As the need to address climate change grows more urgent, policymakers, businesses, and others are seeking innovative approaches to remove carbon dioxide emissions from the atmosphere and decarbonize hard-to-abate sectors. Forests can play a role in reducing atmospheric carbon. However, there is disagreement over whether forests are most effective in reducing carbon emissions when left alone versus managed for sustainable harvesting and wood product production. Cross-laminated timber is at the forefront of the mass timber movement, which is enabling designers, engineers, and other stakeholders to build taller wood buildings. Several recent studies have shown that substituting mass timber for steel and concrete in mid-rise buildings can reduce the emissions associated with manufacturing, transporting, and installing building materials by 13%-26.5%. However, the prospect of increased utilization of wood products as a climate solution also raises questions about the impact of increased demand for wood on forest carbon stocks, on forest condition, and on the provision of the many other critical social and environmental benefits that healthy forests can provide. A holistic assessment of the total climate impact of forest product demand across product substitution, carbon storage in materials, current and future forest carbon stock, and forest area and condition is challenging, but it is important to understand the impact of increased mass timber utilization on forests and climate, and therefore also on which safeguards might be necessary to ensure positive outcomes. To thus assess the potential impacts, both positive and negative, of greater mass timber utilization on forests ecosystems and emissions associated with the built environment, The Nature Conservancy (TNC) initiated a global mass timber impact assessment (GMTIA), a five-part, highly collaborative research program focused on understanding the potential benefits and risks of increased demand for mass timber products on forests and identifying appropriate safeguards to ensure positive outcomes.

The capacity of forests to store carbon, combined with time-tested approaches to managing forests, make forests a useful tool for atmospheric carbon mitigation. The primary goals of this study are to determine the amount of unrealized mitigation available from Improved Forest Management (IFM) in the Acadian Forest of New England in the northeastern U.S., and to demonstrate how this mitigation can feasibly be attained. This study used the Forest Vegetation Simulator (FVS) to model the impacts of IFM practices articulated by the New England Forestry Foundation on carbon storage in the Acadian Forest. Our results, together with empirical data from well-managed forests, show that if the modeled improved management is employed on privately owned timberland across the Acadian Forest of New England, carbon storage could be increased by 488 Tg CO₂e. Our financial modeling shows that IFM could be funded in this region by combining income from carbon markets with the philanthropic funding of conservation easements, timber revenues, and capital investments from private investors who prioritize social and economic goals alongside financial returns. This study adds to the body of evidence from around the world that the potential for managed forests to contribute to climate change mitigation has not been fully realized.

To estimate the potential and realized carbon emission reductions from implementation of reduced-impact logging (RIL) in Indonesia, we compiled logging emissions data from 15 concessions in Kalimantan and 10 from the Papuan provinces. Committed emissions data were collected for harvested timber as well as from collateral damage caused by felling, skidding, and clearing for haul roads and log yards. Emissions expressed as mean ± standard error per cubic meter of timber harvested, per area harvested, and per Mg of timber harvested (i.e., the ‘Carbon Impact Factor’) were 1.30 ± 0.15 Mg C m⁻³, 27.52 ± 4.44 Mg C ha⁻¹, and 6.88 ± 0.84 Mg Mg⁻¹, respectively. Among the sampled concessions, felling, hauling, and skidding caused 18–86%, 2–48%, and 6–75% of these emissions, respectively. Potential emission reductions calculated as the difference between observed emissions and those of the five best-performing concessions are 0.67 ± 0.15 Mg C m⁻³, 21.11 ± 4.38 Mg C ha⁻¹, and 4.20 ± 0.83 Mg Mg⁻¹, which represents reductions of 51%, 76%, and 61%, respectively. Extrapolating these estimates to all of Indonesia using average log production data from 2018 to 2021 results in an estimated annual emissions reduction of 14.47 Tg CO₂ from full adoption of RIL, which is 2.9% of Indonesia’s nationally determined contribution (NDC) from the forestry sector.