Why banana palm?
The world demand for fibre increases constantly (with wood products around 3,300 million cubic meter for 2009). Trees, both from plantations and forests, are currently the primary source for this fibre which is facing important sustainability, environmental and regulatory issues.
Through Papyrus’ detailed research for an environmental substitute to wood-based fibre, the trunk of the banana palm was identified as an ideal source of fibre.
A renewable fibre source
Renewable sources of fibre are plenty and can be divided into two main categories:
Primary fibre crops
Primary fibre crops are those crops that are grown for their fibre such as cotton, tree plantations, jute, flax, hemp and kenef
Secondary fibre crops
Secondary fibre crops such as plantain/banana, sugar cane, cereals, palm oil and tobacco are not grown for their fibre but rather for their fruit, sap, seed, oil and leaves respectively
The economic and environmental costs associated with secondary fibre are much lower than those for primary fibre. In the search for a suitable renewable secondary fibre crop, the seasonal nature of some crops becomes a considerable factor in selecting fibre alternatives. For example, the use of cereal straw in paper and or panel production is hampered by the fact that all cereals are harvested at the end of a narrow season, creating problems and costs in storage and dictating seasonal production.
Crops such as banana, plantain, rubber and palm oil are harvested throughout the year, resulting in a linear and more uniform availability and therefore constant production.
Papyrus identified the banana & plantain as a sustainable, renewable and abundant secondary fibre crop available all year round with over 10 million hectares (and on average 1,500 plants per hectare) in more than 160 countries (see diagram 1).
Diagram 1: Banana & plantain growing regions
Depending on plant type and location, a plant from the banana family (Genus Musa) will produce a new trunk every 6 to 12 months, unlike timber sources that have a long growth cycle and can only be harvested once.
In addition, after the fruit is harvested, the trunk is cut and left to rot emitting a huge amount of methane and carbon dioxide. Growth occurs year round and harvesting of fruit occurs daily, allowing the Banana Tree Trunks (BTT) to be harvested with the Papyrus technology continually, removing the need for stocks of raw material to be accumulated during the off season as is the case when using any other fibre crops.
And as there is currently no economically viable use for the banana trunk, it is an ideal choice of raw material for the production of paper and other timber products like cardboard, veneer, chipboard and fibreboard.
The banana plant
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. In popular culture and commerce, ‘banana’ usually refers to soft, sweet ‘dessert’ bananas. By contrast, Musa cultivars with firmer, starchier fruit are called ‘plantains’.
The banana plant (see diagram 2 below), often erroneously referred to as a ‘tree’, is a giant perennial herbaceous monocotyledon; in fact, a large herb. The fruit, although it develops from an inferior ovary, is also technically a berry.
The succulent, juicy stem is made of leafy sheaths that grow from a fleshy bulb with the core growing up through the centre.
Suckers spring up around the main plant forming a clump or ‘stool’. The eldest sucker replaces the main plant when it fruits and dies and this process of succession continues indefinitely. In a plantation, the banana plants are in essence natural clones.
Diagram 2: The banana plant
Diagram 3: The banana trunk – cross section view
The trunk structure enables two different products depending upon which layer (see diagram 3) the product is manufactured from. The coarse, outer layer of the trunk produces a heavy board-type product, while the inner layer allows the manufacture of a finer, more decorative product.
The structure of the banana tree trunk is such that individual fibres, which are extremely long and strong, extend from the base of the stem through the entire trunk. This creates a product that is stronger and more durable than traditional forest wood products. Preserving the natural structure of the fibre is the key to producing a high quality end product, which are naturally fire retardant, water repellent and UV resistant.
In addition, the fibre derived from BTT is unusually consistent by comparison with forestry-derived products because all banana plants within a plantation are in essence naturally cloned.