Balsa
Encyclopedia
Ochroma pyramidale, commonly known as the balsa tree (also O. lagopus), is a species of flowering plant
in the mallow
family, Malvaceae
. It is a large, fast-growing tree
that can grow up to 30 m (98.4 ft) tall. It is the source of balsa wood, a very lightweight material with many uses. Balsa trees are native from southern Brazil
and Bolivia
north to southern Mexico
.
n countries. It is a pioneer plant, which establishes itself in clearings in forests, either man-made or where trees have fallen, or in abandoned agricultural fields. It grows extremely rapidly, up to 90 ft (27.4 m) in 10–15 years. The speed of growth accounts for the lightness of the wood; balsa wood has a lower density than cork. Trees frequently do not live beyond 30 to 40 years.
Flowers are produced from the third year onwards, typically at the end of the rainy season when few other trees are in flower. The large flowers open in the late afternoon and remain open overnight. Each may contain a pool of nectar up to 1 in (2.5 cm) deep. Daytime pollinators include capuchin monkey
s. However most pollination occurs at night. It was once thought that the main pollinators were bats; however recent evidence suggests that two nocturnal arboreal mammals, the kinkajou
and the olingo
, may be the primary pollinators.
supplies 95 percent or more of commercial balsa. In recent years, about 60 percent of the balsa has been plantation
grown in densely packed patches of around 1000 trees per hectare (compared to about two to three per hectare in nature). It is evergreen
, or dry-season deciduous
if the dry season is long, with large (30–50 cm (11.8–19.7 in)) weakly palmately
lobed leaves. Trees are classified as hardwood because of the shape of their leaves, so balsa, with its large, broad leaves is classified as hardwood
despite being very soft. It is the softest commercial hardwood. The trees are harvested after six to 10 years of growth. The name balsa comes from the Spanish word for "peanut".
is very soft and light, with a coarse, open grain
. The density
of dry balsa wood
ranges from 40–340 kg/m³ (2.5–21 lb/ft³), with a typical density of about 160 kg/m³ (10 lb/ft³).
The light weight of the wood derives from the fact that the tree has large cells that contain water. After the water is driven off in an extended drying process (kiln dried for two weeks), the large surface area of the resulting holes gives strength. Unlike dry rotted wood, the surface is made of the usual strong cellulose
/lignin
mix.
As it is low-density but high in strength, balsa is a very popular material to use when making light, stiff structures in model bridge tests, model tree houses, and for the construction of model aircraft
, as well as full-sized light wooden aeroplanes
, most famously the World War II
de Havilland Mosquito
.
Balsa is used to make wooden crankbaits
for fishing.
Balsa wood is often used as a core material in composites
; for example, the blades of many wind turbine
s are made partially of balsa. In table tennis
paddles, a balsa layer is typically sandwiched between two pieces of thin plywood
. Balsa wood is also used in laminate
s with glass-reinforced plastic
(fiberglass) for making high-quality balsa surfboard
s and the decks
and topsides of many types of boat
s, especially pleasure craft under 30 m (98.4 ft) in length. Starting with the 5th generation Chevrolet Corvette, the floor pan of the Corvette was composed of balsa sandwiched between two sheets of carbon fiber reinforced plastic.
Norwegian scientist/adventurer Thor Heyerdahl
, convinced that early contact between the peoples of South America
and Polynesia
was possible, built the raft Kon Tiki from balsa logs, and upon it he and his crew sailed the Pacific Ocean
from Peru
to the Polynesian Tuamotu Archipelago
in 1947. Balsa wood is also a popular wood type used in the art of whittling
.
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
in the mallow
Malva
Malva is a genus of about 25–30 species of herbaceous annual, biennial, and perennial plants in the family Malvaceae , one of several closely related genera in the family to bear the common English name mallow. The genus is widespread throughout the temperate, subtropical and tropical regions of...
family, Malvaceae
Malvaceae
Malvaceae, or the mallow family, is a family of flowering plants containing over 200 genera with close to 2,300 species. Judd & al. Well known members of this family include okra, jute and cacao...
. It is a large, fast-growing tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
that can grow up to 30 m (98.4 ft) tall. It is the source of balsa wood, a very lightweight material with many uses. Balsa trees are native from southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
north to southern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Biology
A member of the mallow family, O. pyramidale is native to southern Brazil north to southern Mexico, but is now found in many Latin AmericaLatin America
Latin America is a region of the Americas where Romance languages – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...
n countries. It is a pioneer plant, which establishes itself in clearings in forests, either man-made or where trees have fallen, or in abandoned agricultural fields. It grows extremely rapidly, up to 90 ft (27.4 m) in 10–15 years. The speed of growth accounts for the lightness of the wood; balsa wood has a lower density than cork. Trees frequently do not live beyond 30 to 40 years.
Flowers are produced from the third year onwards, typically at the end of the rainy season when few other trees are in flower. The large flowers open in the late afternoon and remain open overnight. Each may contain a pool of nectar up to 1 in (2.5 cm) deep. Daytime pollinators include capuchin monkey
Capuchin monkey
The capuchins are New World monkeys of the genus Cebus. The range of capuchin monkeys includes Central America and South America as far south as northern Argentina...
s. However most pollination occurs at night. It was once thought that the main pollinators were bats; however recent evidence suggests that two nocturnal arboreal mammals, the kinkajou
Kinkajou
The kinkajou , also known as the honey bear , is a rainforest mammal of the family Procyonidae related to olingos, coatis, raccoons, and the ringtail and cacomistle. It is the only member of the genus Potos. Kinkajous may be mistaken for ferrets or monkeys, but are not closely related...
and the olingo
Olingo
Olingos are small procyonids that comprise the genus Bassaricyon, native to the rainforests of Central and South America from Nicaragua to Peru. They are arboreal and nocturnal, and live at elevations from sea level to 2,000 m...
, may be the primary pollinators.
Cultivation
EcuadorEcuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
supplies 95 percent or more of commercial balsa. In recent years, about 60 percent of the balsa has been plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
grown in densely packed patches of around 1000 trees per hectare (compared to about two to three per hectare in nature). It is evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
, or dry-season deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
if the dry season is long, with large (30–50 cm (11.8–19.7 in)) weakly palmately
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
lobed leaves. Trees are classified as hardwood because of the shape of their leaves, so balsa, with its large, broad leaves is classified as hardwood
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
despite being very soft. It is the softest commercial hardwood. The trees are harvested after six to 10 years of growth. The name balsa comes from the Spanish word for "peanut".
Uses
Balsa lumberLumber
Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....
is very soft and light, with a coarse, open grain
Wood grain
In speaking of wood the term grain refers to the alternating regions of relatively darker and lighter wood resulting from the differing growth parameters occurring in different seasons . The term is used in several ways. Perhaps most important is that in woodworking techniques...
. The density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of dry balsa wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
ranges from 40–340 kg/m³ (2.5–21 lb/ft³), with a typical density of about 160 kg/m³ (10 lb/ft³).
The light weight of the wood derives from the fact that the tree has large cells that contain water. After the water is driven off in an extended drying process (kiln dried for two weeks), the large surface area of the resulting holes gives strength. Unlike dry rotted wood, the surface is made of the usual strong cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
/lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
mix.
As it is low-density but high in strength, balsa is a very popular material to use when making light, stiff structures in model bridge tests, model tree houses, and for the construction of model aircraft
Model aircraft
Model aircraft are flying or non-flying models of existing or imaginary aircraft using a variety of materials including plastic, diecast metal, polystyrene, balsa wood, foam and fibreglass...
, as well as full-sized light wooden aeroplanes
Fixed-wing aircraft
A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...
, most famously the World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
de Havilland Mosquito
De Havilland Mosquito
The de Havilland DH.98 Mosquito was a British multi-role combat aircraft that served during the Second World War and the postwar era. It was known affectionately as the "Mossie" to its crews and was also nicknamed "The Wooden Wonder"...
.
Balsa is used to make wooden crankbaits
Plug (fishing)
Plugs are a popular type of hard-bodied fishing lure. They are widely known by a number of other names depending on the country and region. Such names include crankbait, wobbler, minnow, shallow-diver and deep-diver...
for fishing.
Balsa wood is often used as a core material in composites
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
; for example, the blades of many wind turbine
Wind turbine
A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. If the mechanical energy is used to produce electricity, the device may be called a wind generator or wind charger. If the mechanical energy is used to drive machinery, such as for grinding grain or...
s are made partially of balsa. In table tennis
Table tennis
Table tennis, also known as ping-pong, is a sport in which two or four players hit a lightweight, hollow ball back and forth using table tennis rackets. The game takes place on a hard table divided by a net...
paddles, a balsa layer is typically sandwiched between two pieces of thin plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...
. Balsa wood is also used in laminate
Laminate
A laminate is a material that can be constructed by uniting two or more layers of material together. The process of creating a laminate is lamination, which in common parlance refers to the placing of something between layers of plastic and gluing them with heat and/or pressure, usually with an...
s with glass-reinforced plastic
Glass-reinforced plastic
Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....
(fiberglass) for making high-quality balsa surfboard
Surfboard
A surfboard is an elongated platform used in the sport of surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding a breaking wave...
s and the decks
Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...
and topsides of many types of boat
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...
s, especially pleasure craft under 30 m (98.4 ft) in length. Starting with the 5th generation Chevrolet Corvette, the floor pan of the Corvette was composed of balsa sandwiched between two sheets of carbon fiber reinforced plastic.
Norwegian scientist/adventurer Thor Heyerdahl
Thor Heyerdahl
Thor Heyerdahl was a Norwegian ethnographer and adventurer with a background in zoology and geography. He became notable for his Kon-Tiki expedition, in which he sailed by raft from South America to the Tuamotu Islands...
, convinced that early contact between the peoples of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...
was possible, built the raft Kon Tiki from balsa logs, and upon it he and his crew sailed the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
from Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
to the Polynesian Tuamotu Archipelago
Tuamotus
The Tuamotus or the Tuamotu Archipelago are a chain of islands and atolls in French Polynesia. They form the largest chain of atolls in the world, spanning an area of the Pacific Ocean roughly the size of Western Europe...
in 1947. Balsa wood is also a popular wood type used in the art of whittling
Whittling
Whittling is the art of carving shapes typically out of raw wood or bone with a knife.Whittling is typically performed with a light, small-bladed knife, usually a pocket knife. Specialised whittling knives are available as well...
.