material in pillows and mattresses.
• The fiber obtained from the bark has been used to make ropes.
• The grain is straight; texture coarse and even; the luster silky.
• The wood is very soft and weak, but with good strength to weight ratio, and that from old trees tends to be brittle.
• It is non-durable and prone to attack by Anobium and Lyctus borers, termites, and longhorn beetles.
• The wood is very easy to work with hand and machine tools, but sharp tools are needed to prevent crumbling.
• The pulp can be easily bleached without loss of strength, making it suitable for printing and writing papers.
• The extremely lightweight wood is used for floats, buoys, lifejackets and life-belts, surfboards, aircraft construction, ship and boat building, lightweight boxes, toys, model making, laboratory mounting boards, core stock in sandwich construction, surgical splints, packaging of fragile articles and as insulation for temperature, vibration, sound and formerly also for electricity.
• Slightly heavier wood is suitable for matches, Popsicle sticks, and toothpicks, and for the production of pulp and paper.
• Trees can commence flowering and producing viable seeds when 3 – 4 years old.
• The tree is sometimes planted as an ornamental or to provide shade.
• Indigenous Peoples carve elegant sculptures, build houses, boats, and trays to prepare food, make toys such as stilts.
• The Balsa plant has been used to build vessels for river transportation, which allowed Indigenous Peoples (according to some studies) to navigate great distances.
• Lightwood of the Balsa is used mainly to make surfboards and scale airplanes for model airplanes.

Precautions

• Corkwood tree is unsafe when taken by mouth. It can cause death.
• Corkwood tree can cause many side effects including dry mouth, decreased perspiration, dilation of pupils, blurred vision, red, dry skin, increased body temperature, increased heart rate, difficulty urinating, hallucinations, spasms, acute? psychosis, convulsions, and coma.
• Overdose poisoning symptoms include sleepiness followed by restlessness, hallucinations, delirium and manic episodes followed by exhaustion and sleep.
• It’s unsafe for anyone, including pregnant or breastfeeding women, to take corkwood trees.

References