The construction industry, a significant contributor to global CO₂ emissions, has increasingly turned to wood as a renewable alternative in response to the recommendations of the Kyoto Protocol. However, despite advancements in timber technology and a growing demand for wood, the pace of reforestation has not matched up with consumption rates, risking future raw material shortages. This brief review explores the challenges and opportunities associated with the use of tropical wood in construction, emphasizing the need for sustainable management practices and diversified plantation strategies. We highlight the environmental risks of monoculture forestry and advocate for mixed-species plantations, which enhance CO₂ absorption and ecosystem resilience. The review focuses on Brazil's tropical forests, particularly the Amazon, emphasizing the importance of developing new forest products and restoring degraded lands to combat deforestation. Ultimately, leveraging the potential of tropical wood not only contributes to climate change mitigation strategies but also promotes forest restoration, linking environmental health with global sustainability efforts.

Keywords: reforestation, timber construction, native species, climate change mitigation

Spurred by the Kyoto Protocol,¹ the construction industry, responsible for around 40% of CO₂ emissions, embraced the recommendations for the widespread use of wood as a renewable and viable alternative for the sustainable maintenance of this activity. Several technologies were developed, and industrialised products made large-scale construction feasible in terms of area and height. Gains in manufacturing and assembly speed have also encouraged recalcitrant entrepreneurs averse to high risk to invest in these technologies, even as a marketing tool associated with environmental causes. However, the main recommendation of the Intergovernmental Panel on Climate Change (IPCC) was to emphasize planting and restoring vegetation cover to mitigate the impacts of such changes through afforestation and reforestation, along with other land management practices, which were valuable tools for reducing greenhouse gas emissions. The protocol encouraged countries to incorporate activities related to land use, land change and forestry (LULUCF) into their emission reduction strategies.

Although there has been effective growth, the speed and form of this reforestation have not kept pace with the expected increase in wood consumption used by construction, posing a real risk of raw material shortages in the next twenty years, according to a World Bank bulletin (World Bank Forest Action Plan FY16-20). The causes are clear: low utilisation of logs for producing highly industrialised products, the limited number of species suitable for these technologies, the slow growth cycle of temperate and boreal forests, and intense competition from the pulp and paper industry's commodity market.

For the past ten years, primary forest loss rates have remained high or increased again in most Amazonian countries, as Global Forest Watch and official data have pointed out (Tropical Primary Forest Loss Worsened in 2022, Despite International Commitments to End Deforestation, 27 June 2023).

The perspective of raw material scarcity would be the focus of this discussion, which is the proposal of alternative timber products that better use raw materials in any technology. Monoculture plantations have shown alarming environmental risks such as soil depletion, pests and threats arising from climate change in the form of above-average winds and less resistant trees, not to mention the poverty of redundant fauna and flora. Some studies also point to significant gains in CO2 absorption through mixed plantations and undergrowth, an observation that is valid for any biome studied globally.

Another fundamental issue is the development of technologies focused on low-density temperate species, excluding the enormous diversity present in tropical forests. All products, tools, adhesives and manufacturing systems have been developed in European countries, excluding the great potential offered by the numerous medium- and low-density species in tropical forests. Deforestation in these forests, partly illegal, is caused by land grabbing and the expansion of pastures, with illegal timber being only a by-product of this activity, which focuses on the densest and most commercially valuable species, which are not very suitable for industrial use in structures.

This review considers the experience in Brazil's tropical forests, especially the Amazon, and species from certified sustainable management. As this region is the global hotspot regarding deforestation and reforestation, we must concentrate our efforts on promote regulation in the region. This includes developing new forest products and recovering degraded areas with a mix of species and diverse economic interests that ensure their survival and those who depend on them. Large areas and patches of deforested land should be recovered and maintained. However, vast areas in the Pan-Amazon region (Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname and French Guiana) can recover and face the same endemic problems as the region.

Given the urgency of climate change mitigation and adaptation agendas, wood has joined the list of so-called New Building Materials, although its use in construction dates back thousands of years. Reviving the use of wood in structures and significant construction elements is an important step towards securing large volumes of carbon sequestered by trees. Considering that the concrete and steel industries are carbon-intensive, it will be difficult for the construction industry to reduce or eliminate its emissions without the widespread use of wood.

 The positive impacts of using wood go far beyond climate, as it is linked to forest restoration. In this field, the benefits are numerous, starting with land valuation and other ecosystem services Proper land management can not only recover degraded areas but also take advantage of underutilised areas and ensure the supply of clean water and soil stability.

In addition, a restored forest generates carbon and biodiversity credits and can even evolve into an agroforest, producing products such as high-value-added wood, fruits, oils, fibers, resins, and nuts. 

The diversity intrinsic to agroforestry systems is an advantage, as production cycles are complementary and there is synergy between crops. The more diverse the activity of an agroforestry system, the greater the risk diversification, resilience, and potential for gains in multiple markets over time.

For civil construction, the potential volume of wood from productive forests designed to remain standing permanently is comprehensive, with agroforestry systems and products integrated systemically throughout the construction chain. No large-scale research focused on this chain can be integrated into large-scale projects, and this industry largely overlooks Amazon.

In the forestry sector, there are great opportunities to develop inclusive processes associated with local cultures, generating the knowledge exchange necessary to increase efficiency. This opens opportunities throughout the wood product chain, as Brazil has a unique geographical condition in terms of size and diversity to promote these changes globally. 

Some objectives to stimulate sustainable timber production with a focus on construction can be addressed immediately:

1. Assess the primary industrial uses of less commercialised species in terms of availability of technological information, wood properties, silvicultural data, commonly used industrial production technologies, areas of natural occurrence and cultivation, potential uses in different harvest periods and potential uses in different industrial products.
2. Identify the main consumer markets for these less commercialised species.
3. Map opportunities for the use and trade of species, classified into short-, medium- and long-term markets;
4. Develop products and technologies from existing species already under certified sustainable management to advise reforestation strategies.

These are minimum conditions for large-scale industry development, since Amazonian wood has a very defined market with slight variation in end-use due to consumer demands. For instance, in the city of São Paulo, as in the rest of Brazil, the consumption of Amazonian wood in vertical construction is still significant. In 2001, for a built area of approximately 6 million square metres in São Paulo, approximately 216,000 cubic metres of sawn wood (equivalent to 0.6 million cubic metres in logs) originating from the Amazon were consumed. Of this total, 80% was disposable wood (formwork and scaffolding) and only 20% was processed products (flooring, window frames and furniture).²

Data from IMAZON² show the primary uses of sawn wood in Brazil, without distinguishing between wood from planted forests or native forests (Figure 1). 

Figure 1 Proportion of Amazonian sawn wood usage categories in Brazil.

Source: Imazon, 2013.

The IBGE³ details the quantities of wood from different sources, as shown in Figure 2. Less native wood is produced for industry from natural forests than from planted forests, suggesting that there is great potential for market development in this segment.

Figure 2 Quantity of wood by forest type, usage and species commercialized in Brazil, in 2016.

Source: PEVS/IBGE (2015) adapted SFB.

The engineered wood construction industry – referring to products made by aggregating small wood pieces into large structural components – primarily uses light woods with densities between 350 kg/m3 and 600 kg/m³. These woods typically originate from monocultures of conifers and hardwoods (such as pine and eucalyptus) cultivated over extensive areas primarily for the pulp and paper or firewood industries. Only a small portion of this lumber is used for sawing, and an even smaller fraction, consisting of logs over than 45 cm in diameter, is suitable for producing large, engineered wood products, as Glued Laminated Timber (GLT), Cross Laminated Timber (CLT) or Laminated Veneer Lumber (LVL). While these products store large amounts of CO₂, they have low utilisation of the industrial section of the log (the one with the lowest taper) at around only 25%, as shown in Figure 3. Added to this are considerable carbon emissions from processing, which include beneficiation, transport, kiln drying, selection and packaging, with specific characteristics for this market. The rest of the tree is relegated to low-value-added uses, since the ideal cut for industrialised products reduces its use in other segments.

Figure 3 Trunk utilisation of different engineered products (GLT, CLT and LVL, see text for more details).

Source: Author.

Industrialised wood products for construction, which use exotic species such as pine and eucalyptus, face competition from other products whose markets are consolidated and growing exponentially with new products added from the inclusion of other use categories, as shown in the graph below (Figure 4). The possibility of construction industry growth based on wood products depends on including other species and products based on trees that do not have a defined market and low added value, which includes many species currently present in tropical forests.

Figure 4 Industrialised products according to wood properties.

Source: Based and expanded from “The processing chain of engineered timber products”, in “The Wood from the Trees: The Use of Timber in Construction” (2017 P.H. Fleming.

This identification process begins with the design of archetypes that meet the above conditions. Their characteristics allow the selection of species to be investigated in objective tests for different products and uses with low processing emissions and a high degree of utilisation. 

The introduction of archetypes with different densities, cycles, and characteristics opens up great opportunities for combining species in the same product in varying proportions depending on each species' greater profitability (Figures 5–7).

Figure 5 Low-density archetype considering wood density of the species and related products.

Source: Núcleo da Madeira (2023).

Figure 6 Medium density archetype considering wood density of the species and related products.

Source: Núcleo da Madeira (2023).

Figure 7 High density archetype considering wood density of the species and related products.

Source: Núcleo da Madeira (2023).

For engineered or massive products, this opens markets currently dominated by low-density species, which in Brazil are mostly exotic. Currently limited research focused on the use of low and medium-wood density native species, and few projects combine different species in the same structural product. With the introduction of new structural laminates such as laminated veneer lumber (LVL), medium-density native woods can be incorporated as a stiffening element in components without necessarily adding weight, since the model reduces component dimensions.^4,5

The gaps in the information available on native species create difficulties in their analysis and opportunities for future studies and exploration by the timber sector.

The species under study have potential applications across various timber sectors. Therefore, it is essential to design a product chain that facilitates the final selection of species suitable for planting. This process should consider the technologies needed to process different types of wood for each product. Additionally, it is necessary to prioritize species that are not only of interest for planting in the carbon credit market but also contribute to the reforestation of degraded areas.

Outlook

To avoid an 'environmental blackout' and to promote the mitigation of deforestation, it will be necessary a transition from using legally and sustainably harvested wood to wood from progressively planted native forests, which directly contributes to the expansion of the native wood market.

To prevent an “environmental blackout” and address the issue of deforestation, we need to shift from using legally and sustainably harvested wood to sourcing wood from newly planted native forests. This transition will help promote the growth of the native wood market.

Every pioneering process has margins of risk that are not fully mapped, and nature has unpredictable responses incompatible with the industrial culture established by the market. A broad dissemination programme is needed to change counterintuitive paradigms in the market's view. That said, it is essential to develop a market for less-known native species, thereby increasing the diversity of products in the timber sector and reducing pressure on species currently at risk of extinction due to overexploitation because of their known economic potential.

It is essential to encourage behavioral changes in recognizing and using wood as a modern and technological material. This shift could provide Brazil with a significant competitive advantage in the future. Another critical issue is the cultivation of native tree species, particularly those that are underutilised but have potential applications in construction, considering their properties and possible uses.

Incentive programs for sustainable forest production are crucial in reducing illegality in the timber economy, which poses a significant challenge to contemporary industry. It is essential to form high-yield forests and develop models for multiple-use forests that cater to various biomes and cycles to establish a sustainable forest economy.

None.

None.

There is no conflict of interest.

1. Kyoto protocol to the United Nations framework convention on climate change. FCCC/CP/1997/L.7/Add.1. 2025. 
2. IMAZON – Instituto do Homem e Meio Ambiente da Amazonia. Acertando o Alvo 2: consumo de madeira amazônica e certificação florestal no estado de São Paulo. 2013.
3. Instituto Brasileiro De Geografia Estatística (IBGE). PEVS - Produção da extração vegetal e da silvicultura. 2016.
4. Instituto Brasileiro De Geografia Estatística (IBGE). SCNT - Sistema de Contas Nacionais Trimestrais – 1º trimestre de 2023.
5. Warner E, Cook-Patton SC, Lewis OT, et al. Young mixed planted forests store more carbon than monocultures—a meta-analysis. Front For Glob Change. 2023;6:1226514.