The 2020 edition of the North American Mass Timber State of the Industry Report introduced the concept of The Marshall Effect. The Marshall Effect projects the pace of global mass timber construction and the resulting North American carbon sequestration. It is named in honor of SmartLam’s Steve Marshall for his mass timber market development contributions.
Every 1 million board feet of increased lumber demand will lead to adding 3,000 acres of new working forest land. By 2034, the 12.9 billion board feet of new lumber demand arising from mass timber will have led to the establishment of nearly 77 million acres of new forest land. As perspective, that would be an increase of about 4% of the current North American forest land area. It is estimated that, on average, each acre of working forest land can sequester a total of about 13 tons of carbon over a rotation, but only 50% of that amount is credited against carbon emissions since about half of a tree’s merchantable volume is utilized as long-lived forest products.
The practical capacity* of the mass timber manufacturer’s operating in 2019 is 15,494,000 cubic feet of panels allowed for use in structural applications.The estimated demand for mass timber used in North American buildings in 2034 will be 576,000,000 cubic feet. This means mass timber manufacturing practical capacity will need to increase by a factor of nearly 40 by 2034 to meet the increase in demand for mass timber used in buildings. *Practical capacity is currently estimated at 65% of nameplate capacity. The gap between practical and nameplate capacity may shrink in the future as mass timber panel production becomes more standardized (i.e., mass timber panels are produced to standard sizes and thicknesses as opposed to the current.
Of the main structural material choices for buildings, wood is the only option that can be sustainably sourced and that can also store rather than emit carbon. Collaborative design processes bring designers, builders, and manufacturers together in a scenario that can more closely control the sourcing, waste, and embodied carbon emissions of a building. Products sourced from rural areas and erected largely in urban centers bridge the urban/rural divide. When sustainably harvested, mass timber products are widely supported and endorsed in diverse communities. Building practices that minimize waste, such as modular mass timber and prefabricated components, are often also associated with improved and more diverse working conditions, contributing to equity and social sustainability of communities. Sustainably sourced wood does not necessarily come at a premium, but sources should be vetted before purchase to be compatible with project and industry carbon goals.
It is estimated that each square foot of building constructed with mass timber consumes, on average, 0.9 cubic feet of mass timber raw material. Each cubic foot of mass timber raw material is estimated to require 22.5 board feet (nominal) of lumber to produce. Doubling the number of buildings made from mass timber every 2 years between 2020 and 2034 equates to an estimated increase in lumber demand of 12.9 billion board feet by 2034*.As perspective, 2019 North American softwood lumber demand (the primary raw material used for producing mass timber) was estimated to be about 60 billion board feet. Thus, new softwood lumber demand arising directly from mass timber buildings in 2034 is estimated to be about a 21.5% increase over 2019 demand.
Carbon neutrality is an important goal, but the building industry can and should go further, and by 2034 can store more carbon than it emits if mass timber market saturation is achieved. Choosing sustainably harvested wood as a primary structural material significantly contributes to turning a building into a carbon store.a,b Quantifying the embodied carbon of wood products is complex, and it’s currently in a nascent and rapidly developing research phase. Forestry practices matter greatly in the carbon storage potential of wood, but it is not yet clear how to accurately measure or regulate carbon objectives. The Life Cycle Analysis (LCA) of a given building may choose to exclude wood decomposition in the carbon profile to better understand short-term (2050) impacts. Reuse potential is generally not factored in LCA models, nor is the global goal of reducing atmospheric carbon in the short term. a. There is an estimated 0.023 tons of carbon offset for every square foot of mass timber building instead of using steel and/or concrete. b. There is an estimated 0.0047 net tons of carbon sequestered by mass timber for every square foot of mass timber building.
Exposed wood surfaces support biophilic responses in building occupants, promoting health and productivity benefits in all building types. Demand for comfortable, healthy interior spaces drives a market for sustainably sourced wood buildings. Spaces that give occupants a “sense of place,” such as visible locally sourced wood, are correlated with environmentally conscious behavior, multiplying the benefits of a carbon-sequestering wood building.
In the near future, the carbon impact of any investment will factor into its market value. Sustainably harvested wood fits naturally into a Circular Carbon Economy. Mass timber consumers who support sustainable forestry practices and policies will push the wood market towards maximum carbon storage potential of forest products. The Life Cycle Analysis (LCA) of a given building may choose to include the 1-to-1 equivalent replanting that occurs in most North American forestry practices, or go further and pledge additional replanting to offset other carbon emitting building elements.