The role of attributes defining intervention concepts in international doctrinal documents on built heritage

Purpose – Attributes conveying cultural significance play a key role in heritage management, as well as in differentiating interventions in built heritage. However, seldom the relation between interventions and attributes, either tangible or intangible, has been researched systematically. How do both tangible and intangible attributes and interventions relate? What attributes make interventions on built heritage differ? Design/methodology/approach – This paper conducts a systematic content analysis of forty-one internationaldoctrinaldocuments — mainlyadoptedbytheCouncilofEurope,UNESCOandICOMOS,between 1877 and 2021. The main aim is to reveal and compare the selected eight intervention concepts, namely — restoration (C1), preservation (C2), conservation (C3), adaptation (C4), rehabilitation (C5), relocation (C6), reconstruction (C7) and renewal (C8) — and their definitions, in relation to attributes, both tangible and intangible. The intensity of the relationship between intervention concepts and attributes is determined based on the frequency of the mentioned attributes per intervention. Findings – There were three key findings. First, although the attention to intangible attributes has increased in the last decades, the relationship between interventions and tangible attributes remains stronger. The highestfrequencyofreferencingthetangibleattributeswasidentifiedin “ relocation ” and “ preservation, ” while the lowest was in “ rehabilitation. ” Second, certain attributes play contradictory roles, e.g. “ material, ” “ use ” and “ process, ” which creates inconsistent definitions between documents. Third, as attributes often include one another in building layers, they trigger the intervention concepts in hierarchical patterns. Originality/value – This paper explores and discusses the results of a novel comparative analysis between different intervention concepts and definitions, with a particular focus on the attributes. The results can support further research and practice, clarifying the identified differences and similarities.


Introduction
To ensure heritage is well-managed and appreciated by the society of present and future generations, international governmental and nongovernmental organizations such as The United Nations Educational, Scientific and Cultural Organization (UNESCO), Council of

Attributes and intervention concepts
Europe (CoE), and International Council on Monuments and Structures (ICOMOS) have been developing international doctrines for over half a century.These documents play a pivotal role by providing statements or principles and guidelines for the conservation and management of places of cultural significance, thereby establishing a professional ethics role in guiding the conduct of heritage conservation practice (Taylor, 2004;Lin et al., 2023).These documents, however, are not meant to be perfect or tailored to a specific context, given their need to bridge all countries, cultures and priorities (from the experts) involved in their drafting.Consequently, the concepts and policies guiding built heritage interventions are subject to continuous evolution over time (Jokilehto, 2007).In supporting the definition of intervention concepts, during the last decades, although international doctrinal documents have defined intervention concepts with different levels, scales and activities (ICOMOS Canada, 1983), their definitions and categories are often nonaligned and omitted between documents and organizations (Lin et al., 2023).
Moreover, cultural significance is expected to influence the selected category/level of intervention on built heritage (ICOMOS Canada, 1983).Cultural significance is decoded by the conveyed values (Pereira Roders, 2007) and attributes (Veldpaus, 2015).Values justify why heritage is listed, and the attributes characterize the resources (tangible and intangible) that convey such values (Veldpaus and Roders, 2013).Unlike values, attributes follow "a more hierarchical pattern of including and overlapping each other, while the values exist in parallel to each other, although they are usually ranked in importance, whenever set concerning each other, to support decision-making" (Veldpaus, 2015).
Furthermore, as the range of attribute categories expanded (Sullivan, 2004;Jokilehto, 2006;Landorf, 2009;Vecco, 2010;Araoz, 2011;Labadi, 2013;Veldpaus, 2015), the heritage paradigm shifted from tangible to intangible aspects in recent decades (Ruggles and Silverman, 2009;Silva, 2020); scholars have highlighted the object of preservation remains in a tangible and physical approach (Ruggles and Silverman, 2009).Ongoing debates also focusing on whether certain intervention concepts are in favor of tangible or intangible attributes, such as restoration, renewal or reconstruction, especially in different cultural contexts (Mastero, 2006;Mansfield, 2008;Kwanda, 2009;Park, 2014;Okahashi, 2018;Sharma, 2019).This underscores the idea that as the meanings of the significance and attributes changed between cultures (ICOMOS, 1994) and over time (ICOMOS Australia, revised 2013;Bond and Worthing, 2016;De la Torre, 2002), our intervention will impact how future generations perceive the conserved heritage and engage new interventions, including the use of new digital technologies and artificial intelligence (Ceccarelli, 2017).In this dynamic context, the focus should be not on preventing change but on finding alternative ways to enact change without compromising significance (Bond and Worthing, 2016, p. 162).
Therefore, understanding the relationship between interventions and attributes, as well as further contribute to the definition process of intervention concepts, becomes essential.This paper aims to address the following questions: First, what is the overall distribution of attributes per intervention concept?Second, what aspects of attributes trigger specific intervention concepts?Third, which attributes lead to these differ from other interventions?Using a qualitative approach and systematic content analysis, the intensity of the relationship is determined based on the frequency of the mentioned attributes per intervention.

Research methodology 2.1 International doctrinal documents
This paper conducted a systematic content analysis of international doctrinal documents.This mixed-method approach combines qualitative and quantitative statistics, enabling the systematic collection, analysis and presentation of the narratives that embedded intervention concepts in international doctrinal documents.This methodology has been applied to identify the role of values in defining intervention concepts (Lin et al., 2023).
This research selected the concept "intervention," as the general concept to address all the variations in man-made activities applied to built heritage, in order to ensure its survival over time, against the natural process of degradation (Pereira Roders, 2007), e.g.conservation, restoration and rehabilitation.A larger sample of 519 international doctrinal documents was selected due to their reference to cultural heritage.They were examined by searching the keywords "intervention," and "intervention concepts"-"conservation," "preservation," "restoration," "adaptation," "reconstruction," "rehabilitation," "relocation," "renew" and "attributes" as well as attribute-related contents in the glossary and terminology sections.If those sections were unavailable, the definitions of the intervention concepts were deduced by the content analysis of the integral documents.
After the examination, this research selected and analyzed nearly seventy international doctrinal documents, adopted during 1877-2021, revealing a broad geographical spread by their origin, ranging from Europe to Asia and the Pan-Pacific (Table 1).Out of these, forty-one documents have been identified with relationships between intervention concepts and attributes.They are, respectively, four (10%) international doctrinal documents adopted by the UNESCO, twenty-four (58%) by ICOMOS and nine (22%) by the CoE.Two documents considered as ICOMOS have been also prepared with other organizations, as, e.g.The International Committee for the Conservation of the Industrial Heritage (TICCHI).Four documents (9%) were adopted by other organizations-as the Society for the Protection of Ancient Buildings (SPAB), ICOM Architecture and Architect's Council of Europe.They were considered the first international doctrinal documents on cultural heritage before or at the beginning of the establishment of these international organizations.

Cultural attributes
On the one hand, despite the previous development of the Nara Grid by Van Balen (2008) for assessing the chosen case study, this paper has revealed that the complexity of the attributes cannot be comprehensively assessed through these categorizations.This limitation stems from identifying some categories that exhibit overlapping or implicit characters.On the other hand, an attributes taxonomy theoretical framework was created by Veldpaus (2015) to enhance the understanding of the attributes and to facilitate the identification process.However, considering the specific focus of this research on built heritage, it became evident that Veldpaus (2015)'s framework which primarily targeted an urban scale did not adequately address the attributes pertinent to built heritage.Among the five overarching categories of tangible attributes, only two main categories were found applicable to built heritage: "building elements" and "urban elements" under objects.Another was the "group of buildings" and "building(s) þ context" under "ensemble/complex."Recognizing the inadequacy of suitable attribute categories of built JCHMSD heritage during the analysis, this paper proposes an attributes theoretical framework with two categories: tangible and intangible attributes (Table 2 and Table 3).Each category comprises subcategories, with eight subcategories falling under tangible attributes and six under intangible attributes.These subcategories were referenced from the prior framework by Veldpaus and Pereira Roders (2013), Veldpaus (2015), The Nara Document (ICOMOS, 1994), The New Zealand Charter (ICOMOS New Zealand, revised 2010), The Burra Charter (ICOMOS Australia, revised 2013) and Operational Guidelines (UNESCO, revised 2021).
The method included three steps: (1) The author extracted the sentences which involved the terminology of intervention concepts and attributes, including contents implying their explanations, interpretation, and definition from the international doctrinal documents.
(2) The extracted contents were structured and classified in pre-coding according to the attributes theoretical framework (Table 2 and Table 3).When some of the descriptions  1.

Attributes and intervention concepts
may include more than one subcategory or in both tangible and intangible simultaneously, the authors classify them both during the identification process.
(3) Analysis and comparison of the structured data to reveal (1) the frequency of mentioning the attributes within the selected documents and (2) comparing the relationships between attributes and the selected intervention concepts from different international doctrinal documents and organizations.

Findings: the relationship between attributes and intervention concepts 3.1 Overall attributes across eight intervention concepts
Concerning the focus ranging between the tangible and intangible attributes, results (Figure 1) revealed that only "rehabilitation"(C5) exhibited a predominant focus on intangible attributes, with only a minor reference to tangible attributes (8%).Conversely, "relocation" (C6) (88%) and "preservation" (C2) (81%) both primarily emphasized tangible attributes, with references to tangible attributes being seven to three times more frequent than those to intangible attributes.

JCHMSD
Instead of sharing similar percentage patterns between "preservation"(C2) and 'conservation"(C3), "conservation" presents more focus on the intangible attributes, especially in "use and function" and "craftsmanship and techniques" (Figure 2).
While both "rehabilitation" (C5) and "adaptation" (C4) displayed strong relations to "use and function," "adaptation" maintained a more equitable distribution between tangible and intangible attributes.It incorporated a wider range of categories, including "material," "settings," and others (see Table 4).
In the following sections, the subcategories will be delineated within each intervention concept to elucidate the attributes that wield substantial influence on the intervention concepts.

Conservation (C3)
Within the pool of forty-one documents, twenty-five (61%) were found with attribute-related content related to "conservation".Notably, "conservation" is the only concept that references to all attribute categories.

Attributes and intervention concepts
Two documents (UNESCO, 2011;ICOMOS, 2021) focused on the role of the "management system" in "conservation."This not only included the "traditional and customary systems" (UNESCO, 2011) but also the "system" which treated the military heritage "network as a whole" (ICOMOS, 2021).
While the attention to tangible and intangible attributes was nearly balanced, certain attributes such as "style," "surface," as well as "craftsmanship and technology" were absent from "adaptation."

Rehabilitation (C5)
Five documents have been identified with attribute-related contents pertinent to "rehabilitation".Notably, the emphasis in these documents varied between tangible and intangible attributes.Among the five documents, only one document (UNESCO Bangkok, 2009) mentioned the aspect of tangible attributes.Specifically, it mentioned the importance of keeping the "historic character of the structure" during the "rehabilitation" process.
One common attribute found in all (four) documents (UNESCO Bangkok, 2009; ICOMOS New Zealand, revised 2010; ICOMOS Australia, revised 2013; ICOMOS China, 2015) was "location," encompassing the "site" and conservation "in situ." Two documents (ICOMOS New Zealand, revised 2010; ICOMOS China, 2015) mentioned "setting" in "relocation."Particularly, "relocation" is considered as a viable option when natural disasters or changes destroy the "natural setting" (ICOMOS China, 2015) of the heritage site.
Two documents addressed the attribute of "relation," highlighting the importance of the "ongoing association" (ICOMOS New Zealand, revised 2010) and "significant links" (ICOMOS Australia, revised 2013) between the sites and structures.Notably, the Burra Charter (ICOMOS Australia, revised 2013) extends its concern to buildings, works or elements specifically "designed ready to be removable" or that "already have a history of relocation," a perspective not mentioned in other documents.
Additionally, two documents emphasized the role of "use and function" (UNESCO Bangkok, 2009; ICOMOS Australia, revised 2013).The Hoi An Protocol (UNESCO Bangkok, 2009) emphasized that the new location should contain a sympathetic environment of "building . . .function."This perspective aligns with the "appropriate use" outlined in the Burra charter (ICOMOS Australia, revised 2013).

Reconstruction (C7)
A total of ten documents (24%) were identified with attribute-related contents in "reconstruction." Six documents (ICOMOS, 1964(ICOMOS, , 1996b(ICOMOS, , 2003b;;UNESCO Bangkok, 2009; ICOMOS New Zealand, revised 2010; ICOMOS Australia, revised 2013) were found referencing "material" in "reconstruction."Notably, two documents (ICOMOS New Zealand, revised 2010; ICOMOS Australia, revised 2013) emphasized the use of "new material" as a distinguishing factor between "reconstruction" from "restoration."In contrast, the "traditional material" (ICOMOS, 2003b) is encouraged for use in wall painting, which contradicts the perspective presented in the aforementioned documents (ICOMOS New Zealand, revised 2010; ICOMOS Australia, revised 2013.Also, the Declaration of San Antonio (ICOMOS, 1996b) highlighted the misuse of "reconstruction" in the context of archaeological sites when it involved the introduction of "new materials" and led to alternations in the site's "appearance." Instead of distinguishing new or traditional material, the Venice Charter (ICOMOS, 1964) mentioned only "recognizable material and form" when explaining the other two concepts-"anastylosis" and "reinstatement"-within "reconstruction." Four documents (ICOMOS, 1996b(ICOMOS, , 2011a;;ICOMOS Australia, revised 2013;ICOMOS China, 2015) addressed "location" relating to "reconstruction."Besides "sites" (ICOMOS, 2011a;ICOMOS China, 2015), more detailed information was found, especially in the China Principle (ICOMOS China, 2015), such as "lost sites," "footings," "ruins or ruins of the footings" concerning human or natural disasters.

Attributes and intervention concepts
Charter (ICOMOS Australia, revised 2013) indicates that "reconstruction" may be seen as part of the "use" and "practice" itself in some cases.Two documents (ICOMOS, 2003b;ICOMOS China, 2015) were found to be related to "craftsmanship and techniques" in "reconstruction.""Traditional techniques" (ICOMOS, 2003b) were endorsed, particularly wall painting.Although "reconstruction" for presentation and interpretation was generally discouraged, the China Principle (ICOMOS China, 2015), mentioned the potential use of "modern technology" (ICOMOS China, 2015), such as "drawings, photos and sketches, and models, or "virtual reality presentations" based on accurate archaeological and documentary evidence.
Additionally, unique subcategories were identified.Only one document (ICOMOS New Zealand, revised 2010) mentioned that the "setting" can be reconstructed.Another document (ICOMOS, 2008a), introduced "process" and "relations" in "reconstruction", addressing both tangible and intangible aspect by noting that "the spirit of place is a continuously reconstructed process, which responds to the needs for change and continuity of communities . .." (ICOMOS, 2008a).
3.9 Renew/Renewal (C8) Six documents (14%) were identified with the relationships between attributes and "renew/ renewal." Three documents (ICOMOS, 1999c(ICOMOS, , 2003b(ICOMOS, , 2008b) made reference to "craftsmanship and techniques" in "renew/renewal."These documents endorsed the use of "traditional techniques," considering them integral to the "traditions of renewal" and "practices of artists and craftsman" (ICOMOS, 2003b), particularly concerning wall painting.Furthermore, "modern techniques" concerning the conservation of the spirit of place (ICOMOS, 2008c) enhanced diversity and played a crucial role in the constant renewal of the documentation related to the spirit of place.
In addition to "craftsmanship and techniques," the concept of "renew/renewal" displayed diverse and equitable relations with other attributes, such as "location," "surface" and "material."Notably, two documents (ICOMOS, 1981(ICOMOS, , 1999c) ) provided more detailed insights into the subcategory of "surfaces."One document (ICOMOS, 1981) mentioned activities, such as cleaning "fallings" and replanting plantation "mature specimens," while the other (ICOMOS, 1999c) emphasized the duplication of "surface finishes" to the greatest extent possible during the renewal process.

Discussion
The discussion of the findings regarding the relationship between interventions and attributes in international doctrinal documents is as follows: Dominance of Tangible Attributes.Although the attention to intangible attributes has increased in the last decades since the Nara Document (1994) (西和彦 et al., 2021), the relationship between interventions and tangible attributes remains higher-seven to three times-more than the intangible attributes, especially in "preservation" and "relocation."Only "rehabilitation" was the only concept referencing more intangible than tangible attributes among the other seven.This finding reinforces the assertion made by Ruggles and Silverman (2009) that "preservation" remains primarily tangible-driven, indicating that the majority of intervention concepts in these documents prioritize tangible heritage aspects.
Attributes bring differentiation in concepts.Comparing concepts often used interchangeably, this paper found distinctions in their relationships with tangible and intangible attributes.For instance, "conservation" was found closely related to intangible attributes, such as "use and function," "craftsmanship and techniques" and "process."JCHMSD Conversely, preservation" is strongly associated with tangible attributes, such as "setting," "form" and "material."Similar distinctions are observed between "adaptation" and "rehabilitation."Despite both of the concepts focused on "use and function," the former concentrates more on tangible attributes, such as "material," "structure," "fixtures and fittings" and the latter barely mentioned any.Moreover, even when interventions appear similar in their aim to substitute or alter the existing, the results demonstrate that they focus on different attributes.For example, in "adaptation" and "renewal," the former leans toward "use and function" as well as "manage system," while the latter emphasizes "technology" and "surface." Attributes trigger interventions in hierarchical patterns.Unlike values that tend to perform dynamic relationships between intervention concepts (Lin et al., 2023), attributes were found easier related to be more than one intervention concept at the same time.This is probably because when attributes are mentioned, they are hierarchical and involve one with the others, such as "material" under "surface" or "structure" under "material."This finding is aligned with the theory of Veldpaus (2015).Also, this hierarchical phenomenon might suggest that interventions may have unforeseen impacts on multibuilding layers when implemented.
Contradictory roles of attributes.Certain attributes play contradictory roles in the same intervention concepts across different documents.For example, "new materials" and "traditional materials" in "reconstruction."While The Manifesto (SPAB, 1877) addressed that modern techniques and materials are acceptable in restoration, it is going against the idea in the Burra Charter (ICOMOS Australia, revised 2013) and New Zealand Charter (ICOMOS New Zealand, revised 2010) of using "traditional material" in restoration.Within these two charters, "new material" is set as a criterion to distinguish between "restoration" and "reconstruction."Moreover, the Burra Charter (ICOMOS Australia, revised 2013) addressed that "reconstruction" may be perceived as part of the "use" and "practice" itself, emphasizing not just the material aspect but also the intangible dimension of continuity and meaning.This finding is aligned with the theory of Kwanda (2009), Park (2014) and Okahashi (2018).
Paradoxical documents.Some documents adopt paradoxical positions referencing multiple international documents rather than creating regional definitions, for instance, the Hoi An Protocol (UNESCO Bangkok, 2009) draws from various documents.Take "reconstruction" for example; while documents-Burra Charter (ICOMOS Australia, revised 2013) and New Zealand Charter (ICOMOS New Zealand, revised 2010)-mention "earlier state" in their definition, another document like the Appleton Charter (ICOMOS Canada, 1983) only mentioned, "vanished or irreversibly deteriorated resources."The problem is that these documents didn't mention "which state" they are returning to and from which criteria they determine "vanished or irreversible."Furthermore, referencing multiple documents may mean including different mindsets simultaneously, leading to misinterpretation.This finding highlights the need for more customized regional documents.
Emerging attributes categories.New categories were found to suggest more attention.For example, "Vegetation" and "lighting" would affect the atmosphere, setting, visual setting and emotional affection; "interior" and "fixtures and fittings" shape the "use"; "movement" and other senses, e.g.sound and smell are also hard to identify in the researched documents.This observation aligns with the theories of Bond and Worthing (2016) and Ceccarelli (2017), suggesting the identification of new attributes in the future may necessitate reevaluations and shifts in definitions.

Conclusion
This paper underscores the tangible-centric nature of intervention concepts within international doctrinal documents concerning built heritage, emphasizing the imperative for increased attention to intangible attributes.Different patterns influencing the relationship between Attributes and intervention concepts intervention concepts and attributes of cultural significance have been explored.While the role of values brings a dynamic relationship, the role of attributes triggers intervention concepts in hierarchical patterns.This implied that a single intervention concept would impact multibuilding layers, from the setting to the fixture and fitting of the interior, and from the relation to use.Future research can focus on setting up a more detailed attribute category, especially from the new technologies and materials in intangible aspects.As the definitions evolve from time and space, it is necessary to revisit the interventions, their definitions and philosophy at intervals.Future researchers can also compare the relationship between intervention concepts and attributes among stakeholders.However, defining interventions solely based on attributes in not enough.Other aspects such as time layers (earlier/later), actions and aims should also incorporated into the refining process.Last but not least, the attributes of cultural significance and interventions should always look at their context when analyzing.
Identifying the role of "what" is affecting or being affected by "which" interventions can be a chance to provide a fundamental reference for decision-makers and related stakeholders to continue and reform the significance.This paper serves as a foundation for further research and practical applications, elucidating distinctions and commonalities across diverse cultures, places and times.
Figure 1.The percentage of tangible and intangible attributes in each intervention Figure 2. The eight intervention concepts and their proportional references to the fourteen subcategories (tangible and intangible attributes)

Figure 2
Figure 2 This table was created by Mi Lin Table

In total: 41 documents / Concepts menƟoned in each sub-category Number of Documents idenƟfied with aƩributes
Source(s): This table was created by Mi Lin