Element Analysis of Bamboo Construction-Related Resource

Huang, Zujian

doi:10.1007/978-3-030-73535-7_2

Zujian Huang²

Part of the book series: Green Energy and Technology ((GREEN))

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Abstract

Sustainable bamboo construction requires systematic and scientific integration and allocation of involved resources to achieve the optimization of a comprehensive value. The resources mentioned include not only nature but also social and human aspects. A clear analysis of resource elements is a prerequisite for clarifying the decisive variables related to the sustainability of bamboo construction activities. For this, the chapter summarizes the status quo of the bamboo forest resource, bamboo industrial utilization, and processing technology, as well as the economic, social, and environmental impacts of the bamboo industry, which lays the foundation for the development of sustainable solutions.

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2.1 Bamboo Forest Resource

2.1.1 General Distribution

Bamboo forests provide initial raw materials for bamboo utilization. Generally, the bamboo forests across the world are mainly distributed in three major bamboo-growing regions: the Asia-Pacific Bamboo Area, the American Bamboo Area, and the African Bamboo Area. The “Asia-Pacific Bamboo Area” mentioned herein is different from the geographic term “Asia-Pacific Region”. The “Asia-Pacific Region” is the shortened form of the Asia and the Pacific Rim, containing the entire Pacific Rim in a broad sense or referring to the Western Pacific Region in a narrow sense, mainly including the East and Southeast Asian countries; while the “Asia-Pacific Bamboo Area” contains the middle and low latitudes of East Asia, Southeast Asia, South Asia, and the Western Pacific Islands, with the boundaries in the four directions being approximately New Zealand at 42°S, central Sakhalin at 51°N, the Pacific Islands, and the Southwestern Indian Ocean, respectively.

According to the investigation conducted by the International Center for Bamboo and Rattan (ICBR) and the International Bamboo and Rattan Organization (INBAR), the area of the Asian bamboo forests accounts for more than 70% of the global total which is 37 million hectares as published by INBAR, and the number of the Asian bamboo species accounts for about 70% of the world’s total which is 1,642 as identified by now. Among them, the commercial bamboo species include Thyrsostachys siamensis, Dendrocalamus latiflorus, Bambusa oldhamii, Phyllostachys violascens, Phyllostachys glauca, Phyllostachys reticulata, Dendrocalamus barbatus, Bambusa balcooa, Bambusa chungii, Bambusa glaucophylla, Dendrocalamus asper, etc., accounting for more than 70% of the global commercial bamboo species. The bamboo industry in East Asia represented by China is developed, that in Southeast Asia represented by Vietnam and Malaysia is developing rapidly, and that in South Asia represented by India is underdeveloped although with the largest bamboo forest area [1].

Most of the identified bamboo species in the world grow in the tropical and sub-tropical regions and a few in the temperate regions. In the Asia-Pacific Bamboo Area, the dominant bamboo genera for industrial utilization include Bambusa, Cephalostachyum, Dendrocalamus, Gigantochloa, Melocanna, Ochlandra, Phyllostachys, and Thyrsostachys. Except for Phyllostachys edulis which is a running bamboo, the rest are mostly clumping ones. However, in terms of area, the clumping bamboos and running bamboos account for about 60% and 40%, respectively, in the Asia-Pacific Bamboo Area [1].

2.1.2 Main Bamboo Producing Countries

The bamboo-producing countries in the Asia-Pacific Bamboo Area are: Bangladesh, Cambodia, China, India, Indonesia, Japan, Malaysia, Myanmar, the Philippines, South Korea, Sri Lanka, Thailand, and Vietnam, most of which are INBAR members (Fig. 2.1; Table 2.1).

Table 2.1 Bamboo resources of main bamboo-producing countries in the Asia-Pacific Bamboo Area

Full size table

2.1.2.1 East Asia

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China

China ranks first in bamboo resources, stock volume, and production volume in the world. The total area of bamboo forests is 6,411,600 hectares, among which the areas of natural and artificially planted bamboo forests are 3,903,800 hectares and 2,507,800 hectares, respectively, accounting for about 60% and 40%, respectively. The bamboo forests are mainly distributed in 16 provinces, municipalities, and autonomous regions south of 35°N. From a utilization perspective, the area of bamboo forests for timber use accounts for 36.32%, that for shoot use 5.56%, that for both timber and shoot use 24.11%, that for paper pulp use 13.98%, and that for ecological and public benefit 18.67% [2]. China has 870 bamboo species, accounting for more than half of the total 1,642 species in the world.

The most researched and utilized bamboo species are Phyllostachys edulis, Phyllostachys violascens, Phyllostachys glauca, Phyllostachys makinoi, Phyllostachys sulphurea var. viridis, Phyllostachys bissetti, Dendrocalamus latiflorus, Bambusa oldhamii, Bambusa emeiensis, Chimonobambusa quarangularis, etc. Among them, Phyllostachys edulis forests are the main part of China’s bamboo forests, covering an area of 4,677,800 hectares, accounting for 72.96% of the total area, with a stock volume of 14,125 million bamboos, mainly distributed in 13 provinces, municipalities, and autonomous regions across the country. Among the Phyllostachys edulis forests, those under intensive management witness continuous area increase from 6% in the 1980s to nearly 40% in 2018, and significant quality improvement with the number of bamboos with DBH of 7–11 cm accounting for 61.92% [1].

China has a rich bamboo product system, covering nearly 10,000 types of 10 categories, including traditional bamboo products, artificial bamboo boards, papermaking bamboo pulp, bamboo fiber products, bamboo charcoal, bamboo vinegar, bamboo leaf extract, and processed bamboo shoot products. In 2017, China produced 2.72 billion bamboo culms, 5,720,500 tons of bamboo-based panels, 119,478,300 square meters of bamboo flooring, 858,000 tons of bamboo shoots, and 1.65 million tons of bamboo pulp. In 2018, China’s bamboo industry had a total output value of about RMB 280 billion (i.e., about USD 39,333 million), with more than 8 million employees.

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Japan

Japan has 141,300 hectares of bamboo forests (in 2010) and about 100,000 hectares of artificially planted Phyllostachys edulis forests, which are distributed all over the country, with 60% concentrated in Kyushu. There are more than 230 bamboo species under 13 genera, among which Phyllostachys edulis, Phyllostachys reticulate, and Phyllostachys sulphurea are the most planted ones [3].

Japan’s bamboo industry enjoyed its heyday from the 1960s to the 1970s and suffered population decline, population aging, and labor cost increase in the bamboo producing areas after the 1980s. 97% of the bamboo forests are privately owned and intensively managed, and the bamboo industry mostly focuses on family workshops or small factories. Japan has an annual output of 200,000–300,000 tons of bamboos, with bamboo products mainly centering on traditional handicrafts and about 100,000 employees working in the bamboo industry. It also produces bamboo articles for daily use, bamboo building and courtyard materials such as walls, indoor and outdoor decorative materials, railings, fences, etc., as well as bamboo flooring, bamboo plastic, bamboo pulp paper, bamboo fiber, bamboo charcoal fiber, bamboo charcoal, bamboo vinegar, bamboo antibacterial agent, bamboo shoot, and so on. It used to be the major bamboo shoot producer in the world but is overtaken by China, the major bamboo shoot processing base now, as a result of processing technology transfer to China in the mid-1980s.

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South Korea

South Korea has 22,100 hectares of bamboo forests (in 2016) [4] falling into 19 species of five genera, with main bamboo species for commercial use including Phyllostachys reticulate, Phyllostachys nigra var. henonis, Phyllostachys edulis, Phyllostachys nigra, Pseudosasa japonica, Sasa borealis, Sasa chiisanensis, Pleioblastus simonii, among others. At present, its bamboo industry nationwide is facing some common problems such as low salary for employees, insufficient input in equipment, out-of-date product design and processing technology, etc. and is being impacted by imported bamboo products.

2.1.3 South Asia

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Bangladesh

In Bangladesh, the area of the bamboo forests is 490,000 hectares, the bamboos fall into 33 species under nine genera, and the important commercial bamboo species include Melocanna humilis, Bambusa vulgaris, Bambusa balcooa, Bambusa tulda, Bambusa polymorpha, Schizostachyum dullooa, Thyrsostachys oliveri, Dendrocalamus hamiltonii, and Melocalamus compactiflorus. About 55% of the country’s bamboo forests are owned by villagers and provide about 80% of the country’s bamboo output. The bamboo industry has created job opportunities and made a significant contribution to Bangladesh, with the bamboos mainly used in the building industry to make railings, ladders, mats, pipes, and industrial and fishing tools.

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Bhutan

Bhutan’s bamboo resources are mainly concentrated in the central and southern regions, with 33 species belonging to 15 genera. From ancient times to the present, its bamboos have been used for house building, handicrafts, food, and tools, and are considered to have huge growth potential in the building industry.

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India

India is rich in bamboo resources but lacks recognized specific data on the area of bamboo forests. FAO announced in the Global Forest Resources Assessment 2010 that the bamboo forests in India covers 5.48 million hectares, but due to different statistical sources, the latest report says that the bamboo forests reach 16 million hectares, including 430,000 hectares of pure bamboo forests, 3.06 million hectares of mixed dense forests, 10.21 million hectares of scattered sparse forests, 820,000 hectares of cluster sparse forests, and 1.48 million hectares of other bamboo forests. The country has natural bamboo forests distributed nationwide, where the Northeast states and West Bengal account for more than half of the country’s total bamboo resources. There are 125 native bamboo species and 11 exotic bamboo species under 23 genera, among which Arundinaria, Bambusa, Chimonobambusa, Dendrocalamus, Dinochloa, Gigantochloa, etc. are dominant bamboo genera.

India boasts a long bamboo processing and utilization history, with bamboos mainly used for building, farm tools, furniture, food, bamboo pulp papermaking, handicrafts, etc. In India, the proportion of bamboo pulp to the total papermaking raw materials is as high as 45–60%, with the largest output of bamboo pulp papermaking in the world.

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Nepal

Nepal has 60,000 hectares of bamboo forests, including natural bamboo forests accounting for 60%, and 53 bamboo species under 12 genera, with main bamboo species including Arundinaria, Bambusa arundinacea, Bambusa balcooa, Bambusa nepalensis, Bambusa tulda, Bambusa vulgaris, Bambusa almaii, Cephalostachyum latifolium, Dendrocalamus hamiltonii, Dendrocalamus hookeri, Dendrocalamus strictus, Drepanostachyum falcatum, Himalayacalamus brevinodus, Himalayacalamus cupreus, Himalayacalamus porcatus, Melocanna humilis, Phyllostachys nigra, Thammocalamus spathiflorus, Yushania maling, etc. Nepal produces about 3 million bamboo culms per year, of which about 2.5 million ones are consumed domestically and 500,000 ones are exported. The bamboos are mainly used for building, flooring, artificial boards, handicrafts, food, and furniture manufacturing.

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Sri Lanka

In Sri Lanka, there is a total of 742,000 hectares of bamboo forests (according to FAO’s report in 2010) and 19 bamboo species including 10 native ones, such as Arundinaria densifolia, Arundinaria debilis, Arundinaria scandens, Arundinaria floribunda, Arundinaria walkerianam, Bambusa arundinacea, Davidsea attenuate, Dendrocalamus strictus, and Ochlandra stridula. The bamboo industry is dominated by traditional processing and utilization, mainly for building, flooring, fences, handicrafts, food, etc.

2.1.3.1 Southeast Asia

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Cambodia

Cambodia suffers a continuous decline of bamboo forest area, from 380,000 hectares in 1970 to 130,000 hectares in 2014. It mainly has four bamboo genera, specifically including Arundinaria falcata, Arundinaria pusilla, Bambusa arundinacea, Dendrocalamus asper, Bambusa flexuosa, Bambusa burmanica, Bambusa procera, Dendrocalamus membranaceus, Bambusa multiplex, Bambusa blumeana, Bambusa vulgaris, Gigantochloa albociliata, and so on. Cambodia’s bamboo industry is small in scale and dominated by traditional processing, with the bamboos used to make bamboo mats, bamboo furniture, fishing gear, etc., as well as building materials, handicrafts, and so on.

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East Timor

The main bamboo species identified in East Timor are Dendrocalamus asper, Schizostachyum brachycladum, Gigantochloa atter, Gigantochloa verticillata, Bambusa glaucoscens, among others. To promote the development of the bamboo industry, East Timor has established the bamboo research institute to conduct research in the fields of bamboo boards, bamboo furniture, bamboo handicrafts, etc., and strengthened the training of bamboo farmers to enhance the enthusiasm for developing bamboo resources.

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Indonesia

Indonesia is home to 2.1 million hectares of bamboo forests, of which 1.4 million hectares are gardens and farms and 700,000 hectares are wild lands. It has 160 bamboo species under 25 genera, of which 88 bamboo species are native. The bamboo species with important economic value include Bambusa blumeana, Bambusa vulgaris, Bambusa maculate, Dendrocalamus asper, Gigantochloa apus, Gigantochloa atter, Gigantochloa atroviolacea, Gigantochloa hasskarliana, Gigantochloa hirtinoda, Gigantochloa kuring, Gigantochloa luteostriata, Gigantochloa verticillata, Gigantochloa robusta, Gigantochloa serik, Gigantochloa tomentosa, Neololeba atra, Neololeba hirsute, Nastuselatus sp., Racemobambos raynaldii, Schizostachyum aequiramosum, Schizostachyum atrocingulare, Schizostachyum bamban, Schizostachyum brachycladum, Schizostachyum castaneum, Schizostachyum cuspidatum, Schizostachyum glaucocladum, Schizostachyum irraten, Schizostachyum longispiculatum, Schizostachyum mampouw, Schizostachyum zollingeri, among others. Indonesia uses its bamboos widely for house building, bridges, fishing gear, musical instruments, bamboo shoots, etc. Moreover, it promotes the development of the bamboo industry by expanding the area of artificially planted bamboo forests, developing bamboo-related eco-tourism, encouraging green bamboo building technology and bamboo biomass energy technology, and the like.

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Laos

Laos has 2.24 million hectares of bamboo forests classified into 86 species of 15 genera, mainly including Phyllostachys reticulata, Indosasa sp. 1, Fargesia sp. 1, Gigantochloa albociliata, Cephalostachyum pergracile, Thyrsostachys siamensis, Dendrocalamus membranaceus, Bambusa blumeana, Dendrocalamus hamiltonii, Dendrocalamus sinicus, Thyrsocalamus liang, and others. Laos mainly produces traditional bamboo products. In recent years, it has actively produced and exported bamboo raw materials, bamboo shoots, and bamboo furniture.

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Malaysia

Malaysia enjoys a wide distribution of bamboo forests covering more than 5 million hectares. It has 70 bamboo species of 10 genera, with most species distributed in Malay Peninsula, Negeri Sabah, and Negeri Sarawak. The main commercial bamboo species include Bambusa blumeana, Bambusa vulgaris, Bambusa heterostachya, Dendrocalamus asper, Gigantochloa levis, Gigantochloa ligulata, Gigantochloa scortechini, Gigantochloa wrayi, Schizostachyum brachycladum, Schizostachyum grande, Schizostachyum zollingeri, and so on.

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Myanmar

In Myanmar, there is a total of 859,000 hectares of bamboo forests (according to FAO’s report in 2010) falling into 102 bamboo species under 21 genera. The bamboo species with higher economic value are Bambusa arundinacea, Bambusa longispiculata, Bambusa polymorpha, Cephalostachyum pergracile, Dendrocalamus brandisii, Dendrocalamus giganteus, Dendrocalamus hamiltonii, Dendrocalamus longispathus, Dendrocalamus membranaceus, Dendrocalamus strictus, Dinochloa maclellandii, Gigantochloa rostrata, Melocanna humilis, and Thyrsostachys siamensis. Myanmar mainly uses its bamboos for houses, bridges, handicrafts, furniture, and food production. From 2014 to 2015, Myanmar produced about 2 billion bamboo culms, of which about 912 million were used by rural communities. In recent years, it has started to focus on the production and export of high value-added products, such as bamboo flooring, bamboo mats, bamboo furniture, bamboo charcoal, and bamboo crafts.

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Thailand

In Thailand, the total area of bamboo forests is 260,000 hectares (according to FAO’s report in 2010) and there are 72 bamboo species under 17 genera, mainly including Dendrocalamus, Bambusa, Thyrsostachys, Cephalostachyum, Gigantochloa, etc. Thailand mainly produces and exports raw bamboos, artificial bamboo boards, bamboo shoots, bamboo furniture, and the like.

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The Philippines

In the Philippines, the area of the natural bamboo forests is 188,000 hectares (according to FAO’s report in 2010) and that of the artificially planted bamboo forests will reach 256,000 hectares in 2022 as planned. There are 62 bamboo species, including 21 native or endemic ones. Among them, those with higher economic value are Bambusa blumeana, Bambusa vulgaris, Dendrocalamus asper, Gigantochloa atter, Gigantochloa levis, and Schizostachyum lumampao. The Philippines’ bamboos are mainly used for house building, furniture, handicrafts, and food production.

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Vietnam

Vietnam has 1.4 million hectares of bamboo forests, accounting for 10% of the country’s land area. Among them, natural bamboo forests, bamboo-wood mixed forests, and artificially planted bamboo forests account for 245,000 hectares, 1.10 million hectares, and 122,000 hectares, respectively [5].

From the perspective of domestic and foreign market demand, among 216 bamboo species under 20 genera, Vietnam boasts 10 bamboo species with potential commercial value, namely Dendrocalamus barbatus, Bambusa longissima, Phyllostachys pubescens, Dendrocalamus spp., Bambusa spp., Schizostachyum spp., Arundinaria spp., Indosasa spp., Bambusa procera, Thyrsostachys siamensis, and Maclurochloa sp., among which Lung (Bambusa longissima sp. nov) and Luong (Dendrocalamus barbatus) are the most common bamboo species in Thanh Hoa and Nghe An provinces, providing the main raw materials for Nghe An Hoa Binh and other traditional bamboo processing areas (such as Hanoi and Thai Binh) to produce handicrafts, furniture, and building materials. Vietnam’s bamboos are mainly used to make handicrafts, electric poles, houseware, and building boards, as well as bamboo charcoal to a certain extent.

2.1.4 International Trade

According to UN Comtrade’s HS (Harmonized System) code (HS 2017), the international trade volume of bamboo stalks (i.e., bamboo raw materials, with HS code 140110) was 203577.2/146865.9 t (import/export) and that of industrial bamboo products (with HS code 441210 and 441873) was 206816.5/116153.7 t (import/export) in 2018. However, in fact, the data may be underestimated, because most bamboo product transactions occurred at home, and bamboo products are often labeled as timber instead in export trade. There are no separate HS codes for different varieties of bamboo boards (Fig. 2.2; Table 2.2).

Table 2.2 International trade volume of bamboo products

Full size table

Within the scope of the “Asia-Pacific Bamboo Area”, the East Asia region generally accounts for most of the relevant trade. For the raw bamboo products, countries in East Asia, South Asia, and Southeast Asia all export raw bamboos, and the importers are mainly countries in East Asia and South Asia. For the industrial bamboo products, China accounts for the vast majority of export volume, while some countries in Southeast Asia, such as Vietnam, also have export records. Importers of industrial bamboo products are mainly countries in Southeast Asia and Oceania (Fig. 2.3; Annex Table 2.5).

2.2 Industrial Utilization and Processing Technology of Bamboo

2.2.1 “Utilization of Whole Bamboo”

In the initial development stage, the bamboo industry often faced a resource efficiency problem, that is, the utilization rate of bamboo raw materials needs to be improved. When only an individual product is produced, the utilization rate of raw materials is very low. For example, when the bamboo raw materials are only used to produce bamboo flooring, the utilization rate is less than 25%, and when it comes to bamboo stick, the utilization rate is less than 10%. Therefore, the “utilization of whole bamboo” is conducive to making full use of bamboo biomass [6].

For example, the middle part of bamboo culms can be processed into bamboo scrimber and bamboo winding composites, the lower-middle part can be processed into laminated bamboo sheets, and the upper-middle part can be processed into bamboo slivers, and then bamboo curtains, bamboo mats and even bamboo mat/curtain boards. The odds/leftovers from the processing of the bamboo stalks can be processed into fiberboards, charcoal, pulp, lumber, fuels, etc., of which the fuels can be formed as biomass fuel pellets. The bases can be processed into charcoal, with bamboo vinegar produced as a by-product in the process. The branches can be used to extract fiber for textile production. The leaves can be used to extract flavone for drink and medicine production.

Most bamboo forests worldwide grow naturally, and some are under intensive management of a few East Asia countries like China and Japan. In the 1950s, under the leadership of ecologists and bamboo experts, China began the research on expansion, high yield, and intensive management of Phyllostachys edulis forests, which enabled the steady expansion of bamboo forest resources and laid the basis for large-scale management. In the 1980s, as the “utilization of whole bamboo” was advocated, a range of products such as artificial bamboo boards, bamboo shoots, bamboo fibers, and bamboo charcoal was successfully developed. At present, China is able to produce a rich variety of bamboo products, involving nearly 10,000 types of 10 categories (Table 2.3; Fig. 2.4).

Table 2.3 Utilization examples of each part of a bamboo plant

Full size table

As reported by INBAR, the measures of integrating and adding value to bamboo resources brought the benefits of product development and marketing in Sanming and Jian’ou, Fujian Province, China. Fujian Province has about 1 million hectares of bamboo forests, most of which are Phyllostachys edulis ones, where many factories gather within a few kilometers to share forest resources. For example, the bamboo shoot companies harvest edible shoots in spring and different types of bamboo processing factories share felled bamboos for the production of various products such as bamboo furniture, safety helmets, bamboo flooring, etc. The older parts that are not suitable for use as raw materials of the above products in the bamboo forests are sold at lower prices to other factories to extract lignin which can serve as dispersant and enhancer for ceramics and dyes, with the remaining fiber to be used for pulp papermaking, and the odds/leftovers from processing in the above fields, such as bamboo sawdust, can be developed into value-added products. An activated carbon company, for example, processes the foregoing odds/leftovers into more than 30 different bamboo charcoal products for application in room deodorization, drinking water purification, and other fields. According to a survey in 2019, the above factories processed up to about 1 million tons of such old bamboo culms per month, with the bamboo-derived activated carbon output reaching 40,000 tons. The final bamboo waste in combination with crop residues is converted into fuel pellets to provide power for the factories [7].

2.2.2 Bamboo-Based Panel Production and Product System

As a non-wood forest product, bamboo grows fast and accumulates more woody biomass than most fast-growing wood species at the same time, so it has a speed advantage in the raw material regeneration stage. In the form of bamboo-based board or bamboo-based square, bamboo is regarded as an ideal substitute for timber in construction and other fields such as furniture, packaging, and transportation. According to literature, the world’s first bamboo-based panel appeared in China in the 1940s, but it was not until the 1980s that the research and development of bamboo-based panel made a breakthrough on the basis of wood-based panel processing technology.

By production technology, typical bamboo-based panels are classified into plybamboo (bamboo mat/curtain board), laminated bamboo, bamboo particleboard, bamboo-oriented strand board, and bamboo scrimber, as well as flattened bamboo panel which is sometimes not regarded as modified bamboo because there is no adhesive added in the production process. Due to different assembly methods, molds, and size specifications, various boards may differ to some extent from each other, and can also be processed into composite boards with wood, plastic, steel, glass fiber, concrete, and/or the like materials. In terms of product segmentation, dozens of types of bamboo-based panels have been developed [8] (Fig. 2.5).

However, among the different types of boards, only bamboo mat/curtain board, laminated bamboo, and bamboo scrimber have been applied on an industrial scale and enjoy market-oriented product promotion for various end uses. Other technologies are either at different stages of research and development or are used for initial production in the laboratories, due to many reasons such as commercial infeasibility of technology, lack of labor supply and bamboo raw material supply at a stable price, insufficient understanding of the multi-link environment and social-economic benefits of “substituting wood with bamboo”, and so on.

The patents for laminated bamboo in the 1990s and bamboo scrimber in the 2000s were mainly developed from China. Comparatively, there are many processing steps, especially for laminated bamboo. On the part of laminated bamboo production, the bamboo culms with large diameters are the suitable raw materials, such as Dendrocalamus giganteus or Dendrocalamus membranaceus. The production steps include cross-cutting—sawbuck—force planing—boiling—drying—finish planing—selecting—glue spreading—laying up—hot pressing—surface planing—side planing—longitudinal tongue groove molding—transverse tongue groove molding—sanding—painting—checking—packaging, and others [9].

The production equipment and labor data provided in 2001 by a manufacturer with an annual output of 40,000 m² of laminated bamboo sheet flooring in southern China show that its production process requires as many as 55 employees. In recent years, even though the technology advances, the industry still faces problems like intensive labor and a low degree of mechanization. At that time, the cost of laminated bamboo sheet per square meter was USD 12.4, of which bamboo materials, chemicals, water and power, wages, manufacturing costs, and other materials were USD 6.5, USD 2.5, USD 0.7, USD 1.4, USD 0.8, and USD 0.5 respectively, and it is clear that bamboo raw materials, chemicals, and wages (i.e., labor) account for the main part of the cost. As for raw material consumption, every 10,000 m² of bamboo flooring require 1,250 tons of bamboo, 3 tons of UF adhesive, 0.125 tons of polyvinyl acetate emulsion adhesive, 0.03 tons of ammonium chloride (NH₄Cl), 2 tons of paint, and 0.1 tons of other chemical materials, where about 50% of bamboo raw materials are wasted or recycled and converted for other uses [9].

Bamboo scrimber was developed in China and, as generally believed, mature technologically in the 2000s. Its technology experienced three stages [10]. In the late 1980s, with reference to wood scrimber technology, bamboo scrimber was successfully prepared in the laboratory by hot pressing. Due to the low-pressure molding process, the product has a low density (< 0.9 g/cm³) and has many defects, such as poor bonding strength, rough surface, serious crack, and poor dimensional stability. When the external temperature and humidity change, the compressed bamboo partially or wholly recovers due to shape memory.

At the end of the 1990s, the development of high-pressure molding process, special molds, and cold pressing and hot curing method made possible the high-density (> 1.0 g/cm³) products and large-size (length × width up to 6,000 mm × 2,500 mm) products. However, the bamboo bundle separation process which was not yet mature led to the problems such as insufficient separation, uneven moisture content, uneven resin distribution, and residual outer layer and inner layer. To improve the moisture resistance and dimensional stability of the product, high-temperature heat treatment, vacuum-pressure impregnation, and other processes were introduced, but because of too high temperature and a too long time in the course of heat treatment, the mass loss rate of bamboo bundles reached 10–20% and the other problems occurred, including large energy consumption, increased cost, and greatly decreased mechanical properties of the product.

In the 2000s, the adoption of fiber in situ controllable separation technology gives birth to the longitudinally continuous and transversely interwoven reticular fiber veneer, the application of cascade resin introduction technology enables the resin to enter through the crack formed by fluffing into fiber cell cavity, wall, pit, and other different tissues, and the introduction of differential asynchronous spot-cracking minimally invasive technology helps effectively destroy the waxy layer and siliceous layer on the surface of bamboo. Such process can help skip the step of removing the outer layer and inner layer of bamboo, improve the production efficiency and raw material utilization, and enable the product performance to be controllable by adjusting material density, adhesive dosage, molding temperature, time duration, process steps, and other conditions according to product performance objectives.

Some countries in Southeast Asia have gradually introduced bamboo processing technology in recent years. For example, Vietnam has been able to produce laminated bamboo sheets and bamboo scrimber products. However, in the areas where the bamboo industry has not yet fully developed, obtaining sufficient raw materials may be a challenge, so the size of companies and factories usually depends on the capacity to obtain raw materials.

2.2.3 Bamboo Damage and Preservative Treatment Technology

2.2.3.1 Damage Types

For raw bamboos, most species have very poor natural durability and a short life span. Researches conducted by FRI (Forest Research Institute) of Dehradun, India, and by scholars from China, Indonesia, and the Philippines show that the average life span of bamboo in these countries is only 1–2 years when exposed to the air or touching the ground, and is expected to reach 3 to 5 years when covered and separated from the ground, or even 6–8 years when used indoors. Under special circumstances, for example, when used in a kitchen in a rural area, the “maintenance” from smoking can prolong the expected life span to 10–15 years. The causes of bamboo damage can be roughly attributed to abiotic and biological factors, and bamboo is particularly vulnerable to damage from biological factors.

2.2.3.1.1 Abiotic Factors

They are mainly burning and cracking. In terms of combustibility, bamboo has a similar chemical composition to wood, so it has similar combustion characteristics, except that raw bamboo burns more quickly because of its hollow form. With regard to cracking, water molecules in the air can be absorbed by bamboo due to moisture absorption caused by the free hydroxyl (–OH) of bamboo cellulose and hemicellulose, and then, under a certain temperature and humidity, evaporates from the bamboo to the air, causing dry shrinkage, thus leading to warping and cracking. The form of cracking depends on bamboo species, bamboo age, raw bamboo diameter, and different dry shrinkage rates (tangential and radial dry shrinkage rates are 3–4 times of longitudinal dry shrinkage rate) due to uneven density [11]. Usually, the cracks extend from the outer layer to the inner layer.

In the 1990s, with the rise of bamboo furniture in China and its spread all over the world, a number of products are cracked under different climatic conditions in other countries, because no solution was adopted to prevent the cracking before transportation, such as drying or tying with steel hoops. Although wood furniture also faced such problems, there were mature methods available to address it. Therefore, to make the bamboo products adapt to different climatic conditions in practice, it is necessary to solve the problem of thermal expansion and contraction of bamboo in different periods over the years. In view of this, it is a must to figure out the internal moisture content of bamboo, and the transmission mechanism of moisture content in the long-term dry and wet alternation course, and find out the right solutions. For example, edge sealing can improve the aging resistance of bamboo plywood.

2.2.3.1.2 Biotic Factors

The chemical composition and content of bamboo cell wall are similar to those of hardwood, but the contents of non-cell wall substances, such as starch, reducing sugar, protein, fat, minerals, etc., are much higher, easy to become the nutrient basis of insects (i.e., beetles and termites) and, especially, molds (i.e., brown rot fungi, white rot fungi, and soft rot fungi) [12]. In addition, bamboo culms do not contain the natural toxins inherent in hardwood or many other tree species. These factors make bamboo less resistant to the said organisms (Fig. 2.6).

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Insect damage

Insect damage is generally found in raw bamboo. For dried bamboo, the main pests are beetles, that is, borers of the order Coleoptera, such as Powderpost beetles, Bostrychidae, Lyclidae, and Cerambycidae, as well as Dinoderus minutus, Dinoderus japonicus, Bostrychopsis parallela, Parabostrychus sp., Lyctus brunneus, Lyctus sinensis, Chlorophorus annularis, Purpuricenus temminckii, etc. The best temperature range for borer larvae is 20–30 °C. When it is lower than 10 °C or higher than 35–38 °C, their activities are greatly reduced. When it is lower than 0–5 °C or higher than 40–45 °C, they stop growing and enter a dormant state. When it is lower than −5 °C or higher than 48–52 °C, they may die in a short time [13]. In addition, the other main pests include termites, such as Subterranean termites and Drywood termites [12].

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Mold growth

Bamboo is vulnerable to such molds as Mucor, blue mould, Trichoderma, Aspergillus, Cladosporium, etc. The damage caused by molds to bamboo includes two ways: staining and structural decaying.

Staining molds mainly feed on non-cell wall substances. They do little harm to cells and hardly affect bamboo strength, but the color hyphae, spores, and pigments secreted by them may stain bamboo surface blue, brown, or gray, which is difficult to eliminate even with bleach or by knife scraping.

Decaying fungi can secrete hydrolases harmful to cellulose and hemicellulose, such as cellulose incision enzyme, cellulose excision enzyme, -glucuroide, β-xylan excision enzyme, β-xylan incision enzyme, β-xyloside, and 1,4-β-mannase, etc., or secrete lignin decomposing enzymes, such as lignin peroxidase, laccase, manganese-dependent peroxidase, etc., which can obtain nutrients by degrading (decomposing and digesting) cellulose, hemicellulose, and lignin, thus causing damage to cells and reducing bamboo strength (Fig. 2.7).

According to Guangjin Wu’s research conducted from 1990 to 1993, there are about 20 decaying fungi, 12 of which are common ones, namely Penicillium corylophilum, Penicillium janthinellum, Penicillium digitatum, Penicillium expansum, Rhizopus nigricans, Aspergillus niger, Trichothecium roseum, Fusarium lactis, Fusarium javanicum, Fusarium moniliforme, Aspergillus flavus, and Penicillium chrysogenum [14].

Most staining molds and decaying fungi appear in the temperature range of 10–40 °C, preferably 20–30 °C. For Penicillium and Fusarium, the optimum temperature is 25–30 °C. For Trichothecium roseum, 20–25 °C is favorable and > 35 °C is not suitable for growing. In terms of humidity, Fusarium germinates when the relative humidity is > 40%, while other fungi germinate when the relative humidity is > 63%. The germination rate increases with the increase of the relative air humidity, with the most suitable relative air humidity being about 93%. With regard to pH, although the optimum pH is about 5, some acid- or alkali-resistant species can survive in the extreme range of pH 1.5 to pH 11. In addition, researches also show that most molds require a moisture content of more than 20%, but with the exception of some soft rot fungi, the reproduction of most molds is inhibited when the environment is saturated with water [13, 14].

2.2.3.2 Protection Treatment

The purpose of bamboo protection is to create an environment in which borers and molds cannot perform their physiological functions. The corresponding methods need to be based on bamboo production conditions, such as processing flow, production environment, product value, and use. There are physical methods and chemical methods.

(1)
Physical methods

The physical methods include steaming/boiling, immersing, drying, electromagnetic radiation, and air conditioning. By steaming/boiling it means heating bamboo to dissolve some soluble nutrients and also eliminate borers and molds. Immersing means dunking bamboo in freshwater to dissolve some soluble nutrients and also inject free water into bamboo cells to create an anoxic environment. Drying refers to heating bamboo with fire or sunlight to directly kill borers or molds or at least reduce moisture content so as to make the environment harder for them to survive. Electromagnetic radiation, including far-infrared ray (25–199 μm) and microwave (10³–10⁵ μm), can cause resonance absorption of molecular vibration and rotation inside bamboo, and simultaneously heat the inside and outside of bamboo to a temperature higher than the tolerance limit of borers and molds, while ultraviolet ray (4–400 μm), X-ray and R-ray can eliminate borers and molds by destroying the internal bioactive substances. Air conditioning is to control the air composition of the bamboo storage environment to reduce oxygen content so that molds cannot survive and borers are suffocated.

(2)
Chemical methods

The chemical methods refer to the use of insecticides and fungicides, mainly organic and inorganic compounds. Organic compounds include halogenated hydrocarbons, phenol and derivatives, organophosphides, carbamic acid esters, pyrethrins, quaternary ammonium salts, hitriles, metal-organic compounds, thiocyanates, carboxylic acid and carboxylates, etc. Inorganic compounds mainly include CuSO₄·5H₂O, Na₂Cr₂O₇·2H₂O, CrO₃, Na₂HAsO·2H₂O, As₂O₅·2H₂O, H₃PO₃, Na₂B₄O₇·10H₂O, Na₂·B₈O₁₃·4H₂O, B₂O₃, NaF, Na₂SiF₆, ZnCl₂, ZnSO₄, HgCl₄, NH₃·H₂O, etc. In practical applications, a combination of more than one chemical is often used to achieve multiple purposes. The general requirements for chemical selection are: convenient methods, available chemicals, and low cost; effective and long-lasting effects; no pollution or pollution control at an acceptable level; little impact on the appearance and texture of bamboo, but in fact, no chemicals can meet all of these requirements [13].

It is generally believed that physical methods are more environmentally friendly. However, physical methods may be temporarily effective, but they cannot prevent the bamboo from reoccurrence of biological damage in subsequent processing, transportation, and storage. In practice, physical methods are often combined with chemical methods, but at present, the chemical treatment process of bamboo, especially modified bamboo, is often criticized. Now, there is no unified material treatment method in the world. In many Southeast Asian countries, the pools with highly toxic drugs, including benzene and others, are used for chemical treatment, without any recycling measures at the production terminal. This is undoubtedly environmentally unfriendly, but the bamboo products may still be used by children. The bamboo treatment with chemicals calls for more researches on environmentally friendly material technology.

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Biological hygrothermal prediction and prevention method

To some extent, the method can be classified as a physical method. Fraunhofer IBP of Germany developed a biohygrothermal model to assess the growth of molds under transient hygrothermal boundary conditions [15]. By the method, the transient boundary conditions obtained from simulation are compared with various typical mold growth conditions of building materials. Specifically, the water balance state of mold spores is modeled and compared with the critical moisture content at which the spores can germinate. If the spore germination conditions are satisfied, the subsequent mycelial growth intensity is assessed according to the previously determined mold growth curve.

Based on the above theoretical model, Fraunhofer IBP also developed a computer program that can predict the formation of molds. The prediction method is based on the comparison between mold growth conditions and transient hygrothermal conditions of buildings, taking into account three biological prerequisites for mold growth (namely temperature, humidity, and substrate). The program contains two continuous prediction models, specifically isopleth model and transient biohygrothermal model. The isopleth model is used to determine the spore germination time and mycelial growth rate according to different isopleth systems. The isopleth systems also take into consideration the influence of the material substrate. It describes the hygrothermal prerequisites for mold growth, including the boundary temperature and relative humidity curve of mold activity stimulation, the isopleth group of spore germination time, and the isopleth group of mycelial growth rate (growth per unit time).

2.2.4 End Utilization Technology

From the perspective of “circular economy”, the upstream and downstream technologies of bamboo processing and utilization cannot work in isolation. A certain bamboo product must be a part of the whole circular value chain and, in particular, waste utilization and by-product processing are required as much as possible. For example, when bamboo scraps are used to produce bamboo charcoal, bamboo vinegar, alcohol, and tar can also be extracted. Ideally, a “zero-waste value chain” should be realized, in which end bamboo utilization technology is particularly important. The following specifically introduces two technologies closely related to the focus of this book, involving biomass utilization and carbon storage in end bamboo products.

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Bamboo charcoal

The end bamboo can be processed into biomass energy, such as bamboo charcoal, briquette, natural gas, etc., or directly burned. Among them, bamboo charcoal-based products, including biochar and activated carbon, have been marketed in the fields of daily necessities and hygiene. For example, in Zhejiang, China, the odds/leftovers from bamboo processing are used to produce bamboo briquette charcoal. Bamboo briquette charcoal enjoys special benefits, such as smokeless combustion; a high calorific value of up to 8,000 kcal/kg; high efficiency of burning for 4 h; and better uniformity than wood charcoal. The raw materials for bamboo charcoal production can be odds/leftovers from bamboo processing, bamboo scraps, low-quality bamboo, etc., widely sourced and cheap. The main processing flow includes bamboo crushing and smashing, qualified bamboo powder (after grinding and screening), drying, shaping (semi-products), carbonizing, checking, selecting, packaging, storage, and sale. The required production equipment mainly includes a mill, screening equipment, drying equipment, shaping equipment, carbonization equipment, an auxiliary product recovery device, and by-product (bamboo vinegar) recycling devices. According to the data of a manufacturer in Anji, Zhejiang Province in 2015, the ratio of the final product to the raw material is about 1:6, containing about 10% bamboo vinegar [16] (Fig. 2.8).

In addition, biochar is regarded as a persistent carbon pool. The draft United Nations Framework Convention on Climate Change of Copenhagen Conference in 2009 includes a plan of using biochar to improve land carbon sinks, stating that “consideration should be given to the role of soils in carbon sequestration, including through the use of biochar and enhancing carbon sinks in drylands”. Biochar is a highly stable carbon compound formed by heating biomass at 350–600 °C while isolating oxygen. Through pyrolysis, up to 50% of carbon can be stored in biochar, and the rest is converted into energy and fuel [17]. When biochar is mixed into the soil, it can not only serve as an effective fertilizer but also reduce the emission of greenhouse gases such as methane and nitrous oxide in the soil. In addition, it has long-term effects in improving soil productivity, maintaining nutrients, increasing plant water use efficiency, and providing potential benefits to microorganisms. Researches have shown that the average residence time of biochar exceeds 1,000 years [17]. Biochar is feasible for developing countries and many rural households to benefit from technology investment.

(2)
Bamboo biomass pellet

Wood pellets can be burned in existing power plants to generate biomass energy, thus widely welcomed by European Union countries and regions, etc., which provides a reference for the utilization of odds/leftovers from bamboo processing. The global wood pellet industry saw an increase from 18.1 million tons in 2012 to 39.6 million tons in 2019 and expects continuous growth in the next few years [18]. In the countries and regions where bamboo grows, to reduce wood logging, many governments have turned to bamboo as a substitute for the fast-growing household wood fuel to reduce the pressure on existing forest resources. 1.2 kg bamboo can generate 1 kWh electricity, which is similar to wood in efficiency, and better than other commonly used powdered biomass such as peanut shell, coffee husk rice husk, etc. [19].

Biomass pellet production unit has some advantages, such as carbon neutrality, a high calorific value of up to 4,500 kcal/kg, no additives, low sulfur (0.08%) and ash, and no need of coal feeder, suitable for boilers and furnaces. With these features, it may be the potential best substitute for coal, and even used in existing coal stoves slightly modified in practical application. The main processing flow includes preparing raw materials, pulverizing, drying (modulation), forming into pellets, cooling down, and package [16]. The raw materials of bamboo biomass pellet can be bamboo waste produced during the production of other bamboo products, such as laminated bamboo or bamboo scrimber (Fig. 2.9).

2.3 Economic, Social, and Environmental Impacts of Bamboo Industry

Bamboo is considered to be directly relevant to 7 of the 17 UN Sustainable Development Goals (SDGs) (1. End poverty, 7. Affordable & clean energy, 11. Sustainable cities & communities, 12. Sustainable consumption and production, 13. Climate change, 15. Life on land, 17. South-south cooperation). It may potentially contribute to developing the local economy, increasing employment, alleviating poverty, and improving the natural environment and human settlements.

2.3.1 Climate Challenge and Bamboo Forests as Carbon Sinks

The Paris Agreement signed at the United Nations Headquarters in 2016 arranges the post-2020 global climate actions. One hundred and ninety-five parties to the Paris Agreement pledge to limit global warming to well below 2 °C, preferably to 1.5 °C, compared to preindustrial levels. According to the Intergovernmental Panel on Climate Change (IPCC), this goal can only be achieved by removing carbon dioxide from the atmosphere. Reducing deforestation and reforestation are of great significance to achieve climate goals because deforestation contributes to a non-negligible part of global greenhouse gas emissions.

In the Paris Agreement, Reducing Emissions from Deforestation and Forest Degradation (REDD+) is officially recognized as a mechanism to mitigate climate change. The Paris Agreement requires each party to determine how to achieve its climate goals through the Nationally Determined Contributions (NDCs). REDD+ is closely related to two mechanisms established based on the Kyoto Protocol: The Clean Development Mechanism (CDM) and the Joint Implementation Mechanism. Additionally, REDD+ is closely relevant to the voluntary carbon market, including the Voluntary Carbon Standard and the Gold Standard [20].

However, REDD+ is a mechanism targeted at forestry, while agriculture is also a critical option to mitigate global climate change. Some future mechanisms, such as Reducing Emissions from All Land Uses (REALU), may include more land uses contributing to climate change mitigation, for example, expanding the scope from forestry to agroforestry, even agriculture, to suit future plans for climate change mitigation.

Bamboo forests have the potential to play a role in mitigating climate change through these mechanisms. Activities related to REDD+ are complicated and involve multiple aspects, with which bamboo can help are mainly as follows: reducing carbon emissions caused by deforestation, reducing carbon emissions caused by forest degradation, protecting carbon stored in forests, and increasing carbon stocks through sustainable forest management. For example, bamboo may produce materials or biomass energy as the replacement of wood or charcoal, thereby reducing deforestation. Regarding possible future mechanisms like REALU, bamboo forests and agriculture have a lot in common in land use. Bamboo can grow in various types of soil and become part of many production systems. Like perennial crops, bamboo is harvested on a regular basis so that it retains most of the biomass and carbon stocks in the stalk, stem, and root systems above and below the ground.

2.3.1.1 Carbon Sequestration and Carbon Reduction Mechanisms by Bamboo Forests and Bamboo Products

Due to its rapid growth, giant bamboo is considered to be able to effectively absorb carbon dioxide, and further sequester carbon after being harvested and made into durable bamboo products which may replace non-renewable and carbon-intensive products and further reduce carbon emissions. To sequester carbon and reduce carbon emissions through bamboo forests and bamboo products, three mechanisms for calculating the potential amount of carbon sequestration and that of reduced carbon emissions by bamboo must be considered: total ecosystem carbon, durable product pool, and potential product replacement [21]. In general, carbon sequestration includes the carbon sequestered in the ecosystem, which is defined as total ecosystem carbon (TEC), and that sequestered in the harvested bamboo products (HBPs), which is related to the annual carbon sequestration rate. When bamboo is used to replace materials with larger carbon footprints, the potential to reduce carbon emissions will be amplified, which is known as the potential carbon replacement factor of bamboo, and may contribute to further significantly reducing emissions of carbon dioxide.

In the AFOLU (Agriculture, Forestry and Other Land Uses) Sector of the 2006 IPCC Guidelines, bamboo may contribute to carbon sequestration in two ways: forests/plantation forests (Chap. 4, Forest Land) and durable product carbon pool (Chap. 12, Harvested Wood Products) [22]. The mechanisms approved by the Paris Agreement, such as CDM and REDD+ , do not consider reducing carbon emissions through product replacement. However, this may be included in future plans for reducing greenhouse gas emissions, which is particularly important for bamboo products. In addition, if bamboo is used as a source of biomass for generating energy, for example, generating electricity using the latest bamboo gasification technology, to replace energy sources with large carbon footprints, such as fossil fuels, it can be included in the CDM.

A review of the existing literature has shown that, generally speaking, the total ecosystem carbon (TEC) in bamboo forests ranges from 94 to 392 tC/ha, which is lower than that in natural wood forests (126–699 tC/ha), but close to that in plantation wood forests (85–429 tC/ha). Compared with plantation forests of Chinese fir that are also suitable for the production of building materials under similar climatic conditions, the intensively managed forests of Moso bamboo (Phyllostachys edulis) are very likely to be carbon sinks. The TEC in Moso bamboo forests is 168 tC/ha, slightly lower than that in Chinese fir forests, 182 tC/ha. But considering the fact that Moso bamboo grows faster than Chinese fir, the former captures a greater amount of carbon. What’s more, if Moso bamboo is used to manufacture durable products to replace non-renewable, carbon-intensive building materials such as PVC flooring and aluminum window frames, it can further reduce carbon emissions. In terms of the carbon stock in durable products, bamboo is 70.3 tC/ha, and wood 30 tC/ha. In terms of the carbon emissions reduced by-product replacement, bamboo is 57.4 tC/ha and wood 24.5 tC/ha. As a result, the amount of carbon sequestered by intensively managed Moso bamboo forests is 296 tC/ha, higher than that of Chinese fir forests, 237 tC/ha. However, if bamboo forests are not properly managed, the result will turn out to be the opposite. The total amount of carbon sequestered and carbon emission reduced by unmanaged bamboo forests is merely 49.5 tC/ha, which highlights the importance of management [21].

(1)
TEC sinks

According to FAO, the carbon stocks in the world’s forests are distributed as follows: 53% in biomass, 8% in dead wood and dry fallen branches and leaves, and 39% in soil. CDM classifies carbon pools into three categories: above-ground carbon (AGC), below-ground carbon (BGC), and soil organic carbon (SOC), together constituting total ecosystem carbon (TEC). However, the conversion between forest vegetation and non-forest vegetation will not significantly change the carbon content in the soil. The SOC in bamboo forests ranges from 70 to 200 tC/ha, which is close to that in grassland, pasture, and shrubland (66–198 tC/ha) [23]. TEC in bamboo forests varies significantly, depending on bamboo species, growing conditions (temperature, rainfall, soil, etc.), and management measures (emphasis, fertilization, weeding, irrigation, etc.). Bamboo species also play a role, and clumping bamboo performs better in carbon sequestration than running bamboo [24]. For example, Guadua has a remarkably higher amount of biomass than Moso, and its total amount of carbon sequestered and reduced carbon emissions is 401 tC/ha (Fig. 2.10).

However, the potential of bamboos to sequester carbon and reduce carbon emissions should not be overestimated, because their performance is subject to some limitations and the above data is predicted under ideal conditions. For example, even for giant species like Moso bamboo, the amount of carbon sequestered by the same bamboo forest can drop from 5.1 tC/ha per year to 1.65 tC/ha per year without proper management [25]. As time goes by, bamboo forests that have been grown for a long time will lead to a decrease in SOC [26].

(2)
Durable product pool

According to IPCC, “only in the case where a country can document that existing stocks of long-term forest products are in fact increasing”, can it count the carbon temporarily stored in harvested wood products (HWPs) as a net carbon sink. However, data on HWPs usually comes from national and international statistical databases, such as FAOSTAT and UN Comtrade, and usually excludes the data on wood products.

(3)
Potential product replacement

In Climwood 2030 study, potential displacement factor is defined as a (absolute and relative) measure of the efficiency with which the increased use of forest biomass in the production of a given type of functional units would reduce net GHG emissions, over the full life cycle of the functional units under consideration. For example, “Building a timber house instead of an equivalent non-timber house would save X (% of) t CO₂e over the lifecycle of the houses” (Fig. 2.11).

Bamboo biomass can be converted into electricity or heat, such as firewood, natural gas, or charcoal. If they are used to replace fossil fuels, carbon emissions can be reduced. The effect of the replacement depends on many factors, such as the source of energy being replaced, a country’s energy structure, and the way that the bioenergy is produced. Take the potential for reducing carbon emissions by generating electricity using bamboo gasification as an example. The first thing to consider is the production of bamboo-based bioenergy. 1.2 kg of dried bamboo may produce 1 kWh of electricity and 0.06–0.16 kg of bamboo charcoal. After deducting the 0.12 kWh of power consumption by the generator, 0.88 kWh of electricity is left. In other words, 1 kg of bamboo produces 0.72 kWh of electricity and 0.1 kg of bamboo charcoal. Assuming that there is no loss in the process of harvesting Moso bamboo for energy production, that is, all AGC is harvested, the amount of carbon sequestered annually is 5.1 tC/ha [25], which is equivalent to 10.2 t/ha of dry bamboo biomass. As a result, a total of 7,344 kWh/ha of electricity and 1,020 kg bamboo charcoal can be produced. If the electricity generated using bamboo gasification is used to replace that generated from fossil fuels supplied to the Chinese power grid, considering that the carbon emissions generated by the Chinese power grid are 0.925 kg CO₂eq/kWh, 6.8 t CO₂eq/ha of carbon emissions can be reduced (7,344 kWh/ha × 0.925 kg CO₂eq/kWh = 6.8 t CO₂eq/ha). In 30 years, the reduction may reach 203.8 tCO₂/ha or 55.5 tC/ha. Additionally, if bamboo charcoal (assuming the carbon content is 100%) is buried in the ground for at least 30 years, 112 tCO₂/ha or 30.6 tC/ha of carbon may be locked. Therefore, the potential for total carbon emission reduction may reach 86.1 tC/ha. Together with the 168 tC/h of TEC, the total amount may stand at 254.1 tC/ha [21] (Fig. 2.12).

Reducing net CO₂ emissions by replacing fossil-based energy with biomass energy produced with bamboo gasification is not as effective as producing engineered bamboo, because durable engineered bamboo has a long service life and may store an extra amount of carbon. For example, the carbon stock in HBPs made of Moso bamboo in 30 years is 296 tC/ha, and if all the bamboo afforested is harvested from the intensively managed bamboo forests and used for the production of laminated bamboo to replace non-renewable and carbon-intensive materials, 645 to 1,182 tCO₂/ha of carbon may be reduced. The carbon reduction does not include SOC, because it is assumed that the baseline condition before afforestation is grassland with SOC similar to bamboo/wood forests.

However, there is still an obstacle to including bamboo in the NDCs. At present, only TEC may be eligible for NDCs set forth by the CDM. Due to the lack of data on bamboo trade, it is not possible to include HBPs into the national climate policies as a measure to mitigate climate change for now. Therefore, except for adopting voluntary carbon credits in individual projects, it is impossible to include bamboo in the NDCs. This issue also affects the purchase of bamboo and other bio-based building materials to replace carbon-intensive ones commonly used in CDM or REDD+.

2.3.1.2 Afforestation and Bamboo Forest Management Carbon Projects

Bamboo forests may be used to produce materials and restore degraded land, and have remarkable potential for growth on a global scale. The Bonn Challenge, proposed in an international conference held in Germany in 2011, set the goal to bring 150 million hectares of degraded and deforested landscapes into restoration by 2020 and 350 million by 2030 by the New York Declaration. Bamboos are members of the giant grass family. The parent plants consist of many stems and are connected by a huge root system underground. New bamboo culms are grown every year, making deforestation a difficult matter. Due to the well-developed root system, bamboos can grow in non-arable lands to improve soil quality and restore groundwater levels. Like crops, harvesting 4–5-year-old bamboo culms annually is conducive to rapid growth and provides a stable income for farmers. Rapid growth also leads to a high yield of bamboo, which is particularly important as the land may become scarcer in the future. These characteristics make bamboo particularly suitable for afforestation.

In China, the data on the area of bamboo forests, accumulated biomass, carbon stock, and soil organic carbon from the Fifth National Forest Inventory indicates that the carbon stock in bamboo forests increased gradually from 318.55 TgC between 1950 and 1962 to 639.32 TgC between 1999 and 2003, an increase ranging from 6.5% to 11.6% in each inventory cycle. Studies also predict that the carbon stock in bamboo forests will grow to 1,017.64 TgC in 2050 [27].

(1)
Comparison between bamboo forests and wood forests in temperate/sub-tropical zone: Moso bamboo versus Chinese fir [28]

The growth of Chinese fir (Cunninghamia lanceolata) depends on similar climatic conditions favoring that of Moso bamboo. Therefore, they grow in similar areas. Chinese fir forest is one of the fastest-growing plantation forests in temperate/sub-tropical zones of China. But the ways they grow are different. Trees in Chinese fir forests are of similar age and stay in the stage of “young forest” in the first 10 years; while those in Moso bamboo forests are of different ages, and the culms of about 8 years old begin to age and wither. Therefore, bamboo forests in their natural state will quickly achieve carbon neutrality. According to monitoring of a new plantation forest of Moso bamboo, the amount of carbon sequestered by it in the first 10 years is 3.1 t/(ha·yr) (Figs. 2.13 and 2.14).

Comparing the annual net carbon stock in bamboo forests and that in Chinese fir forests in a 60-year cycle, the former reaches the peak of about 5.5 tC/(ha·yr) in the 5th year, and enters a stable state of about 3.8 tC/(ha·yr) after the 10th year with 1/3 of the bamboo culms harvested annually; while the latter reaches the peak of about 5.5 tC/(ha·yr) as well in the 13th year, and drops gradually until being all harvested in the 30th year. In the 60-year cycle, the total carbon stock accumulated in bamboo forests is 217 tC/ha, which is 22% higher than that in Chinese fir forests, 178 tC/ha.

However, bamboo forests that are not harvested regularly perform much poorer in carbon sequestration. Naturally growing bamboo forests contain bamboo of all ages, as well as many senescent or withered bamboo culms, and the root system may also deteriorate. This type of bamboo forest often draws less attention because it is not within the scope of people’s view. FAO 2005 data shows that about 70% of bamboo forests in Asia are naturally growing, and only some of them are managed by communities or entities in forestry. Comparing forests of Chinese fir and bamboo, the carbon stock in Chinese fir forests in the 15th year is 2.13 times that in unmanaged bamboo forests [29]. In the sub-tropical zone, a 30-year simulation shows that the amount of carbon sequestered by the naturally growing bamboo forests is only about 30% of that in Chinese fir forests (Figs. 2.15 and 2.16).

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Comparison between bamboo forests and wood forests in the tropical zone: Ma bamboo versus Eucalyptus [28]

Ma bamboo (Dendrocalamus latiflorus) forests are compared with Eucalyptus (Eucalyptus urophylla) forests in the tropical zone. Ma bamboo is a clumping bamboo that grows widely in the tropical zone. Eucalyptus forests are one of the world’s fastest-growing plantation forests and are characterized by high yield. A simulation based on actual test data shows that the amount of carbon accumulated by Ma bamboo in ten years is 128 tC/ha, which is higher than that by Eucalyptus, 115 tC/ha (Fig. 2.17).

The above studies simulate the amount of carbon sequestered annually by forests of Moso bamboo and Ma bamboo, and compare them with that by forests of Chinese fir and Eucalyptus to demonstrate that bamboo forests are a feasible option of carbon sequestration. With measures such as regular soil management and annual harvesting, bamboo forests may sequester the amount of carbon equivalent to that of fast-growing trees but follow a different pattern. Sustainable management and harvesting are critical for maintaining the capacity of bamboo forests for carbon sequestration.

Additionally, for bamboo forests to play a role in mitigating climate change, efforts should be made not only in the growing and renewal of plantation forests but also in the optimized management of existing bamboo forests so as to enhance productivity and carbon sequestration of bamboo forests at the same time. In this way, it is guaranteed that bamboo forests not only provide effective ecological services but also meet market demand. Therefore, it is necessary to develop a management system targeted at optimizing the capacity of bamboo forests for carbon sequestration. Statistics show that the TEC in the extensively managed Moso bamboo forests is higher than that in intensively managed ones. The carbon stock in arbors ranges from 33 to 74 tC/ha, which is higher than that in the extensively managed bamboo forests ranging from 29 to 51 tC/ha.

2.3.1.3 Voluntary Carbon Credits and Cases in China

To make bamboo a usable resource in national and international policies, it is important for it to be recognized by the United Nations Framework Convention on Climate Change (UNFCCC). UNFCCC was created to help mitigate climate change in accordance with the targets set in the Kyoto Protocol. It establishes the following mandatory mechanisms to reduce GHG emissions: Emissions Trading, Joint Implementation and Clean Development Mechanism.

Some mechanisms have been included in mandatory carbon reduction methodologies, such as CDM and REDD+, while others are only in voluntary ones, for example, VSC. Bamboo may grow on non-arable land, degraded grassland, or eroded slopes. Therefore, it may help some countries in the tropical and sub-tropical zones to achieve their NDCs, among which many also face the pressure of deforestation, especially hardwood forests. Complicated calculations, which are not available for now, are required to recognize bamboo-related carbon sequestration and carbon emissions. Additionally, as bamboo is not considered a type of tree in the forest evaluation system, it is often neglected in discussions about forests and climate change. For bamboo to be accepted by REDD+, each country must first justify that bamboo is a species that sequesters carbon.

At present, there are compliance carbon markets and voluntary carbon markets for emissions trading. The compliance carbon markets pay more attention to large industries with high emission, including agriculture, forestry, and other land uses (AFOLU), where deforestation is particularly serious. In addition to the compliance carbon markets, the voluntary carbon markets have also been developed as promoted by corporate social responsibility, which is usually small in scale and not subject to market supervision but internationally recognized standards such as Verified Carbon Standard and the Gold Standard. In actual researches, bamboo has been recognized in standards such as the Gold Standard, Panda Standard, and Verified Carbon Scheme, but more fundamental efforts are still needed. The carbon stock in bamboo forests varies greatly and needs to be assessed across locations, species, and climatic conditions [25, 28].

To meet the growing demand for carbon sink practices and carbon trading related to bamboo forests, and to mitigate climate change using the potential of bamboo forests, organizations such as INBAR, Zhejiang A & F University (ZAFU), China Green Carbon Foundation (CGCF), and the Research Institute of Subtropical Forestry of the Chinese Academy of Forestry (RISF-CAF) have developed methodologies to incorporate bamboo into carbon-crediting schemes as they recognize bamboo as a fast-growing, renewable, and high-yielding species for carbon sequestration. Carbon Accounting Methodology for Afforestation with Bamboo in China has been developed, providing the basic principles and guidelines for the scope of application, design, qualifications, afforestation practices, selection of carbon pool, GHG emission sources, leakage, and baseline scenarios for bamboo forest projects as carbon sinks, and will be included in the carbon trading or carbon offset programs in China. This methodology is based on the technical documents developed by the State Forestry Administration of China (SFA), as well as the previous experience of INBAR, ZAFU, RISF-CAF, and the experience of the CGCF-funded pilot project of bamboo forests as carbon sinks in Lin’an, Zhejiang. In addition, based on the research of INBAR, the methodology also refers to relevant international standards and regulations such as CDM and VCS [30].

SFA has officially recognized the Carbon Accounting Methodology for Afforestation with Bamboo in China, which will make bamboo qualified for afforestation projects in China and will quantify their respective carbon credits. Chinese carbon trading markets have also responded positively to this new opportunity for carbon offset through bamboo forests. According to the methodology, 46.7 hectares of bamboo forests have been planted in Lin’an, Zhejiang in 2009, and used for carbon offset in China’s voluntary carbon markets. In 2014, the first carbon afforestation project was completed, followed by the development of a forest management carbon project to investigate the sustainable management of bamboo forests. Additionally, attempts have also been made to integrate bamboo into the agro-forestry and agricultural systems. Examples of carbon afforestation projects and forest management carbon projects are as follows [31]:

The first carbon afforestation project: Hubei Tongshan bamboo afforestation carbon project, 700.94 ha in 20 years 131123 tCO₂, equivalent to 187 tCO₂/ha, Moso bamboo, 2015, buyer: Yuedian Group, price: 20 RMB/tCO₂;

The first bamboo forest management carbon project: Fujian Shunchang bamboo forest management carbon project, 2,278.5 ha in 30 years 259,180 tCO₂, equivalent to 114 tCO₂/ha, Moso bamboo, management measures: chopping, weeding, fertilization, bamboo shoots, cutting, forest reclamation, methodology: Methodology for CCER bamboo forest management carbon project, buyer: Zhisheng Chemical Co. LTD, price: 18 RMB/tCO₂;

Lin’an carbon afforestation pilot project: 46.7 ha in 20 years 8155 tCO₂, equivalent to 175 tCO₂/ha, planted in 2008, methodology: China-SFA bamboo methodology, buyer: Alibaba, price: 18 RMB/tCO₂;

Zhejiang Anji bamboo forest management carbon project, 1,426.27 ha in 30 years from 2016 to 2045, 249,658 tCO₂, equivalent to 175 tCO₂/ha, Moso bamboo, management measures: chopping, weeding, fertilization, bamboo shoots, cutting, forest reclamation, methodology: Methodology for CCER bamboo forest management carbon project.

In addition, INBAR, CGCF, ZAFU, and RISF-CAF are developing methodologies for the calculation of carbon around the globe. During the pilot and verification phase, this process ensures that the carbon accounting methodologies comply with the definition of forest and the laws and regulations of countries. More scientific data related to different bamboo species and types of management will also be collected. Small and medium-sized experimental forests will be grown in selected countries. Larger projects may be implemented according to the methodology afterward. However, dedicated bamboo carbon accounting methodologies are still in their infancy and must be further developed and expanded through future research and practice (Fig. 2.18).

2.3.1.4 Development and Use of Low-Carbon Products

Most bamboo species mature in 7–10 years and then age rapidly, releasing carbon from above-ground biomass back to the atmosphere. At the level of ecosystem, the carbon stock in mature bamboo forests is equivalent to or slightly lower than that in other natural forests or plantation forests. However, most matured plantation forests will be completely cut down and the land will be reforested. On the opposite, bamboo forests will be cut down and re-grown on a regular basis and maintain a stable amount of carbon sequestered every year. Processing the harvested bamboo into durable products will sequester the carbon for a long period of time before the bamboo products are degraded. The sequestration period may be extended by improving the durability of bamboo products through technological innovation.

Globally, bamboo and rattan are considered to be the two most important non-timber forest plants. The harvested wood products (HWP) made of harvested bamboo are deemed as “non-timber forest products” which are particularly important for carbon sequestration and carbon emission reduction. During COP17, UNFCCC stressed the importance of HWP carbon pool. Many durable bamboo products such as houses, floors, and furniture can store carbon for a long time. Because of the rapid growth and renewal of bamboo, HWP may store more carbon than the products made of timber if bamboo is managed and harvested in a sustainable way. However, there is no defined carbon accounting methodology, especially for the voluntary carbon markets. Therefore, it is necessary to develop methodologies to enable stakeholders to obtain voluntary carbon credits for durable bamboo products in the form of HWP (Table 2.4).

Table 2.4 Carbon footprint comparison between bamboo and other common industrial materials

Full size table

2.3.2 Land Resources and Ecological Restoration

Studies show that the underground roots of bamboo forests per hectare can be as long as 100 km and as deep as 60 cm, and can survive for up to a century. What’s more, due to their rapid growth, bamboo forests can quickly restore lands where the above-ground biomass is destroyed (by fire, for example). It has been proven that about 1/6 to 1/3 of the total bamboo stalks in intensively managed bamboo forests can be harvested annually, and continuous harvesting can provide space for bamboo forests to maintain efficient growth. A research report by FAO and INBAR on China, India, Nepal, and other countries shows that in India, planting bamboo in a land parcel that was severely degraded due to the intensive brick manufacturing results in an increase in the groundwater level by 10 m in 20 years; in Nepal, bamboo plantations have been proven to be effective in reducing soil erosion and flood damage; in Chishui, China, the surface runoff in bamboo plantations is 25% less than that in nearby sweet potato farms [32] (Fig. 2.19).

The Asia-Pacific region is the most densely populated region in the world, where more than half of the world’s total population resides. Due to the high population density, small land area per capita, and lack of arable land, it is impossible to plant bamboo on lands that produce food. As a result, only mountains, steep slopes, barren, or degraded lands that are not suitable for cultivation are available for bamboo planting. This is often incorporated into regional land restoration policies. For example, China has implemented many such projects.

Land restoration in Anji County. Like some other places in China, Anji County has experienced decades of deforestation and agricultural practices. In the 1980s, farmers reclaimed barren hills and wasteland to plant chestnuts and tea. However, the unsustainable planting and farming aggravated land degradation, soil erosion, polluted water, and reduced the capacity of soil to retain water. This led to disasters such as water and soil loss, landslides, and mudslides during the rainy seasons (May/June and August/September). Since 2008, Anji County has been implementing a landscape modification project, in which bamboo is a key element. In the project, broad-leaved trees and bamboos have been planted in 1,800 hectares of land originally growing walnut forest and 537 hectares of land originally growing coniferous forest. Selected bamboo species include Moso bamboo (Phyllostachys edulis), P. iridescent, and P. nigra. In 2010, the amount of soil loss in Anji County was 561,000 tons, down by 49.2% compared to that in 1999.

Land restoration in Chishui. Chishui City in Guizhou Province, China is located on the upper reaches of the Yangtze River, and experienced severe floods and soil and water loss at the end of the twentieth century. Since 2001, it has been restoring land by planting bamboo forests. The comprehensive assessment of the vulnerability of several main bamboo forests in Chishui shows that the adaptability of bamboo to the environment varies by species. Bamboos are adaptive to environmental temperature rise, but in general slightly vulnerable or mildly vulnerable. Specifically, as the temperature rises, the density of bamboo stem, diameter at breast height (DBH), and biomass of Moso bamboo (Phyllostachys edulis) and Dendrocalamus farinosus increase, and their vulnerability decreases. On the contrary, the density of bamboo stem, DBH, and biomass of Bambusa rigida, Bambusa pervariabilis, and Neosinocalamus affinis decrease, and their vulnerability increases. As the rainfall rises, the DBH of Moso bamboo increases, while that of Dendrocalamus farinosus, Bambusa rigida, Bambusa pervariabilis, and Neosinocalamus affinis decreases. The growth of Moso bamboo roots features hydrotaxis, phototaxis, and fertilizer-taxis. The length of most stems ranges from 25 to 35 cm, most affected by temperature, followed by precipitation. In 2018, the lands restored by bamboo forests saw a decrease of 25% in the average runoff and a decrease of 80% in the amount of soil erosion. Each hectare of bamboo forest conserves about 6,000 m³ of water and sequesters 40,000 tons of carbon. The monitoring of 30,000 hectares of bamboo forests shows that the amount of slit flowing into the rivers annually is reduced by 350,000 tons [33].

2.3.3 Economic and Social Impacts of Bamboo Industry

2.3.3.1 Bamboo Industry in China

Bamboo species are divided into clumping bamboo and running bamboo defined by their rooting characteristics. Clumping bamboo species in China are mainly in Bambusa and Dendrocalamus genera, distributed in the southern subtropical zone and the northern edge of the tropical zone. Running bamboo species are mainly in Phyllostachys and Indosasa genera, distributed in the central and northern sub-tropical zones. In China’s vegetation classification, bamboo is in the broad-leaved vegetation group. There are three types of bamboo forests: temperate bamboo forests, warm temperate bamboo forests, and tropical bamboo forests.

In China, there are five major bamboo zones and six sub-zones [13]: (Fig. 2.20)

I.
Running bamboo zone in northern China. The region includes southeastern Gansu, northern Sichuan, Shanxi, and southern Shandong, southwestern Hebei, Henan, and Hubei. There are about 29 bamboo species in 10 genera, mainly running bamboo species in Bashania and Phyllostachys genera. The region can be further divided into three natural areas: the northern subtropical warm and humid area in the upper reaches of Huai River and Han River; the warm and semi-humid area in the middle and lower reaches of Yellow River; and the temperate semi-arid warm area at the junction of Shanxi, Gansu, and Ningxia.
II.
Mixed bamboo zone in the south of Yangtze River. The region includes Sichuan, Hunan, Jiangxi, southeastern Zhejiang, and northwestern Fujian (between 25 and 30°N). There are running bamboo species in Phyllostachys, Indocalamus, and Pleioblastus genera, and clumping bamboo species in Sinocalamus and Bambusa genera. It is where Moso bamboo mainly grows. The region has a large area of plantation forests and a developed bamboo industry.
III.
Mountain bamboo zone in southwestern China. Located near Hengduan Mountain Range, the region includes southeastern Tibet, northwestern and northeastern Yunnan, southwestern and southern Sichuan, at an altitude of 1,500–3,800 m or even higher. There are clumping bamboo species mainly in Fargesia and Yushania genera, and occasionally in other genera such as Indocalamus, Chimonocalamus, and Chimonobambusa.
IV.
Clumping bamboo zone in southern China, divided into South China and Southwest China sub-zones.
1. IVa.
  South China sub-zone: Located between the southern sub-tropical monsoon evergreen broad-leaved forest belt and the tropical seasonal rain forest belt, the sub-zone includes the area from southern Guangdong to Nanling Mountains, Fujian coastal area, and Taiwan. There are clumping bamboo species in Bambusa and Schizostachyum genera. The sub-zone is where many bamboo species in Bambusa genus mainly grow, and where some mixed rooting bamboo genera like Sinobambusa grow.
2. IVb
  Southwest China sub-zone: It includes western Guangxi, southern Guizhou, and most areas of Yunnan. There are clumping bamboo species in Dendrocalamus, Gigantochloa, Cephalostachyum, and Thyrsostachys genera. The sub-zone is where bamboo species in Dendrocalamus genus mainly grow.
V.
Climbing bamboo zone in Yunnan and Hainan. The region includes central and southern Hainan Island, and the border areas in southern and western Yunnan, and the border area in southern Tibet. There are clumping and climbing bamboo species in genera Melocalamus, Dinochloa, and Schizostachyum, and occasionally Bambusa.
VI.
In terms of vertical distribution, generally speaking, clumping bamboo species in genera such as Bambusa, Dendrocalamus, and Schizostachyum dominate low-altitude areas where some climbing and lianoid species also grow. The genera in high-altitude areas are mainly Borinda, Fargesia, Yushania, and Thamnocalamus. Species in Chimonobambusa genus and its sub-genus Qiongzhuea are mainly distributed in middle-altitude areas.
(1)
“Substituting wood with bamboo” policies

There is a huge gap in wood supply in China, and the country imports wood equivalent to over 200 million cubic meters of logs annually. Finding and developing wood alternatives become a top priority, and bamboo may be one of the ideal alternatives. It takes 3 to 5 years for bamboo to mature, much faster than softwood and hardwood, and also significantly faster than general fast-growing tree species that take 10 to 15 years to mature. China produces 2.72 billion bamboos annually (2017), which is equivalent to more than 40 million cubic meters of bamboo materials and has the potential to bridge the gap in demand for wood.

Back in the 1970s, China proposed to “substitute wood with bamboo” and in the 1980s and 1990s, it further proposed the concept of “bamboo-wood composites”. In the twenty-first century, it has begun to developed policies that promote the development of bamboo buildings and related industries. Specifically, in 2005, the National Development and Reform Commission and other departments issued the Comments on Accelerating the Promotion of Wood Saving and Replacement. The fourth point “Developing Wood Alternatives and Optimizing the Structure of Wood Consumption” of the “Key Links of Work” section in the document states: “It is advocated and encouraged to produce and use wood alternatives. Priority should be given to the use of economic, durable, recyclable and eco-friendly wood alternatives and their products to reduce unreasonable consumption of wood. Wood-based boards and processed products made of crop residues, bamboo and etc. should be developed to replace wood products and implement projects of environmentally-friendly wood replacement. Recyclable non-wood materials should be prioritized in urban and rural construction…” In 2015, the Ministry of Industry and Information Technology and the Ministry of Housing and Urban-Rural Development jointly issued the Action Plan for Advocating the Production and Application of Green Building Materials, stating that, “It is encouraged to develop bamboo building materials and bamboo buildings in areas having abundant bamboo resources.”

(2)
Intensive management and industrial utilization of bamboo forests

In 2001, the Central Committee of the Communist Party of China issued the Opinions of the Central Committee of the Communist Party of China and the State Council on Comprehensively Promoting the Reform of the Collective Forest Tenure System (Document [2008] No. 10) to comprehensively reform the contract-based management of forest land in collective forest areas. In addition, China provides subsidies for bamboo afforestation, aiming to increase the income of workers in the bamboo industry and promote the development of the industry. This has mobilized the bamboo farmers to manage bamboo forests to a certain extent. Yong’an, one of China’s Top Ten Bamboo Cites, has 61.2 thousand ha of bamboo forests, which accounts for 29.6% of the total forest area, and has 0.4 ha of bamboo forests per capita, ranking first in China. It has 76 native bamboo species in 15 genera. In 2017, the output value of bamboo industry in Yong’an was RMB 6.62 billion, and the income per capita from the industry accounted for 37% of the disposable income of rural residents in the city.

Moso bamboo is the dominant bamboo species in China. It usually grows in sub-tropical areas with an average annual temperature of 16–20 °C, rainfall of 1,000–2,000 mm, and a humid climate. Soil with great permeability is required, and suitable options include acidic and neutral purple, yellow, and reddish-yellow soil. This bamboo species grows in Yangtze River basin and provinces in southern China, extending from Taiwan to the west to Yunnan, Guangdong, and Guangxi to the north to northern Jiangsu, Anhui, and even southern Henan. Diverse types of terrain such as mountains, hills, and plains are available for planting. In general, the density of Moso bamboo forests is 1,500–4,200 stalks/ha, about 3,000 stalks/ha on average. The diameter is 11.6 cm on average, up to 20 cm, and the height is 18 m on average, up to 22.5 m. The aboveground biomass is between 50,850 and 233,460 kg/ha, of which bamboo stalks account for 70–75%. The average weight of a single stalk is 35 kg [13]. In the 1970s, after careful R&D, China initiated the Project of “South-to-North Transfer of Bamboos” to introduce (Moso) bamboo shoots to Shandong, Hebei, Henan, and northern Qin Mountains [13].

Since the 1970s, China’s bamboo industry has focused on the industrialized utilization of bamboo and developed more valuable products. At present, there are over 100 series consisting of about 10,000 kinds of products widely used in such fields as construction, furniture, packaging, papermaking, food, textiles, and chemicals. For the wood-based board industry, China has a variety of bamboo species that may be used as raw materials, including: Phyllostachys edulis, the most successfully researched and developed temperate bamboo in the world, which has high economic value and can be used to produce bamboo-based boards and bamboo shoots; Dendrocalamus giganteus, a type of giant clumping bamboo, which is as high as 30 m with DBH of 30 cm, most widely planted in tropical areas in Yunnan, has coarse fiber and can be processed into bamboo flooring; Dendrocalamus sinicus, the largest bamboo documented in the literature, which may grow as high as 30 m or more with DBH of 35 cm; Indosasa sinica, which is a type of medium to large bamboo mainly distributed in southwestern China with height of 16–22 m and DBH of 8–14 cm, and can be used to produce building materials or bamboo shoots; Schizostachyum funghomii, which is distributed from southern to southwestern China with DHB of 8–10 cm and internode of 60–120 cm; Fargesia spp., a dominant bamboo species in high-altitude areas in southwestern China, which can be used to make paper or particle boards [13].

(3)
Challenges

China is promoting “green buildings”, “green building materials”, “prefabricated buildings”, and “new rural construction”, which brings opportunities for the development of bamboo industry and bamboo buildings, while at the same time, also poses challenges. The entire industrial chain involves the cultivation and management of bamboo resources, bamboo processing and utilization, bamboo building design and construction, etc. Expertise in these areas must be developed and improved.

In China, a large number of bamboos are grown in mountainous areas. At present, as there is no sophisticated machinery or technology available for mechanized and scale harvesting, manual operation is basically the only option. But the rising labor costs will lead to a competitive disadvantage in price. The production process is also labor-intensive. The transportation, round bamboo cutting, slicing, stripping, weaving, and unwinding during the processing process involve the manual operation of machines, and other steps such as unit drying, sizing, mat formation, hot pressing and forming also require manual operation. Compared with the technology used in the international wood industry, the bamboo processing and utilization technology in China’s bamboo industry is not automated and continuous enough. The scale of industrialized production is small, and most of the enterprises producing and processing bamboo products are SMEs vulnerable to risks. What’s more, their limited capacities for precision and customized processing lead to the low added value of products that are homogenous and applied in only a few areas of bulk products like bamboo flooring. In addition, durability and fire resistance still restrict the wide application of bamboo.

In the process of development, some bamboo forests are overdeveloped for short-term economic benefits which have led to declining long-term productivity and ecological protection and the loss of biodiversity of bamboo forests [34]. The biomass and nutrient accumulation in Moso bamboo forests are the main parameters that characterize their structure and function, and systematic productivity and persistence, respectively. A comparative study on the nutrient accumulation and biological cycles of the pure Moso bamboo forests, mixed bamboo and broad-leaved tree forests, and mixed bamboo and coniferous forests in northern Fujian Province, China shows that the mixed forests perform better in nutrient restitution than the pure bamboo forests. Intensive management will result in a significant reduction in total organic carbon, water-soluble organic carbon, microbial biomass carbon, and mineralizable carbon in soil [35]. And reusing chemical fertilizer itself is a source of greenhouse gas. Therefore, while celebrating the carbon sequestration feature of forests, we should also pay attention to protecting their ecosystem and biodiversity, rather than growing more and more single-species plantation forests. Single-species plantation forests will result in declining forest biodiversity and weakened ecosystem. Large-scale afforestation may also affect water resources, leading to the loss of a large number of streams and serious soil salinization and acidification.

2.3.3.2 Case Study on Anji, China

Located in Huzhou City, Zhejiang Province, China, Anji Country is one of China’s Top Ten Bamboo Cites. It is between 119°14’ and 119°53’ E and between 30°23’ and 30°53’ N, with an area of 1,885.71 km². It had a registered population of 470,700 in 2018. The area of mountains, hills, valleys, and plains in the county accounts for 11.5%, 50%, 13.1%, and 25.4% of the total area, respectively. With a sub-tropical monsoon climate, it enjoys mild weather and sufficient sunshine and rainfall, suitable for growing trees and crops. The county boasts a forest coverage rate as high as 70.2%.

In four decades from 1978 to 2017, the area of bamboo forests in Anji increased from 54,822 to 72,400 ha, an increase of 32%, while the bamboo culm production improved by 221% as a result of the increase in unit area yield brought about by intensive management. During the period, the number of bamboo processing enterprises in the county increased from 30 to 1,300 [6].

The bamboo industry in Anji has experienced five stages of development:

(1)
Stage 1 from the 1970s to the 1980s: The quantity and quality of bamboo resources were improved to develop the traditional bamboo industry. At this stage, demonstration forests with a high yield of bamboo stalks and bamboo shoots were planted; low-yield bamboo forests were restored; bamboo was mainly used to produce handicrafts and construction materials.
(2)
Stage 2 from the late 1980s to 2000: Bamboo processing machinery was introduced, which significantly improved the bamboo processing capacity and jobs. At the same time, bamboo forests began to be managed in a scientific manner. At this stage, the number of bamboo enterprises increased from 178 in 1988 to 1,620 in 1998. The industry developed a complete industrial chain from micro-sized companies and family workshops to small, medium, and large-sized enterprises; established demonstration bases of high-yield bamboo forests; developed bamboo product markets and exported a large number of bamboo products; set up a system of household contract-based management lasting for 30 years, and had 97% of bamboo forests being contracted.
(3)
Stage 3 from the late 1990s to 2009: Affected by relevant strategies and policies, the ecological economy was developed to maintain the comprehensive development of the bamboo industry. Ecology was given the same priority as the economy; 55% of bamboo forests were used for public water and soil control and ecological benefits; the development of ecological and cultural bamboo products began; most local bamboo processing enterprises were modernized; about 3,000 types of bamboo products in 9 series were produced.
(4)
Stage 4 from 2010 to 2015: The bamboo industry was shifted from the production sector to the comprehensive sector to coordinate the ecological economy and cultural industries. Anji built a prosperous society, thanks to the development of the bamboo industry. In 2015, its total output value of the bamboo industry reached RMB 21 billion (USD 3.23 billion), GDP per capita RMB 66,739 (USD 10,593), and farmers’ disposable income per capita RMB 23,610 (USD 4,300), bridging the gap between the urban and rural areas. However, the rise of other industries caused a reduction in the economic contribution of the bamboo industry. In addition, as the bamboo forest managers aged and the government exerted pressure on environmental production, farmers were losing interest in bamboo forest management, which ultimately led to an increase in costs of processing the harvested bamboo.
(5)
Stage 5 starting from 2015: Bamboo forests have been explored for multiple uses to coordinate the primary, secondary, and tertiary industries for mutual promotion. The management of large-scale bamboo forests have been strengthened; bamboo farmers have been encouraged to join cooperatives as shareholders; the government has built industrial development zones to promote the development of innovative, high-value, and high-tech bamboo products; the improved local ecosystem and landscape have been promoting recreational and cultural products as new drivers of growth in the bamboo industry in Anji; bamboo forests have been used as carbon sinks to boost carbon trading; value-added models involving bamboo and agriculture (bamboo+animals, bamboo+medicinal plants, bamboo+edible mushrooms, etc.) have been developed to improve the unit output value of bamboo forests; bamboo-based cultural industries, such as bamboo-based film and television bases, theme parks, museums, and craft design centers have been developed.

At present, the bamboo industry is one of the pillar industries in Anji County. By efficiently using the resources, Anji produces 18% of the total bamboo products with 1.8% of the total bamboo forest area in China. Regarding the primary sector, in 2017, Anji had 57,333 ha of Moso bamboo forests and 14,666 ha of forests of other small- and medium-sized bamboo species. It produced 30 million Moso bamboo culms, 70,000 tons of small- and medium-sized bamboo, 60,000 tons of bamboo shoots, and 60,000 tons of by-products such as bamboo branches, leaves, and tips. Regarding the secondary sector, in 2017, its output value of processed bamboo culms and bamboo shoots was RMB 13.8 billion. There were 3,000 kinds of processed bamboo products including bamboo boards, bamboo mats/bamboo curtains, food, beverage, handicrafts, textiles, and biochemical reagents. More than 40 companies were specialized in processing and utilizing bamboo waste, generating an annual output value of RMB 1 billion. Regarding the tertiary sector, in 2017, the county welcomed a total of 14.95 million tourists (32.5 times the number of local residents), who brought revenues as high as RMB 6.5 billion. There were more than 800 homestay hotels run by farmers providing 20,000 jobs and 10,000 beds, which generated an annual income of over RMB 500,000 for these families (Fig. 2.21).

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School of Architecture & State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, China
Zujian Huang

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Annex Tables

See Table 2.5.

Table 2.5 International trade volume of countries in Asia-Pacific Bamboo Area

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Huang, Z. (2021). Element Analysis of Bamboo Construction-Related Resource. In: Resource-Driven Sustainable Bamboo Construction in Asia-Pacific Bamboo Areas. Green Energy and Technology. Springer, Cham. https://doi.org/10.1007/978-3-030-73535-7_2

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Element Analysis of Bamboo Construction-Related Resource

Abstract

2.1 Bamboo Forest Resource

2.1.1 General Distribution

2.1.2 Main Bamboo Producing Countries

2.1.2.1 East Asia

2.1.3 South Asia

2.1.3.1 Southeast Asia

2.1.4 International Trade

2.2 Industrial Utilization and Processing Technology of Bamboo

2.2.1 “Utilization of Whole Bamboo”

2.2.2 Bamboo-Based Panel Production and Product System

2.2.3 Bamboo Damage and Preservative Treatment Technology

2.2.3.1 Damage Types

2.2.3.1.1 Abiotic Factors

2.2.3.1.2 Biotic Factors

2.2.3.2 Protection Treatment

2.2.4 End Utilization Technology

2.3 Economic, Social, and Environmental Impacts of Bamboo Industry

2.3.1 Climate Challenge and Bamboo Forests as Carbon Sinks

2.3.1.1 Carbon Sequestration and Carbon Reduction Mechanisms by Bamboo Forests and Bamboo Products

2.3.1.2 Afforestation and Bamboo Forest Management Carbon Projects

2.3.1.3 Voluntary Carbon Credits and Cases in China

2.3.1.4 Development and Use of Low-Carbon Products

2.3.2 Land Resources and Ecological Restoration

2.3.3 Economic and Social Impacts of Bamboo Industry

2.3.3.1 Bamboo Industry in China

2.3.3.2 Case Study on Anji, China

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