Advancing Sustainable Timber Protection: A Comparative Study of International Wood Preservation Regulations and Chile’s Framework Under Environmental, Social, and Governance and Sustainable Development Goal Perspectives

Abstract

Wood is an essential construction material because of its renewable nature, versatility, and ability to store carbon, which aids in climate change mitigation. However, its biodegradability requires preservation treatments to prolong its service life and improve its durability. This study compares international wood preservation regulations with the Chilean framework and evaluates their alignment with Environmental, Social, and Governance (ESG) criteria and the Sustainable Development Goals (SDGs). The findings reveal a global trend focused on reducing hazardous preservatives like chromated copper arsenate (CCA) while promoting environmentally friendly alternatives. The discussion emphasizes the need for strategic regulatory updates and investment in sustainable wood protection technologies. These efforts are essential for ensuring long-term structural performance, resource efficiency, and market competitiveness.

1. Introduction

Wood has been a vital resource in construction for millennia and remains the only renewable building material at an industrial scale. Its lightweight nature, high strength-to-weight ratio, and excellent thermal insulation properties make it an exceptional choice for sustainable building practices. Furthermore, wood holds significant economic value globally. Between 1990 and 2019, the international trade in wood products rose by 143%, amounting to USD 244 billion [1].

According to an estimation by [2], the carbon storage capacity of newly constructed buildings in Europe between 2020 and 2040 is directly influenced by both the quantity and volume of wood-based components incorporated into these structures. Beyond its structural role, wood also offers significant benefits for indoor environments, contributing to physiological comfort and mental well-being [3,4,5], and it is part of historical buildings [6]. Additionally, within the framework of a developing circular economy, wood stands out as a zero-waste material, as it can be repurposed for energy generation once its primary service life as a construction product has concluded [7].

Moreover, it is reasonable to recognize that the general public often lacks familiarity with the specific terminology and classifications associated with wood construction. A study by [8] concluded that it is essential to promote wood construction by emphasizing its technical and economic advantages rather than solely its societal benefits. Simultaneously, addressing existing societal barriers should be a priority, alongside developing standardized and harmonized policies. The authors also highlight the importance of generating region-specific knowledge, providing valuable insights for policymakers in revising and adapting building codes within their respective countries.

Hurmekoski [9] suggests that the expansion of multistory wood construction is most likely to occur in the Nordic countries and certain regions of Central Europe, with a strong societal commitment to utilizing domestic forest resources. Although interest in this approach has increased notably over the past five years, the progress of large-scale wood construction markets remains hindered by the inertia and established practices of designers and the construction industry, which continue to favor conventional materials and methods. A survey of stakeholders, manufacturers, and end-users was carried out in six European countries and Chile, indicating that one-third of the participants demonstrated preconceived or misinformed perceptions regarding the performance of wooden buildings, particularly concerning their fire resistance and moisture-related behavior [8]. Furthermore, the wood industry must prove its technical and economic advantages to address prejudices regarding durability and performance, thereby advancing sustainable construction practices and contributing effectively to the bioeconomy.

The durability and protection of wood are fundamental to ensuring its long-term performance, especially in construction and infrastructure applications. As a biodegradable material, wood is inherently vulnerable to deterioration caused by biological agents—including fungi, insects, and bacteria—and environmental stressors such as moisture, ultraviolet radiation, and temperature fluctuations. In response to these challenges, the formulation and application of wood preservatives have undergone significant advancements in recent decades [6,10,11,12]. Wood preservation using chemical wood preservatives extends the service life compared to untreated wood [13], lowering atmospheric carbon dioxide by retaining the accumulated carbon. Nevertheless, growing environmental awareness and the pursuit of sustainable development have prompted regulatory agencies to restrict certain chemical preservatives, particularly those containing heavy metals and hazardous substances. A prominent example is pentachlorophenol (PCP), a synthetic organochlorine compound that has been widely employed as a pesticide and wood preservative against wood-decaying fungi. This compound presents considerable environmental and health risks due to its persistence, potential for bioaccumulation, and toxicity. As a result of these dangers, pentachlorophenol was added to the Stockholm Convention’s list of persistent organic pollutants and phased out of industrial use in 2023 [14].

The Sustainable Development Goals (SDGs), established and adopted in 2015, are designed to serve as a framework for countries. They guide the implementation of public policies and budgeting tools for planning, monitoring, and evaluating progress toward sustainable and inclusive development that is environmentally responsible. In this context, developing and using environmentally safe wood preservatives is crucial for extending the service life of timber structures while reducing resource depletion and environmental contamination. These advancements can directly contribute to achieving SDGs 9, 11, 12, and 13.

In the current investment landscape, there is an increasing emphasis on incorporating environmental, social, and corporate governance criteria, commonly known as ESG. The “E” stands for environmental factors; the “S” represents social criteria that affect workers, consumers, and communities; and the “G” addresses governance and corporate culture, examining aspects such as accountability, transparency, gender pay disparities, and fiscal responsibility. The emergence of sustainable investment in financial markets highlights the importance of considering not only profitability but also the long-term social and environmental impacts of investments. This shift has led to Sustainable Finance, where commitment to societal and environmental responsibilities is integrated into investment decisions [15]. Within this context, the wood preservation sector offers a strategic opportunity to align with ESG principles [15,16,17], presenting more attractive and sustainable investment prospects. The transition to more environmentally friendly preservatives carries significant economic, social, and environmental implications. Selecting safer chemical or bio-based products is essential for implementing practices that ensure the health and safety of workers and society—central aspects of social responsibility.

The challenge lies in the gap between chemical preservatives, which must provide technical evidence demonstrating their efficacy, and bio-based, environmentally friendly products, which may lose effectiveness in the short term. This lack of reliable protection can lead to structural degradation, chemical or biological leaching, decreased effectiveness, and adverse environmental impacts [18,19,20]. How can we achieve efficiency and sustainability with protection measures that lack durability and will not sufficiently protect the wood? It is important to recall that the primary objective of wood preservatives is to extend the service life of wood, thereby maximizing the benefit of the sequestered carbon. Using natural but insufficiently effective protection methods could increase CO₂ emissions if the wood’s lifespan is not sufficiently prolonged.

In 2020, Europe adopted the European Green Deal, a comprehensive set of policy initiatives to guide the European Union (EU) toward climate neutrality by 2050. This strategy is the foundation for transforming the EU into a fair and prosperous society supported by a modern and competitive economy. The EU Forest Strategy for 2030 is a key component of the European Green Deal, intending to reduce greenhouse gas (GHG) emissions by at least 55% by 2030. Among the proposed measures are the promotion of sustainable forest management, the provision of financial incentives to forest owners and managers to encourage environmentally responsible practices, and efforts to increase the size and biodiversity of forests, notably through the ambitious goal of planting 3 billion new trees by 2030 [21]. Similarly, Chile has set the goal of achieving carbon neutrality by 2050, with forest resources playing a key role in this objective. It is projected that at least 50% of CO₂ emissions will be offset through carbon sequestration by forest growth [22]. Additionally, the Chilean Ministry of Agriculture has recently introduced a long-term strategic policy for advancing the forestry sector. This initiative maximizes the country’s forestry potential, encompassing natural resources, industrial development, and strengthening technical and scientific expertise by 2035. A central aspect of this policy is to position wood as a primary construction material, aiming to increase its use in buildings from 18% in 2015 to 36% by 2035 [23].

Wood construction can be crucial in fostering sustainable and resilient cities if strategies are implemented to enhance its durability, efficiency, and minimal environmental impact. Worldwide, countries have established regulatory frameworks and technical standards to guide the selection and application of wood preservatives, aiming to balance effectiveness, human and environmental safety, and regulatory compliance. These frameworks differ based on national priorities, climate conditions, construction traditions, and market demands. Integrating sustainability principles into wood protection strategies has accelerated research and innovation toward safer, more environmentally benign alternatives.

In this context, it is essential to evaluate the practices of countries with well-established traditions in wood construction and compare them to national regulations, such as those in Chile. This comparative analysis would reveal regulatory gaps, identify areas for improvement, and uncover strategic opportunities for adopting safer and more sustainable wood protection technologies. The international search criteria prioritize environmentally efficient solutions for wood preservatives that Chile must implement to enhance effective wood protection in construction, especially regarding the associated risk classes.

This systematic bibliometric study examines the international regulatory landscape and technical approaches to wood preservation, specifically focusing on how these frameworks integrate environmental and sustainability considerations. Additionally, the regulatory context in Chile is analyzed in relation to international developments, particularly regarding the continued use of chromated copper arsenate (CCA) and the exploration of alternative preservation solutions. Furthermore, this research addresses the integration of ESG criteria within the wood impregnation industry, highlighting the urgency of developing more sustainable solutions.

2. Materials and Methods

Digital technical–scientific bibliographic material was used from Web of Science, Scopus, Nature Journals, Scielo, and Google Scholar, among other databases, including scientific articles, technical reports, books, manuals, theses, and dissertations from 2014 to 2024. The defined time frame confines the review to the most recent scientific publications, ensuring that the analysis remains focused on the latest advancements and prevailing trends in the field. This methodological approach prioritizes up-to-date information, providing insights that accurately reflect the most recent research findings and developments.

Technical, environmental, social, governance, and cost aspects were considered for the comparative sustainability analysis of preservatives. The objective was to document background information, application methodologies, sustainability evaluation, and new wood protection techniques in countries with a strong wood construction culture and their applicability in Chile.

The bibliographic review used keywords and descriptors in Spanish, English, and German to quantify and classify the types of wood preservatives and their application processes. The terms included Chemical wood preservatives, CCA, uCA, LOSP, Methods of applying wood preservatives, Wood protection systems for construction, Modified wood, Bio-based wood preservative, EPA, ECHA, ESG, Sustainability and efficient indicators for biocides, Sustainable assessment for wood preservatives, among others. These terms were entered into the search engines of scientific databases, considering that the research focused on wood preservatives, protection techniques, and stages (such as impregnation and physicochemical modification) for the protection of wood used in construction, as well as sustainability indicators and factors influencing efficacy. Boolean operators were used as a search method to combine and exclude two or more terms. The connecting words used were AND, OR, and NOT. The parameters and sustainability indicators reported by the authors for wood preservation were recorded. This aimed to identify the main restrictions countries imposed and investigate how they are being addressed and the methods being implemented.

3. Results and Discussion

3.1. Key Aspects in Wood Preservation

The bibliometric study encompassed key aspects relevant to timber construction in countries with significant experience in this field, including Germany, Canada, the United States, Japan, New Zealand, and Sweden. Additionally, Chile was included since this country has the potential to adopt and implement wood preservatives currently used in the reference nations due to its regulatory capabilities and commitment to sustainable development. The analysis presented in

Table 1. Analysis of key aspects in wood preservation in countries with established experience in timber construction.

Country	Germany
Main wood species	Picea abies (25%), Pinus sylvestris (22%), Fagus sylvatica (15%), Quercus robur (10%), and Larix decidua (3%) with a much smaller surface area [24].
Causes of biodegradation	Decomposition caused by fungi and attacks by Hylotrupes bajulus and wood-boring larvae. Subterranean termites are not a widespread problem, except for a localized occurrence in Hamburg [25].
Preservatives currently in use
Since 2017, wood preservatives containing chromium have been prohibited and replaced by copper-based organic alternatives (copper-quat, copper-azole, and copper-HDO) for vacuum-pressure treatments. Creosote is exclusively permitted for use on railroad ties, and there are currently no available treatments for marine applications. Over the past three decades, solvent-based products for construction timber, whether used indoors in protected environments, have been largely phased out. They have been replaced by water-based preservatives that include azoles, quaternary ammonium compounds (quats), carbamates, morpholine, and insecticides. These preservatives are primarily applied by immersion or through flow-coating/spraying methods. Temporary treatments are also applied by immersion or spraying and contain the same active substances, except insecticides [25].
Regulation
The Biocidal Products Regulation (BPR, Regulation (EU) 528/2012) regulates the marketing and use of biocidal products within the European Union. Germany plays a key role in the European wood preservative market, and this regulation aims to enhance the effectiveness of the biocidal products market while ensuring a high level of protection for both humans and the environment. Key industry players are organized under the “RAL Quality Association: Impregnated Timber Construction Elements.”
Standards for wood protection
Wood for construction in Germany and its protection are standardized by several regulations, including EN 15228:2009 Structural Timber—Wood Preservative for Structural Timber Treated Against Biological Attack [26]. The requirements for timber construction are outlined by the German standard DIN 68800. This standard aims to ensure that the wood used in construction is durable and resistant to biological attacks, developed by the German Institute for Standardization [27].
Country	Canada
Main wood species	Picea mariana (44.3%), Populus tremuloides (13.7%), Pinus contorta (11.7%), Picea glauca (8.3%), and Pinus banksiana (6.2%) [28].
Causes of biodegradation	Decomposition is the primary cause of biodegradation in Canada. There are also populations of subterranean termites in southern Ontario (Reticulitermes flavipes) and southern British Columbia (Reticulitermes hesperus). Marine borers are present in waters off the Atlantic and Pacific coasts [25].
Preservatives currently in use
There are five wood preservatives registered with the Pest Management Regulatory Agency (PMRA) for treating wood in residential uses: alkaline copper quaternary (ACQ), copper azole (CA), micronized copper azole (MCA), didecyldimethylammonium carbonate (DDAC), and disodium octaborate tetrahydrate (DOT or SBX) borates. In this country, the PMRA has developed a document focused on the treated wood industry. This document outlines the allowed uses for wood preservation in industrial applications, including chromate copper arsenate (CCA), creosote, pentachlorophenol, and copper and zinc ammoniacal arsenate (ACZA).
Regulatory
The wood preservative products are regulated by Pest Control Product Laws and must be registered with the Pest Management Regulatory Agency (PMRA) of Health Canada.
Standards for wood protection
The National Building Code of Canada (NBC 2020), published by the National Research Council of Canada (NRC), establishes requirements for the use of treated wood in residential buildings and small structures, aimed at protecting it from fungal decay, termite infestation, and other forms of deterioration. While the NBC itself is not mandatory, provinces and territories across Canada have adopted it as the framework for their building codes. The NBC 2020 specifies minimum standards for treated wood usage, which may be supplemented or modified by the specific building codes of each province or territory. The CSA 080 Series of Standards, referenced in the NBC, governs the manufacturing and application of wood preservatives. These standards specify which wood species require treatment, the allowable preservatives to use, and the necessary retention and penetration levels of the preservative in the wood to comply with the specified use category.
Country	United States
Main wood species	Predominantly southern pine, especially in the construction sector [25].
Causes of biodegradation	Decomposition is the leading cause of biodegradation [25].
Preservatives currently in use
The Environmental Protection Agency (EPA) has classified CCA, creosote, and pentachlorophenol as restricted-use products, prohibiting their application in residential settings, indoor uses, or any instances where they could contaminate drinking water or food [29]. In response to the growing demand for safer wood treatment options, several alternative wood preservatives have been introduced to the market. One notable example is propiconazole, a fungicide utilized in carpentry and structural applications; however, its use is restricted to above-ground applications, and it does not offer protection against insect damage. Other noteworthy preservatives included triadimefon (a fungicide) and acid copper chromate (ACC), which is exclusively registered for industrial and commercial use. Additionally, isothiazolinones are being adopted in carpentry and utility poles [29]. The chemical wood preservatives registered for residential wood treatment include ACQ, borates, copper azole, copper naphthenate, copper-HDO (Bis-(N-cyclohexylthiazolium-copper)), and Polymer Betaine. Among these, ACQ is currently the most widely used preservative for residential applications.Approximately 80% of wood usage is for residential purposes, with 10% allocated to utility poles and another 10% to railroad ties. The modification of wood via acetylation has achieved moderate success in housing, though it is limited to acetylated radiata pine imported from Europe. There was an attempt to produce acetylated Southern Pine locally, but unfortunately, it was unsuccessful [25].
Regulatory
The EPA is the federal agency responsible for approving, registering, labeling, and regulating the use of pesticides, including wood preservatives, setting standards for their safe and effective use (EPA, 2023).
Standards for wood protection
The American Wood Protection Association (AWPA) is the primary organization responsible for preparing standards regarding wood protection and is the leading technology transfer group in the field.
Country	Japan
Main wood species	Fifty percent of Japan’s forests consist of conifer species, with 20% being Japanese Cedar (Cryptomeria japonica) and 10% Japanese Cypress (Chamaecyparis obtusa). On the other hand, the country’s forests contain 44% broadleaf species, mainly including 10% Japanese Oak (Quercus spp.) and 4% Beech (Fagus crenata) [30].
Causes of biodegradation	Decomposition is the leading cause of biodegradation [25].
Preservatives currently in use
The preservatives authorized under the Japanese Industrial Standards K 1570 (2010) are ACQ-1, ACQ-2 (quaternary ammonium copper); CuAZ (copper azole compound); AAC-1, AAC-2 (quaternary ammonium compound); BAAC (boron, quaternary ammonium compound); SAAC (pyrethroid compound not quaternary ammonium); AZAAC (pyrethroid compound not quaternary ammonium azole ether); and AZNA (neonicotinoid compound of quaternary ammonium azole) as water-based preservatives; NCU-E (emulsified copper naphthenate); NZN-E (emulsified zinc naphthenate); VZN-E (emulsified zinc versaticate); and NCU-O, NCNU-O, NZN-O (metal salt compounds of naphthenic acid) as oil-based wood preservatives. Approximately 75% of the wood treated has been used for residential building materials. Due to the Water Pollution Prevention Law enacted in 1997 by the Government of Japan, many companies ceased the production of CCA-treated wood, switching to copper-based preservatives (copper azole and ACQ) and water-based preservatives (Boro-quat and Alkyl Ammonium Quat) [30].
Regulatory
The Japan Wood Preservation Association (JWPA) is responsible for approving and registering active substances and formulation data, efficacy data, usage instructions, and waste management for wood preservatives. The Housing and Wood Technology Center in Japan is responsible for registering Approved Quality (AQ) to obtain the JWPA certification later.
Standards for wood protection
The Japanese Industrial Standards (JIS) are a series of standards established by the Japanese Industrial Standards Committee (JISC) and published by the Japanese Standards Association. Regarding wood preservation, there are two primary JIS: JIS K 1570 “Wood Preservatives” and JIS K 1571 “Wood Preservatives—Performance Requirements and Test Methods to Determine Efficacy.” Both JIS standards are important for certifying wood preservatives and treated wood products. Additionally, there is the JIS A 9002 standard, “Treatment of Wood Products with Preservatives by Pressure Processes”, and the JIS A 9104 standard, “Wood Crosses Treated with Preservatives by Pressure Processes” [25].
Country	New Zealand
Main wood species	Pinus radiata D. Don [25].
Causes of biodegradation	Insects attack and decomposition risks [25].
Preservatives currently in use
ACQ and CuAZ have been registered and approved for use in New Zealand as alternatives to CCA. However, their higher cost limits their application primarily to situations with a reduced risk of decay for economic reasons. In recent years, there has been an increase in the use of Light Organic Solvent Preservatives (LOSPs) as an alternative to CCA. One significant advantage of LOSP is that it does not require additional drying post-treatment, which helps prevent dimensional changes in the timber during the preservation process. A key export market for LOSP-treated wood is Australia, where this treatment has been accepted for structural timber grades. Domestically, water-based azole treatments and LOSP are widely used for applications such as cladding. Currently, more than 90% of timber framing used in construction is treated with boron-based preservatives, encompassing both timber and engineered wood products (EWPs) [25].
Regulatory
The New Zealand Timber Preservation Council (NZTPC) is responsible for licensing timber treatment facilities throughout the country.
Standards for wood protection
The New Zealand Standard (NZS) 3640:2003, titled “Chemical Preservation of Round and Sawn Timber”, establishes the minimum requirements for wood preservative treatments. It also provides guidelines for determining protection levels against decay and insect damage based on six hazard classes defined within the standard. In addition, the standard NZS 3602:2003, “Timber and Wood-Based Products for Use in Building”, specifies the performance requirements for timber and wood-based products for specific construction applications. This ensures that these materials perform adequately over the expected lifespan of a building. This standard complements the New Zealand Building Code, specifically Clause B2—Durability, which outlines durability requirements for individual building components.
Country	Sweden
Main wood species	Pinus sylvestris (39.8%), Picea abies (38.8%), and Betula pubescens (13%) [31].
Causes of biodegradation	Descomposition and presence of Hylotrupes bajulus [25].
Preservatives currently in use
CCA-based preservatives have been withdrawn from the market, and the primary alternatives now available are copper-based organic preservatives, including copper-quat, copper-azole, and copper-HDO. LOSP formulations containing azoles are used on a limited scale for window joinery, employing a double-vacuum process. However, most window joinery is treated using a water-based flow-coat system that incorporates iodopropynyl butyl carbamate (IPBC) and azoles. Meanwhile, creosote continues to be utilized for utility poles and wooden railroad ties [25].
Regulatory
The Biocidal Products Regulation established by the European Chemicals Agency requires that all wood preservatives receive authorization from the Swedish Chemicals Agency (KEMI). This agency is responsible for the comprehensive evaluation and approval of active substances and formulations, ensuring their safe and effective application within Sweden [25].
Standards for wood protection
The Nordic Wood Preservation Council (NWPC) is an organization dedicated to collaborating with the wood protection industries across the Nordic region to enhance the competitiveness and sustainability of wood as a construction material. The Council has established the Wood Durability and Quality System (NTR), which provides comprehensive guidelines and recommendations to ensure the durability, quality, and reliability of treated wood. In the Nordic countries, approximately 90% of preservative-treated Pinus sylvestris is produced by treatment companies that are members of the NWPC’s certification and quality control program [25].
Country	Chile
Main wood species	Pinus radiata (98%) and Eucalyptus spp [32].
Causes of biodegradation	Several native fungi in Chile can cause decay in pine wood when exposed to moisture. Additionally, Pinus radiata is vulnerable to a combination of fungi and bacteria that result in blue stain, a defect that primarily affects the wood’s appearance rather than its mechanical properties. Termites represent the most significant threat to Pinus radiata, particularly in the central regions of Chile. Although five species of termites have been identified, only three are economically significant: Neotermes chilensis (Blanchard), Cryptotermes brevis (Walker), and Reticulitermes flavipes (Kollar), the latter being responsible for the most severe structural damage, leading to substantial economic losses.
Preservatives currently in use
ACQ, SBX, CA-B, CCA, Creosote, LOSP, MCAz, μCA-C.
Regulatory
The Agricultural and Livestock Service (Servicio Agrícola y Ganadero, SAG) is the authority in Chile responsible for regulating and authorizing active substances in wood preservatives.
Standards for wood protection
The wood protection standards in Chile encompass NCh789/1:2023, which classifies wood based on its natural durability. Additionally, NCh 819:2019 addresses wood preservation by categorizing wood according to service risk levels and sampling criteria. For instance, if wood is classified as “Not durable” for service risk classes 3, 4, or 5 and is intended for construction use, the Chilean General Ordinance of Urban Planning and Construction (OGUC) mandates the treatment of such wood with preservatives, as outlined in Article 5.6.8, which incorporates NCh 819:2019. This requirement is applicable when manufacturing engineered wood products, such as cross-laminated timber (CLT). Furthermore, the ordinance offers recommendations for termite prevention. The current distribution of preservative usage is as follows: 73% is attributed to CCA, 23% to LOSP, and 4% to µCA-C. These data encompass both domestic and export markets.

focused on the identification of the predominant wood species used in each country, the primary causes of biodegradation affecting wood in service, the chemical preservatives currently employed and their methods of application, the regulatory authorities responsible for overseeing active substances, and the standards governing wood protection. This review specifically addressed the biotic protection of wood; abiotic protection, while equally important, was excluded to maintain a focused study scope.

Wood protection is essential to extend its service life and enhance its resistance against various destructive agents, as previously mentioned. This study did not assess the performance of individual wood preservatives under specific climatic conditions. However, it is essential to acknowledge that environmental factors such as humidity, temperature, and precipitation play a significant role in wood degradation processes. These factors influence abiotic deterioration, such as cracking and erosion, and the activity of biotic agents like fungi and insects. In regulatory practices, countries like Chile address these concerns indirectly by defining risk classes based on the expected exposure conditions for wood products. As a result, the selection of preservatives is guided by risk class rather than specific climate parameters. Nonetheless, recognizing that climatic variability underpins risk classification frameworks offers a deeper understanding of wood protection strategies. Wood preservatives are essential for safeguarding against the adverse effects of climate change and for extending the maintenance intervals of wood products [11]. To improve the durability of wood against biological organisms, several treatment methods have been developed, and the reader is encouraged to consult specific publications, such as the work published by [33,34], for a more detailed discussion. One such method is modification by impregnation, which involves introducing one or more chemical compounds into the wood cell walls. These compounds react to form stable structures that block access to hydroxyl groups, thereby reducing the wood’s hygroscopicity and improving its dimensional stability and resistance to decay. The main impregnation treatments currently available in the market are acetylation and furfurylation. The acetylation involves the reaction of acetic anhydride with wood, resulting in the esterification of hydroxyl groups; the wood cell wall is saturated with acetic anhydride, replacing the free hydroxyl groups of the cellulose and hemicellulose macromolecules. This treatment increases dimensional stability and biological resistance. The acetylation process is highly efficient, as it operates without additional solvents, utilizing pure acetic anhydride and enabling complete recycling of unreacted chemicals. Although the reaction generates significant amounts of acetic acid as a stoichiometric by-product, acetylation remains a notable example of a sustainable wood modification technique [35,36]. Acetylated wood is already produced on an industrial scale and is commercially available under trademarks such as Accoya [37]. Additionally, related esterification processes that employ bio-based compounds, including citric acid or itaconic acid, are considered even more environmentally friendly alternatives [38,39,40]. Furfurylation treatment involves impregnation with furfuryl alcohol, which reduces the equilibrium moisture content and increases the dimensional stability of the wood, resulting in a proportional increase in the mass of the wood. It is considered an environmentally friendly treatment, which consists of catalytic polymerization of furfuryl alcohol in wood. Currently, its production is carried out under the name Kebony [37]. Another method consists of thermal modification. Thermally modified wood is produced by subjecting it to high temperatures (160–215 °C) in an oxygen-free atmosphere. This process activates the physical–chemical components present in the cell walls, improving the wood’s resistance to biodegradation [41,42,43]. In Finland, approximately 12 million cubic meters of sawn timber were produced in 2018, with 80% allocated for construction. The ThermoWood process produces two types of products: Thermo-S and Thermo-D, each tailored to specific properties and intended applications of the final product [11].

Vacuum-pressure treatment, commonly applied to pine wood, allows for the impregnation of the sapwood with preservatives, while the heartwood only receives superficial penetration. This treatment creates notable durability, although constant concerns about the environmental impact and human health risks associated with chemical products have restricted some preservatives, particularly those based on chromium, copper, and arsenic (CCA). This is the case in the United States and several European countries, as indicated in Table 1. Global efforts are being made to develop alternative, naturally derived preservatives with minimal to no toxicity [10]. The Swedish wood preservation industry has evolved since the gradual phase-out of CCA in the mid-1990s. Organic copper-based wood preservatives, such as copper-quat, copper-azole, and copper-HDO, have replaced CCA with water-based products now serving as the most prevalent treatment method. In numerous countries, wood preservation primarily focuses on class 4 applications. This means treatments are intended for wood that comes into direct contact with the ground, similar to how a dead tree interacts with the forest soil. Consequently, the evaluation of the biocide toxicity threshold often remains grounded in this type of exposure scenario. Field tests involving ground contact, along with a zero-risk approach, continue using highly toxic preservatives such as creosote, CCA, and PCP. However, creosote is still used for utility poles and railroad ties [25]. The most common wood preservation techniques used in Nordic countries are the Bethell and Rüping processes, mainly employed for creosote impregnation. As was presented in Table 1, chemical compounds and their uses are regulated in different countries, which establishes requirements for biocides based on technically equivalent active substances. Each country defines specific technical requirements for evaluating active substances submitted to its competent authority. Consequently, approval in one country does not ensure authorization for use in another. As such, new developments must undergo the approval processes, which involve conducting the necessary studies following internationally recognized and current protocols. These protocols included, but are not limited to, organizations such as CICAP (Center for Research and Training in Public Administration), ASTM (American Society for Testing and Materials), ISO (International Organization for Standardization), OECD (Organization for Economic Cooperation and Development), EPA OCSPP (Environmental Protection Agency Office of Chemical Safety and Pollution Prevention), and EEC (European Economic Community, now referred to as the European Union, EU).

Based on the data presented in Table 1, a comparative

Table 2. Biocides products used for wood protection in various countries.

Country	Biocides	Coincident with Chile	Used Abroad and Not Found in Chile 1
Germany	ACQ, CA Copper-HDO and Creosote (only wooden railroad ties)	ACQ, CA, Creosote	Copper-HDO
Canada	Residential use: ACQ, CA, MCA, DDAC, SBX Industrial use: Creosote, Pentachlorophenol, ACZA, CCA	ACQ, CA, MCA, SBX, Creosote, CCA.	DDAC, Pentachlorophenol, ACZA.
United States	Residential use: ACQ, DOT, CA, Copper naphthenate, Copper-HDO, Polymeric betaine. Industrial use: Triadimefon, CCA, acetylated wood	ACQ, CA, CCA	DOT, Copper naph-thenate, Copper-HDO, Polymeric betaine, Triadimefon, Acetylated wood
Japan	ACQ, Boron + AZAAC, AZNA, Boro-quat y Quat Alkyl Ammonium.	ACQ	Boron + AZAAC, AZNA, Boro-quat y Quat AlkylAmmonium
New Zealand	ACQ, CA, CCA y LOSP.	ACQ, CA, CCA y LOSP.
Sweden	ACQ, CA, Copper-HDO, acetylated wood, furfurylation, thermal treatment	ACQ, CA, thermal treatment	Copper-HDO, furfurylation, acetylated wood
Chile	ACQ, SBX, CA-B, CCA, Creosote, LOSP, MCAz, μCA-C.	Under established regulations, each country identifies the most appropriate wood species based on designated use risk classes for different applications. This selection process is complemented by the choice of suitable preservatives tailored to meet specific protection requirements	In Chile, the standard that specifies the appropriate type of preservative for each risk classification is NCh 819:2019. This standard is associated with the natural durability of several exotic and native wood species, and it mandates the treatment of radiata pine because of its low durability in structural construction applications.

¹ The selection of preservatives is crucial, but various other factors also impact service life. This section highlights that some countries continue to utilize the most effective preservatives for high-risk applications. They prioritize efficacy over the shift towards less polluting alternatives, emphasizing proper usage and maintenance practices.

was created to highlight the differences among the biocides used in various countries. The comparative analysis of international wood protection practices reveals a global trend toward reducing or eliminating hazardous wood preservatives, particularly those containing chromium, copper, and arsenic (CCA). Countries like Germany and Sweden have already implemented complete bans on CCA for construction purposes. In contrast, others, including the United States and Canada, have opted for partial restrictions, allowing their use exclusively in specific industrial or exterior applications. Robust regulatory frameworks support these decisions, emphasizing the significance of environmental safety, protection of human health, and long-term sustainability. Notably, these countries implement preservative treatments for wood within high-risk categories. This strategy ensures adequate performance, as depending solely on design-based protection is insufficient. Additionally, the long-term effectiveness of chemical and physical modification treatments remains under evaluation.

In Chile, in contrast to the countries referenced in Table 1 and Table 2, the use of CCA (chromated copper arsenate) is still permitted for wood products in construction. Although alternative preservatives have already been registered and are available on the market, their commercial application remains limited. The wood impregnation process using CCA presents several advantages, primarily due to its established nature and the associated economies of scale and market accessibility. A supplier of chemical preservatives in Chile has indicated that the cost of protecting one cubic meter of wood with MCA could be as much as 50% higher than that of CCA. Therefore, a clear strategy for using CCA should be established. Based on the approaches adopted by other countries, one possibility would be to restrict its use in residential construction for interior applications, as practiced in the United States and Canada, limiting its use strictly to specific exterior and industrial applications before considering a complete ban, as has been the case in Germany and Sweden. Alternatively, Chile could follow New Zealand’s approach, where, due to the high cost of CCA alternatives, the use of CCA continues to be allowed in situations involving high decay risk. At the outset of this study, it is clear that the wood preservation industry must prioritize replacing hazardous products with safer, environmentally friendly alternatives. This shift is essential, provided these alternatives are technically feasible and economically viable.

An important consideration in the use of wood is its natural durability, which refers to the inherent resistance of wood to degradation by wood-destroying organisms. Biological durability is critical when selecting wood or wood-based products for specific applications. Alongside considerations such as climate, product design, and service conditions, natural durability plays a significant role in accurately predicting the service life of wood products. The European Standard EN 350:2016 categorizes end uses into various risk classes. Class 1 refers to dry wood used in interior construction, while Class 2 applies to wood fully protected from the weather but occasionally exposed to moisture. Class 3 includes wood used outdoors above ground, Class 4 covers wood in direct contact with the ground for exterior applications, and Class 5 addresses uses where treated wood is exposed to seawater and marine borers. Specifications for individual products typically list preservatives standardized for specific use classes along with the appropriate preservative retention levels [41]. Additionally, a significant challenge is ensuring the protection of mass timber products. Mass timber represents a range of composite materials, including glued- or nail-laminated timber, cross-laminated timber, laminated veneer lumber, and mass plywood panels, as their use in multi-story buildings has rapidly increased. This trend is driven by the need for sustainable construction and changes in construction codes [44]. Preservative treatments could improve durability and extend their use in structural applications; however, they may compromise other essential properties such as mechanical and bonding performances, processability, etc. [45,46,47,48,49]. In other words, the complex interactions between wood properties, preservative treatments, and adhesives may pose challenges for the applications of preservative-treated mass timber panels.

In the Chilean context, the economic feasibility of adopting alternative, environmentally friendly wood preservatives is paramount for industry stakeholders and policymakers. While these alternatives offer reduced environmental impact and are aligned with ESG and SDG principles, their higher initial costs and limited local availability may impede widespread adoption, particularly among small- and medium-sized enterprises. Additionally, social acceptance plays a critical role in regulatory transitions. In Chile, there is a growing awareness of the hazards associated with traditional preservatives; however, concerns about costs often overshadow environmental performance considerations in consumer decision-making, thus fostering social acceptance through educational campaigns, stakeholder engagement, and demonstration projects. To overcome economic barriers, government incentives (refer to policy and regulatory tools that promote the use of sustainable wood protection methods rather than direct financial subsidies), public–private partnerships, and investments in local production capacity could facilitate the gradual integration of safer wood preservatives. This strategy would help achieve sustainability targets while maintaining market viability and public trust.

Enhancing wooden buildings, optimizing resource efficiency, and ensuring the sustainability of wood from a protection perspective are crucial tasks that must align with sustainability principles. Using wood as a natural resource is insufficient to develop green and sustainable materials. Thus, it is essential to advance and implement innovative methods, technologies, and frameworks that enable wood to reach its full potential as a key resource for a sustainable future and a well-functioning circular economy. For instance, moisture-related issues cannot always be addressed solely through design-based protection. The European framework aimed at harmonizing service life prediction tools has revealed that durability cannot depend exclusively on active ingredients that target biodegrading organisms. This is particularly relevant for applications associated with the use of Class 3 and, to some extent, the use of Class 2, where the presence of water is crucial for the growth of decay fungi. Therefore, the performance of wood species, modified wood, or preservative-treated wood may rely on their inherent or enhanced biological durability and improved moisture dynamics that prevent the material from becoming wet or remaining damp. The Time of Wetness (ToW) is a critical parameter related to moisture dynamics and can be assessed through laboratory testing [41].

3.2. Relationship of Wood Protection with the SDGs and ESG Principles

The Sustainable Development Goals (SDGs) aim to establish a framework for the management and analysis of factors that promote socially responsible investment. One way to systematically address ESG (Environmental, Social, and Governance) factors is through five value-creation methods. However, the universality of these methods may be limited, as some are easier to implement in specific industries or sectors. Concerning this study, the central question is which option is superior, using preserved wood that provides long-lasting service or selecting naturally low-durability wood that requires replacement at least four times compared to its preserved counterpart? This highlights the importance of accelerating research and development to find preservation solutions that are less toxic and more aligned with ESG principles. These principles focus on promoting revenue growth, reducing costs, minimizing legal and regulatory challenges, enhancing productivity, and optimizing asset management and investments. From this viewpoint, it is crucial to consider how to protect these investments effectively, as demonstrated by the example of a sustainable building [50]. Consequently, the market encourages companies to produce integrated reports that cover economic, environmental, and social dimensions. This includes ESG criteria directly linked to the SDGs by addressing environmental, social, and corporate governance issues.

Three Sustainable Development Goals (SDGs) are particularly relevant regarding environmental criteria: SDG 6, which emphasizes clean water and sanitation; SDG 7, which focuses on affordable and clean energy; and SDG 13, which advocates for climate action. In terms of social criteria, the most significant SDGs include SDG 1, aimed at eradicating poverty; SDG 3, which targets health and well-being; and SDG 5, which promotes gender equality. Regarding corporate governance, SDG 8 highlights the importance of decent work and economic growth, SDG 16 seeks to ensure peace, justice, and strong institutions, and SDG 17 underscores the need for partnerships to achieve the goals. Additionally, SDG 11 strives to establish safe, resilient, inclusive, and sustainable cities and human settlements. In the long term, developing more responsible and circular solutions is essential. This involves identifying consolidators capable of effectively addressing specific wood degradation issues. By implementing various preservation mechanisms tailored to long-term needs, we can minimize the necessity for repeated treatments and decrease overall material consumption. However, the environmental and human health risks linked to conventional wood preservatives such as CCA, PCP, and creosote underscore the urgent need for sustainable alternatives that align with global sustainability objectives. Connecting ESG criteria to the SDGs for the wood preservatives industry highlights the urgent need for socially responsible companies and governments to advance key objectives. This is especially pertinent for SDGs 6, 7, and 13, given the central role of environmental considerations in the 2030 Agenda. For instance, wood preservatives that minimize leaching into water systems directly support SDG 6 while enhancing the durability of wood in energy-efficient buildings indirectly contributes to SDG 7 and SDG 13 by reducing carbon emissions. In the social domain, safer wood preservatives for workers and end users promote SDG 3 (health and well-being) and support fair labor conditions under SDG 8 (decent work and economic growth). Moreover, strong corporate governance structures that ensure transparency, responsible sourcing, and stakeholder engagement are aligned with SDGs 16 and 17.

The ongoing discussion about the challenges and opportunities of wood construction has highlighted the importance of national technical standards and regulatory frameworks in different countries [51,52,53]. Significant research has also focused on life cycle assessments and evaluations of broader sustainability impacts [54,55,56,57]. Additionally, a substantial amount of the literature has explored user preferences and the key factors that drive the adoption of wood for both structural and interior applications [58,59,60]. However, these investigations have predominantly relied on durability and protection methods as a robust proposition from an ESG perspective.

Consequently, there is a necessity for ongoing research and development to identify and validate novel preservative formulations with lower environmental impact and high technical performance. Investment in biocide research, biobased formulations, and innovative treatment technologies (such as thermal modification and furfurylation) will support the industry’s evolution. Equally important is fostering collaboration between regulatory authorities, academia, and industry stakeholders to comprehensively address technical requirements, environmental safety, and market demands.

Moreover, timber countries such as Chile must anticipate regulatory shifts and market expectations, preparing to deliver solutions that comply with future restrictions and contribute to broader Environmental, Social, And Governance (ESG) goals and the United Nations Sustainable Development Goals (SDGs). Failure to do so could impact competitiveness in international markets and slow the transition toward more sustainable construction practices.

Even though Table 1 does not present data regarding the volumes of wood treated in each country, it is evident that each nation has established clear protocols and standards for wood preservation practices. This is particularly notable in Sweden and other Nordic countries, where approximately 90% of the Pinus sylvestris treated with preservatives is produced by treatment facilities participating in the voluntary certification and quality control program NWPC. Furthermore, all countries referenced in Table 1 maintain regulatory agencies responsible for approving active substances and national standardization organizations defining wood technical requirements.

Upon analyzing the weaknesses and threats, it is evident that CCA-based preservatives and creosote pose potential environmental and human health risks [29]. The sustained long-term use of these hazardous chemicals [10] does not align with optimizing assets and investments under ESG principles. This misalignment arises from the possibility of regulatory changes regarding active substances, which could lead to investment losses for industries that do not adapt accordingly [50]. Moreover, climate change contributes to the emergence and spread of a wide range of forest pests, as elevated temperatures weaken the natural defense mechanisms of trees and facilitate the proliferation of fungi and insects. The aforementioned phenomena may considerably influence the quality and availability of timber resources for future harvesting. Recent advancements in machine vision technology have enabled the automated detection of grading singularities, thereby improving the reliability of timber selection for engineered applications [61,62]. Additionally, increasingly stringent environmental regulations are expected to limit the use of certain active substances in wood protection formulations. At the same time, industrialized construction using concrete, brick, and steel is making notable advances in sustainability and continues to hold a significant share of the construction market [63]. Therefore, to enhance competitiveness, the wood products industry must emphasize and communicate wood’s superior environmental performance, technical properties, and durability compared to conventional construction materials.

Many countries are demonstrating a strong political commitment and have developed strategies to promote the use of wood in the construction sector. However, it is essential to translate these strategies into actionable steps. To evaluate effective implementation methods, it is important to understand the knowledge levels and preferences regarding wood construction among both industry professionals and private homeowners. Furthermore, government policies aimed at promoting the sustainable management of natural resources are increasingly transitioning from isolated pilot projects to large-scale developments of social housing in eco-friendly neighborhoods and timber-based urban environments. These policies should actively encourage the application of wood protection treatments to ensure the durability of the material and foster environmental stewardship.

Protective treatments for structural timber, such as copper azole (CA), alkaline copper quaternary (ACQ), micronized copper azole (MCA), and chemical modification processes, have proven to be highly effective against wood-degrading biological agents [12,64,65,66]. According to research performed by [50], these treatments present a strong opportunity from an ESG (Environmental, Social, and Governance) perspective. These innovations directly support SDG 3 (Good Health and Well-being) by reducing exposure to hazardous substances for workers and communities, as well as SDG 6 (Clean Water and Sanitation) by minimizing leaching into water systems. Additionally, preservative-free wood modification methods, such as thermal treatment, acetylation, furfurylation, and, more recently, plasma-assisted modification [67], offer promising alternatives that reduce the environmental burden of chemical use, contributing to SDG 12 (Responsible Consumption and Production). Their demonstrated efficacy can enhance investment returns by directing capital toward promising sustainable solutions. One of the key advantages of these treatments is the extension of service life; hence, the appropriate protection of structural timber reduces the frequency of costly repairs and replacements [68]. By effectively protecting timber, stakeholders can ensure that wood remains a viable, sustainable, and long-lasting material in construction, thus contributing positively to climate goals and responsible resource management. Therefore, integrating ESG criteria into wood protection strategies can mitigate operational cost increases [50]. Recent advancements in the development of novel protection products and synergistic combinations of treatments have led to safer and more efficient solutions [14,69]. Additionally, SDG 11 emphasizes the importance of creating safe, resilient, inclusive, and sustainable cities and human settlements. Within this framework, the need for effective solutions to address the challenges associated with wood degradation becomes increasingly critical. When aligned with ESG principles, these innovations can reduce operational expenses by enabling more efficient production chains with minimized material losses [50], supporting circular economy principles.

The efficient use of raw materials, particularly end-of-life wood, is of significant importance. Wood products generally have three primary disposal pathways at the end of their service life: landfilling, incineration, and recycling. From a sustainability viewpoint, landfilling should be avoided, as it poses the risk of releasing hazardous substances into the environment. A study performed by [70] on end-of-life wood waste management concluded that identifying supply chain indicators would facilitate the transition to a circular economy of wood waste. The study established 12 key performance indicators (KPIs): transportation distance, waste collection strategy, waste separation strategy, moisture content and quality of screened waste, quality of the recovered wood, quality, and cost of the recycled wood, recycling facility location, quality, and price of the reusable materials, cascading potential, energy savings, reduction in landfill use, material circularity index. In 2023, the Chilean sawmill industry consumed 14.6 million cubic meters of logs, of which 3.6 million cubic meters were by-products considered raw materials for producing new products such as MDF and MDP. This indicates that more than 25% of these logs, which were previously regarded as waste, are now utilized as raw material [71].

To fully harness the benefits of wood as a sustainable construction material, it is imperative to implement robust protective measures to mitigate associated risks. A thorough review of regulatory compliance is essential to ensure that wood protection standards are stringent and aligned with in-service risk classes. Regulations and environmental and safety standards must be differentiated across all processing stages. Life cycle assessment and holistic monitoring of sustainability indicators beyond greenhouse gases are imperative to guide responsible practices [72]. Furthermore, these regulations must be performance-based, ensuring that bio-based surface protectants are not equated with genuine wood preservatives when they fail to provide comparable levels of protection. As the market increasingly emphasizes recyclability and circularity, supported by certification systems that evaluate environmental impact and carbon footprint, these innovations play a vital role in advancing SDG 13 (climate action) by reducing emissions associated with material replacement and waste incineration. However, economic feasibility poses a significant challenge to widespread adoption; unless new treatments can compete on cost, their implementation may be limited despite their sustainability benefits. Additionally, long-term field testing and establishing consumer trust are essential for successfully scaling novel technologies. Consequently, to fully capitalize on the sustainability potential of wood preservatives, future strategies should incorporate lifecycle assessments, affordability considerations, and risk-based decision-making frameworks that align with ESG principles and the SDG agenda.

4. Conclusions

This study provides a critical comparative overview of wood preservation regulations, contrasting international frameworks with the Chilean context while aligning them with ESG criteria and the Sustainable Development Goals (SDGs). A crucial finding is that while Chile complies with certain international standards, its regulatory framework remains conservative regarding the adoption and innovation of preservatives. Unlike countries that have advanced decisively toward more sustainable practices, integrating low-toxicity preservatives and employing performance-based evaluations, Chilean standards rely heavily on traditional preservatives, such as CCA.

For Chile and other emerging markets, it is imperative to align wood protection strategies with ESG principles and SDGs to guarantee long-term structural performance, resource efficiency, and market competitiveness. Chile’s current position underscores a need for regulatory evolution that supports innovation while ensuring environmental and human safety. By advancing to a risk-based assessment model, improving data on local species durability, and expanding acceptance of globally standardized preservatives, Chile can significantly enhance its timber industry competitiveness and sustainability credentials.

From a policy perspective, it is essential to align national standards with ESG and SDG principles, particularly SDGs 3, 6, 12, and 13, to modernize wood protection regulations and contribute effectively to global environmental initiatives. Strategic investments in research and development, complemented by targeted incentives and public–private partnerships, will drive the widespread adoption of eco-efficient preservatives. Such alignment will mitigate ecological risks and position Chile as a leader in sustainable timber practices.

Future research must prioritize evaluating the long-term effectiveness of alternative preservatives, enhancing cost efficiency, and strengthening policy frameworks to enable a global transition toward sustainable wood preservation. A robust institutional framework will give countries a distinct strategic advantage, fostering stability and ensuring continuous growth within the wood preservation sector. By integrating new technologies and adopting more sustainable practices, countries that adapt to emerging innovations will undoubtedly lead in developing a resilient and forward-thinking timber preservation industry.