Forest Carbon Coalition – Science Synthesis

Climate smart forest practices – what are they and what are the economic benefits to communities, workers, and landowners?

The term ‘climate smart forestry’ has been widely embraced by federal, state and local governments as a catch-all phrase to describe more climate sensitive forest management alternatives to business-as-usual practices. Ideally, a climate smart practice would simultaneously increase carbon stored on the land, reduce greenhouse gas emissions, increase carbon sequestration and improve the resiliency of landscapes to climate change relative to BAU. Afforestation, reforestation, proforestation (letting forests grow to their full ecological potential), alternatives to clearcutting, long harvest rotations and restoring timber plantations back to real forests are specific practices that can meet one or more of these criteria.

However, most forms of logging – no matter how carefully they are planned – adversely affect climate change by generating greenhouse gas emissions and increasing fire risk, so their inclusion on the list of climate smart practices is disputed. Nonetheless, compared to conventional, short rotation clearcutting, practices like variable density thinning and long rotations minimize those climate risks while generating income for landowners, increasing forest cover and structural complexity of stands and restoring a wide range of ecosystem service benefits – like clean water, fish and game – for local communities. In addition, letting trees grow longer, at least to the age when growth is maximized (typically 80-130 years) before they are cut for timber yields more volume per acre and a price premium for older, fine-grained wood.

Key research on climate smart forest practices:

Tappeiner, J., Adams, D., Montgomery, C., Maguire, D., 2022. Growth of managed older Douglas-fir stands: implications of the Black Rock thinning trial in the Coast Range of Western Oregon. Journal of Forestry, 2022, 282-288.

Link: https://doi.org/10.1093/jofore/fvab063

Summary: The Black Rock thinning project is intended to demonstrate that silvicultural interventions – here, thinning and long rotations –  can help restore dense, young timber plantations back into structurally complex older forests. The authors measured tree growth after thinning that began in 1958 at an average stand age of 50. They also completed a financial analysis that considered how thinning revenues could offset the opportunity costs of extended rotations.

Key excerpts:

  • “Thinnings at several intensities at total stand age of roughly 50 years effectively reset stand growth patterns. With quadratic mean diameters in thinned plots up to 40% higher than those of unthinned controls, thinned plot mean annual increments (MAIs) and periodic annual increments continue to rise 55 years after thinning, with the peak in board foot and cubic foot MAI apparently still decades in the future.”
  • “Financial analysis of the opportunity costs of extending rotations to 100 years indicates that some thinning treatments can reduce opportunity costs by up to half at a 6% discount rate.”
  • Mid rotation thinning of dense young plantations is “compatible with growing trees with large diameter stems, large branches, and large crowns.”
  • Such thinning also reduces fuel accumulation by “lowering mortality rates of stems less than 60 years old and slowing the rate of crown recession, branch mortality, and branch litterfall.”

Doelman, J.C., Stehfest, E., van Vuuren, D.P., et al., 2019. Afforestation for climate change mitigation: potentials, risks and tradeoffs. Global Change Biology 26(3): 1576-1591.

Link: https://doi.org/10.1111/gcb.14887

Summary: The global economic potential of afforestation was assessed with the IMAGE 3.0 integrated assessment model framework. The effects of afforestation on food supply is also addressed under increasingly ambitious climate targets.

Key excerpts:

  • “Afforestation has a mitigation potential of 4.9 GtCO2/year at 200 US$/tCO2 in 2050 leading to large-scale application in an SSP2 scenario aiming for 2°C (410 GtCO2 cumulative up to 2100).”
  • “Afforestation reduces the overall costs of mitigation policy. However, it may lead to lower mitigation ambition and lock-in situations in other sectors.”
  • “Afforestation also requires large amounts of land (up to 1,100 Mha) leading to large reductions in agricultural land. The increased competition for land could lead to higher food prices and an increased population at risk of hunger.”

Moomaw, W.R., Masino, S.A., Faison, E.K., 2019. Intact forests in the United States: proforestation mitigates climate change and serves the greatest good. Front. For. Glob. Change, 11 June 2019.

Link: https://doi.org/10.3389/ffgc.2019.00027

Summary: The authors coin the term ‘proforestation’ – growing existing forests intact to their ecological potential – and quantify the role of this climate smart practice in mitigating climate change and generating a wide range of ecosystem service benefits.

Key excerpts:

  • “The IPCC identifies reforestationand afforestation as important strategies to increase negative emissions, but they face significant challenges: afforestation requires an enormous amount of additional land, and neither strategy can remove sufficient carbon by growing young trees during the critical next decade(s).”
  • “In contrast, growing existing forests intact to their ecological potential—termed proforestation—is a more effective, immediate, and low-cost approach that could be mobilized across suitable forests of all types.”
  • “Proforestation serves the greatest public good by maximizing co-benefits such as nature-based biological carbon sequestration and unparalleled ecosystem services such as biodiversity enhancement, water and air quality, flood and erosion control, public health benefits, low impact recreation, and scenic beauty.”