Why is mass timber sustainable?

JESSICA MANGIN

March 28, 2022

This post is the first in a series as we continue to work with mass timber at Amy Gutmann Hall and Edelman Fossil Park & Museum of Rowan University. We hope you will follow along!

Mass timber construction is on the rise nationwide. In addition to its intrinsic value as a material that contributes to attractive, warm spaces that people gravitate toward, mass timber is also lauded as a sustainable construction strategy, largely due to its ability to reduce the carbon footprint of the built environment. But what is mass timber’s sustainability story beyond carbon? KSS takes an integrated approach that explores sustainability through a framework of four broad lenses–environment, social, human, and economic. While each lens considers sustainability from an important and distinct perspective, they are each deeply interconnected. Through this framework, we see the holistic value of mass timber and its unique opportunities for impact at the human, building, community, and global scale.

Environment: Reducing the Built Environment’s Carbon Footprint

Mass timber, if locally and responsibly sourced, can lower the carbon footprint of buildings through reduced carbon. Just three materials — concrete, steel, and aluminum — are responsible for 23% of total global carbon, and mass timber offers a carbon-smart alternative that can reduce those emissions by 15 to 20% (Architecture 2030, Science). Structural systems in particular, which are most commonly high-emission materials like concrete and steel, are a critical opportunity in the design process. Roughly 50–80% of a building’s embodied carbon emissions are in the structure, making a mass timber structure an impactful solution when it comes to the carbon footprint of the built environment. In addition to lower embodied carbon in procurement and manufacturing processes, mass timber is a renewable resource that sequesters carbon. Forest ecosystems are one of the largest natural carbon sinks in the world, absorbing more carbon from the atmosphere than they release. In turn, forest products such as mass timber can sequester carbon for generations (Business View).

The key part of mass timber’s carbon solution though is local and responsible sourcing. This requires thoughtful procurement from climate-smart forests that are responsibly managed and local to projects, therefore minimizing carbon emissions associated with transport. Forest products are certified by organizations such the Forest Stewardship Council and the Sustainable Forestry Initiative, which promote practices that ensure forests preserve biodiversity, benefit local communities, and can sustain harvesting over time.

Human: Holistic Health

Mass timber offers a connection to nature that benefits human physiological, cognitive, and psychological health. Built environments with exposed wood offer improved air quality, moderation of humidity, and can also lower stress; a 2011 study demonstrated that the appearance of wood lowered stress responses as well as heart rate/variability and blood pressure. These spaces also impact cognitive functioning, improving the ability to learn and even leading to better test scores (Economics of Biophilia). The presence of natural materials like wood supports biophilic responses that positively impact psychological health and wellbeing including “greater emotional restoration, and lower instances of tension, anxiety, anger, fatigue, confusion, and total mood disturbance” (Terrapin Bright Green). For owners, the benefits to human health improve occupant comfort and satisfaction which consequently increases marketability and overall asset value.

Social: Community Resilience

The growing mass timber market continues to drive support for responsible forest management, which seeks to conserve forests in communities that often have ecological, cultural, and economic significance. The sustainable development of forests includes practices that avoid overly dense forests, mitigating the risk of wildfire spread which can destroy communities, wildlife habitats, and emit carbon. The practice of maintaining forest cover and limiting clear-cutting can also influence local watershed management, as forests reduce erosion and flooding impacts, particularly in coastal and valley communities. Improved soil and water management can also positively impact neighboring agricultural land and strengthen agroforestry ties.

In addition to natural disaster resilience, mass timber also has the potential to support local economies, particularly forest-dependent communities. The mass timber market generates millions of jobs related to forest production and processing, and provides a unique connection between rural and urban communities. Strategic partnerships between industry partners and local workforces can also provide opportunities for employment and training in mass timber technology. The Forest Stewardship Council has outlined the many layers of impact of responsible forestry in a comprehensive diagram, here.

Economic: Advantages of the Bioeconomy

Investing in mass timber buildings is not just sustainable from a human, environmental, and social perspective, but has the potential to support long-term economic growth and profitability as well. By sourcing from responsibly managed forests, mass timber reconsiders the take-make-waste cycle and leverages the circular economy and the benefits of renewability, biodegradability, and disassembly.

Much of the economic value of mass timber goes to building owners who benefit from reduced project costs as a result of faster construction due to prefabrication, fastener technology, and overlapping sequencing with other trades, smaller labor crews, and lighter foundations (CTBUH). In addition, owners benefit from the marketability of these aesthetically pleasing spaces; exposed mass timber can be a desirable finish that is covered by core and shell budgets and therefore can reduce the cost of tenant fit-outs.

Look out for upcoming posts from KSS on all things mass timber from procurement methods to project case studies.