## 3 Research Method  
Case studies were employed to classify and consolidate data regarding contemporary high-rise residential wooden structures, thereby enabling a systematic examination and evaluation of their architectural and structural attributes (Figure 1). The adoption of case study analyses stands as a widespread approach in evaluations linked with the built environment [72; 73; 74]. This investigation contained a thorough scrutiny, embracing a collective of 51 [out of a total of 56 buildings in the Council on Tall Buildings and Urban Habitat (CTBUH) database] [50] tower case studies. These towers were either in completion or under construction, with a distinct focus on structures primarily composed of timber. The criteria for selection comprised buildings comprising eight stories or more, with data drawn from documentation sources by (CTBUH). CTBUH holds significant acclaim for its authoritative role in defining the heights of skyscrapers worldwide, earning the esteemed title of 'The World's Tallest Building'. Beyond this, CTBUH spearheads the 'Buildings of Distinction' initiative, which celebrates exceptional architectural designs by installing public signboards and plaques. Operating on a universal scale, CTBUH works as a pivotal stage for disseminating leading-edge knowledge and facilitating commercial interactions within the realm of tall building construction and urban development. Through its multifaceted endeavors, CTBUH not only establishes standards but also fosters innovation, collaboration, and recognition within the architectural and urban planning communities, contributing to the ongoing advancement of the built environment. The analyzed structures in this paper were geographically distributed, encompassing thirty-three locations across Europe, as seen in Figure 2 (with nine from Norway, nine from Sweden, five from France, five from Finland, two from the Netherlands, two from Germany, and one from Italy), seven from North America (comprising four from Canada and three from the USA), and seven from the UK, besides four from Australia, as outlined in Appendix A. In the realm of wooden residential constructions, decision-making chiefly adheres to architectural and structural necessity-driven requisites, alongside the primary purpose of the edifice. The principal attributes encompass the subsequent factors:  
Architecturally:  
* Core arrangement impacting the configuration of vertical movement and the allocation of shafts. * Building form influencing sizes and pattern of the floor slabs. * Structurally:
* Structural system influencing disposition and sizes of the load-bearing constituents. * Structural material affecting the proportions of the load-bearing members. The core planning scheme advocated by [33] was selected for implementation, owing to its comprehensive structure, encapsulating the following groupings: (1) central core, (2) atrium core, (3) external core, and (4) peripheral core. Building forms are classified as follows [33]: (1) prismatic, (2) setback, (3) tapered, (4) twisted, (5) tilted, and (6) free forms, as outlined in Appendix B. Structural materials could be classified into two primary clusters: (a) 'timber' or 'all-timber', and (b) composite or hybrid materials, which entail arrangements, timber combined with concrete, timber combined with steel, or timber combined with both concrete and steel. Our study particularly focuses on main structural elements such as columns and beams, while disregarding the examination of slabs. It is crucial to highlight that the material makeup of structural members on the basement floor does not change the categorization of the load-bearing system. Figure 1: Methodology flowchart (image created by authors). According to the categorization of structural materials, a primary criterion for a structure to be classed as 'timber' is that both its main vertical and horizontal load-bearing components are completely crafted from timber [50].