Fighting climate change with bamboo

Bamboos are a diverse group of evergreen perennial flowering plants, the largest of the grass family. Bamboo is versatile and has notable economic and cultural significance in South Asia, Southeast Asia and East Asia. The parts of bamboo, primarily the stems, are used for building materials, as a food source, and as a raw product. Bamboo stems, like wood, are a natural composite material with a high strength-to-weight ratio that is useful for structures.

Presently, bamboo occupies an area of 36 million hectares worldwide, equivalent to 3.2% of the total forest area in the world. In Sri Lanka, there are more than a dozen species growing in Sri Lanka, of which some are endemic and some are introduced. They are found on both private and government lands. According to a survey in 1991, the two widely used bamboo species in the country, Ochlandra stridulate, located in state forests, and Bambusa vulgaris, mainly found on private lands. Read more about the varieties of bamboo in Sri Lanka here Archived.

The University of Moratuwa, Department of Architecture, with the support of Thuru, a social enterprise in Sri Lanka, initiated a bamboo building design project for first-year undergraduates to promote bamboo as a building material.  The Climate Fact Checks team spoke to lecturer Dr Nadeeka Jayaweera from the university to learn more about this project and its capacity to fight climate change.

Bamboo as a sustainable building material

Bamboo is used as a green construction material popular in East Asian countries. Due to its rapid growth and minimum contribution to climate change, it is widely used in tropical countries as a sustainable building resource. “Although Sri Lanka has not had a tradition in constructing buildings using bamboo, it is important to explore the option with the current economic crisis and prize hike in regular construction material”, stated Dr Nadeeka as she spoke about the inspiration behind starting the building design project. This was included in a course module for first-year architecture students at the University of Moratuwa to explore the designs of different building structures using Bamboo. “Bamboo is recognised as one of the most sustainable construction materials, but not explored enough in Sri Lanka as the native bamboo species cannot be utilised for the purpose,” said Dr Nadeeka. She added that “Introduced bamboo plants currently grow in Sri Lanka, especially the species Dendrocalamus giganteus (E: Giant bamboo, S: Yoda Una) and Dendrocalamus asper (s: Una) which are used in constructions also used in Bali.”

She also mentioned that treating bamboo can last up to 40-50 years, and these facilities exist in Sri Lanka, in places like the Industrial Development Board (IDB). Additionally, these treatment methods can be carried out chemically using preservatives or non-chemically via techniques like culm curing, leaching in water, smoking and whitewashing.  Read more about Bamboo Harvesting and Preservation here.

Special features of bamboo

Bamboos include some of the fastest-growing plants in the world due to a unique rhizome-dependent system. Certain species of bamboo can grow 91 cm (36 inches) within a day at a rate of almost 40 mm (1.5 inches) an hour. This rapid growth and tolerance for marginal land make bamboo a good candidate for afforestation, carbon sequestration and climate change mitigation. Bamboo possesses a vast advantageous usage scheme which is environmentally friendly; concerning trees (wood) gathered within 10–30 years, bamboo can be collected within 3–5 years.

Bamboo is also strong and durable, even better when treated right. It is known as the “Green steel” due to the strength it holds. In addition, bamboo, as in other grasses, have stems that are usually hollow which makes it lightweight and flexible. Bamboo fibre is also considered more hygienic due to its natural anti-bacterial properties. Hence, no external chemicals are necessary.

How to use bamboo to fight climate change?

Bamboo has a rapid growth rate and is considered an efficient carbon sink. Due to this, it takes only three years to establish mature groves. As a result, bamboo is an effective carbon dioxide absorber, not only above-ground carbon (AGC) but also below-ground carbon (BGC) in roots and rhizomes. To a lesser extent, it absorbs soil organic carbon (SOC) too. Notably, growing out of a tangle of underground stems, bamboo can help reforest landscapes denuded by development or natural disasters, binding topsoil to prevent erosion.

It is estimated that bamboo absorbs 2x more carbon dioxide than trees and also generates a vast amount of oxygen, totalling up to more than 30% compared to other plants and trees.

Can bamboo replace fossil fuels?

While 60 – 70% of bamboo culm on maturity can be utilised to create value-added products such as handcrafts, furniture, etc., the residue becomes a valuable source of energy. Bamboo has several desirable fuel characteristics, such as low ash content and low surface moisture. The high heat value (HHV) of bamboo is higher than most identified fuel wood and scores close to the commonly used rubber wood.  Through pyrolysis, up to 50% of the carbon can be transferred from bamboo tissue to biochar (organic fertiliser), with the remaining 50% used to produce energy and fuels. Bamboo charcoal (BC) is one kind of manufactured biochar, a plentiful residual byproduct of the bamboo processing industry.

In collaboration with the Institution of Engineers of Sri Lanka (IESL), UNIDO recently unveiled a Forum on Bamboo for Energy and Industrial Sustainability. The Forum is organised under the “Bamboo Processing Sri Lanka” project was launched by the United Nations Industrial Development Organization (UNIDO) and funded by Global Environment Facility (GEF). The project aims to develop a bamboo supply chain and product industry in Sri Lanka. “Evergreen Sri Lanka” Forum hopes to build awareness and transfer the necessary knowledge on bamboo as a biomass energy source and to promote bamboo as a substitute for hardwood in an eco-friendly manner.

Plan book is a global company working with climate-conscious businesses, farmers, land stewards, and biochar producers. They partnered with Aitken Spence, Elpitiya Plantations, on a biochar project after the ban on fertilizer. Ever since, Plan book has been teaching large tea, cinnamon, and rubber plantations in Sri Lanka to produce biochar to boost their compost production. From designing and fabricating kilns to finding the perfect blends of organic liquid compost, the local team is ready to scale their solution throughout the country.

Role of bamboo in an ecosystem

Despite all these benefits, there is one significant downside to bamboo production. As bamboo picks up demand, production needs to keep up. Due to increasing popularity, large areas of land are being cleared to be planted with bamboo. This can lead to wildlife displacement and decreased ecosystem biodiversity. When bamboo is grown as a crop, it’s also often done as a monoculture. This means only bamboo is planted, and all other varieties are removed. Monocultures create problems for fungi, bacteria, insects and other smaller animals that rely on a diverse ecosystem for nutrition and habitat. In China, pandas almost went extinct due to the over-exploitation of bamboo, a staple for them.

Can Bamboo create a form of Livelihood in Sri Lanka?

Sri Lanka’s bamboo resource supports the household economy as they are the raw material used for the cottage handicraft industry, housing and construction purposes. Although the resource is not as abundant as in other Southeast Asian countries, bamboo has been utilised in many ways since ancient times. Bamboo resources meet subsistence needs and provide a source of cash income among rural families. Information obtained on the dependency of two villages on bamboo shows that the average number of visits to gather bamboo and the number of culms extracted per year vary. A survey done by Forest Department indicated that 79% of the people who harvest bamboo from state forests use the materials for themselves to manufacture crafts with household importance like baskets, winnowing fans etc.

Future of Bamboo in Sri Lanka

Sri Lanka has a potential future where bamboo is utilized to its best advantage. SRINBAR, or Lanka Network for Bamboo and Rattan, is a Non-Governmental Organization that allows people from different professions to interact and come up with various uses for bamboo in the country.