Page 55 - FDMAsia MarApr 2025

MATERIALS 53
www.fdmasia.com | FDM ASIA MAR/APR 2025

on the IPCC methodology, native forests have sequestered It has effectively assessed the city of Santiago’s potential
ap- proximately 67,474 kt of CO2 per year, while plantations to function as a wood carbon sink or ‘Second Forest’.
have captured around 74,935 kt of CO2 per year, averaged Through the analysis of real estate tax databases, construction
over the most recent eight-year reporting period from 2013 permits, timber building typologies, and carbon accounting

to 2021. models, this study quantifies the carbon stored in the city’s
This means that, on average, native forests have captured timber structures, revealing storage volumes comparable to
5077 kg CO2/ha per year, and plantations 21,440 kg CO2/ha those of native forest ecosystems in some urban areas.
per year. However, most of the carbon captured by plantations Additionally, the analysis shows that urban expansion
is assumed to be released later during harvest. In contrast, zones tend to increase the use of timber in their constructions,
over the eight years of study, the wooden surface area in the while areas undergoing vertical densification tend to reduce
case study has stored 1002 kg CO2/ha per year. the presence of timber.
However, this figure could increase in some peripheral This finding is significant in terms of CO2 storage in the
municipalities to up to 7607 kg CO2/ha per year, while built environment and the impacts of vertical densification

municipalities undergoing a densification process could release using traditional materials other than wood.
up to 3794 kg CO2/ha per year due to the replacement of Moreover, maintaining a record of CO2 stored in the built
low-height wood buildings by taller concrete structures. environment not only improves the understanding of buildings’
This indicates that wood constructions in the built environment carbon mitigation potential but also lays the groundwork for
have the potential to retain annual CO2 amounts comparable developing tools and public policies aimed at promoting low-
to a native forest in the case study scenario, although this emission, CO2-storing construction practices.
potential may be significantly influenced by building trends. Data generated by studies like this are essential for creating

That said, through its wooden constructions and the regulatory frameworks that encourage timber construction,
timber products used in its structures, the city of Santiago has especially in taller buildings, thereby strengthening urban
managed to retain a significant part of the biogenic carbon carbon storage strategies.
originating from forests. Such methodologies also allow for extrapolation to other
The results have shown that this carbon may have been urban cases in countries lacking comprehensive material
stored for a few decades in some younger municipalities and intensity records or timber use data within the built environment.
for up to hundreds of years in the case of downtown Santiago. Finally, it is recommended that future studies focus on
Furthermore, the rate of wood construction in some developing more accurate methodologies to quantify and
expanding municipalities indicates that the annual CO2 storage characterise biogenic carbon storage in the built environment,

from new buildings may even surpass the per-hectare capture particularly in regions where this methodology may not be
of native forests in the Chilean case. suitable due to the stated limitations.
This highlights a temporal and quantitative potential for Additionally, it would be valuable for future research to
annual CO2 capture, suggesting, to some extent, the city’s explore how urban planning trends influence the permanence
potential as a “Second Forest” in relation to its biogenic of biogenic carbon in timber within the built environment,
carbon storage capacity. as well as to examine future scenarios for high-rise timber
This study presents a methodology for quantifying biogenic buildings and their potential impacts on urban biogenic

carbon and stored CO2 in timber structures within the built carbon stock. FDM
environment. ENQUIRY NO. 2201