As a fast-growing grass, bamboo can serve as a renewable feedstock for a range of building material uses worldwide. With a tensile strength close to steel and a compressive strength twice that of concrete, bamboo is used for structural columns and beams, foundation, flooring, roofing and walls (Chung and Yu 2002; Hegde and Sitharam 2015; Lv, Ding and Liu 2019; Yadav and Mathur 2021).
Progress in engineered bamboo shows mechanical performance comparable to that of heavy timber (Sun, He and Li 2020). Bamboo poles can be adopted for a range of scaffolding, shear wall and complex structures. Bamboo structures are key candidates for use in seismic (earthquake) and flood zones, towards expanding the use of bamboo in climate change resilience planning.
The bamboo plant has a rapid growth rate and can reach maturity in under five years; as such, bamboo forests can play a key role in carbon sequestration (Liese and Köhl 2015). Currently, bamboo forests occupy an estimated area of 36 million hectares globally, or around 3.2 per cent of the global forest area (Lobovikov et al. 2007; Phimmachanh, Ying and Beckline 2015). Globally, an estimated 30 per cent of bamboo is grown in forest plantations (Beena and Seethalakshmi 2011).
Bamboo is considered to be a frontrunner for driving afforestation practices to mitigate climate change. Global studies of the annual carbon sequestration capacities of bamboo range from 5 to 24 tons of carbon per hectare; on the lower end, this is 1.46 times the sequestration capacity of forests and 1.33 times that of tropical rainforests (Yen and Lee 2011; Nath, Lal and Das 2015; Yuen, Fung and Ziegler 2017). Unlike the carbon sequestration losses associated with timber logging, selective bamboo harvesting may be less ecologically damaging to forests, and productive species can yield between 150-296 tons per hectare of forest plantation land (Seethalakshmi, Jijeesh and Balagopalan 2009).
However, the global availability of land for scaling up bamboo plantations is decreasing, in direct competition with other land uses, particularly for housing and agriculture (Seethalakshmi, Jijeesh and Balagopalan 2009).
Figure 4.4 Carbon emissions and storage for laminated bamboo versus other building materials
Laminated bamboo products generate comparable emissions as steel but offer carbon storage potential
Most of the carbon emissions from bamboo products are generated during the production stage, which relies on a range of toxic treatment chemicals to improve the material’s resistance to mold and corrosion. The use of synthetic treatment chemicals, glues and high-temperature air for drying can lead to the tripling of CO2 emissions relative to timber-based products (Xu, Xu et al. 2022).
Per unit of volume, studies demonstrate that laminated bamboo products can generate carbon emissions comparable to those of steel (see Figure 4.4). However, unlike steel and cement, bamboo also offers carbon storage potential, at levels slightly higher than for some other harvested wood products. Overall, bamboo’s carbon emissions potential is around 63 per cent, whereas its carbon sequestration potential is around 37 per cent (Xu, Xu et al. 2022).
Due to the high carbon emissions and ecological impacts of chemicals used in the treatment of bamboo, progress is needed towards the development of low-carbon, eco-friendly alternatives. Current approaches include water leaching as well as processes that rely on botanical preservatives and the use of effluents from paper milling production (Kaur et al. 2016); such processes occur largely in small-scale, experimental operations today. Key ways to reduce emissions from bamboo manufacturing include re-using bamboo products at their end-of-life and providing on-site renewable energy (Vogtländer, van der Velden and van der Lugt 2014).
Incentivise commercial-scale bamboo industries to use bio-based alternative chemicals for treatment.
Manufacturers must gradually phase out the use of toxic, fossil fuel-based chemicals and glues.
Research and investment are needed in the development of non-toxic, bio-based treatment chemicals and glues for laminated bamboo products.
Key engineered bamboo standards provide guidance on the testing and standardisation of engineered bamboo performance for structural design (ISO 2004a; ISO 2004b; ISO 2022a).
Highly productive and sustainable plantation management practices can be accelerated, with 63 per cent of resources privately owned, unlike timber where 80 per cent are government-owned (Lobovikov et al. 2007).
Large and growing demand for bamboo in countries like China provides an opportunity for sustainable management outcomes, much as the rise in demand for timber products helped drive afforestation and carbon sequestration practices in Europe and North America (Lou et al. 2010).
Transitioning to renewable energy sources for manufacturing is critical given the energy requirements of bamboo manufacturing, particularly during the treatment and production stages.
Bamboo cultivation depends on seeds from flowering plants (Seethalakshmi, Jijeesh and Balagopalan 2009; Singh et al. 2013), but the shortage of planting stock is a key barrier to expanding bamboo’s carbon storage potential.
Novel cultivation methods include offset planting, culm and branch cutting, and rhizome planting.