Balsa Tree

Ochroma pyramidale



Malvaceae (Mallow Family)



Trunk and Bark

Balsa is considered a pioneer species growing in previously uncolonized/disturbed areas or secondary forest. It is fast growing and reaches heights of 30 meters. It has smooth, grayish bark, which is sparsely branched; however, the weakly palmately (looks like the palm of a human hand), lobed (3-5) leaves can be quite dense (Mora, Mendez, & Gomez, 1999). The leaves are long-stemmed and broad and are approximately 30cm. The base of the leaf is heart-shaped. The leaves are green with a gray-green underside and are covered with reddish epidermal hairs, which give them a sandpapery feel (Zuchowski, 2007).The trunk is very cylindrical and usually very straight, although it can be gently curved and, is very rarely buttressed (New World Encyclopedia, 2008). It also has a sticky, viscous sap.The flowers begin from large buds whose golden calyx is formed from five fused sepals, which cover the developing petals. Once the calyx begins to peel back 4-12 cm long, bell-shaped, erect, solitary flowers are revealed which contain five whitish, overlapping, folded petals and five fleshy sepals (Mora, Mendez, & Gomez, 1999). The flowers have a scent similar to a raw pumpkin and resemble ice cream cones. The fruits grow rapidly from the old flower calyxes, which appear as long green rods. When mature, the fruit splits open lengthwise revealing seeds (3-4 mm) surrounded by a tan fluff (New World Encyclopedia, 2008). This resembles a short, fuzzy paint roller (Zuchowski, 2007).

Look closely to see the unique leaf shape


Mostly flowers in the dry season, but can also flower late in the rainy season. The fruit is seen in the dry season and later. The flowers are nocturnal (open at night) as the stigma, or the male organ which receives pollen from the anther so it can begin the process of seed fertilization, is closed during the day. Therefore, nocturnal animals such as bats or diurnal animals such as coati pollinate the flowers (Zuchowski, 2007). Coatis have been observed by Mora et al. gently sticking their noses into the flower of the Balsa most likely in search of nectar or insects. As a result the flower was unharmed and the coatis walk away with pollen grains attached to their faces, which suggests possible pollination; thus, creating a symbiotic relationship. However, Balsa is mainly a bat pollinated species. During the day a variety of birds eat the flowers, including parrots and macaws (New World Encyclopedia, 2008).

The seeds of the Balsa (contained in the fruit) are covered in a fluffy kapok coat, which helps it disperse itself by floating through the air and landing on land or water
(Zuchowski, 2007).


Ochroma species are found from southern Mexico to Bolivia (Mora, Mendez, & Gomez, 1999). They are native to the tropical America, but are now cultivated in other parts of the world. In Costa Rica they are found in moist, wet lowlands as well as near rivers in dry regions. They will grow on slopes and are found from sea level to approximately 1,200 m. They often grow in sunny, open areas where there has been a fire or disturbance (Zuchowski, 2007).


The seeds fluffy kapok coat make it great for filling pillows and furniture. Balsa is valued for its soft, lightweight wood (softest commercial hardwood). It is ideal for rafts, boxes, insulation, and model airplanes. It was actually a component of airplanes during World War II and was used to make Stim-U-Dents. Balsa is commercially grown in South America. Native people of tropical America have used Balsa to make boats, which makes sense as balsa in Spanish means raft. The bark fibers can also be made into twine (Zuchowski, 2007).

There are also some medicinal uses of Balsa. The root or bark can be prepared and used as a diuretic. A flower decoction (mashing and boiling to extract oils) is used to treat colds and coughs. A decoction of flower and bark is can be used as an emetic or vomit inducer. The sap from young balsa trees can be used as an external emollient. Some claim Balsa seeds have an edible oil (Zuchowski, 2007).

Works Cited

Mora, J.M., Mendez, V.V., & Gomez, L.D. (1999). White-nosed coati Nasua narica as a potential pollinator of Ochroma pyramidale. Rev. Biol. Trop., 47(4), 719-721.

New World Encyclopedia, . (2008, April 2). Balsa. Retrieved from

Zuchowski, W. (2007). Tropical plants of Costa Rica. Ithaca, New York: Cornell University Press, Sage House.