Reforestation to Combat Climate Change
Not all strategies are equal in our fight to limit atmospheric carbon. New technologies for industrial carbon capture make headlines every few years, but no industrial technique comes with as many secondary benefits as natural climate solutions. Natural climate solutions (NCS) include conservation, restoration, and improved land management practices that reduce emissions and increase natural carbon sequestration and storage. Each NCS practice reduces atmospheric carbon but reforestation has the greatest potential to help us keep global warming below 2ᐤC (1). Tree planting is one of the most intuitive and popular tools we have, so why aren’t reforestation projects playing a larger role in today’s voluntary carbon markets?
Forests are ideal systems for carbon sequestration and storage. Plants capture carbon as biomass and trees, especially young trees, produce a lot of biomass. In the highly productive forests of the Pacific Northwest, an acre of mature forest can hold nearly 135 tonnes C (495 tonnes CO2 atmospheric equivalent) per hectare in living and dead trees (2). What distinguishes reforestation and afforestation projects (AAR) from improved forest management (IFM) projects is the difference in added carbon. Because IFM project baselines are still forestland, the carbon added by improved management is only a portion of the forest’s total carbon stores. In contrast, reforestation projects convert degraded or deforested land with little carbon benefit into potentially massive carbon sinks.
There are a wide variety of conditions where carbon-additional tree planting projects are appropriate. In the wake of wildfire, large areas are often never replanted and lands are left deforested or understocked. Widespread clearing of native forests to create farmland and pasture have resulted in many abandoned or fallow fields that are overgrown with invasive species. Areas that were cleared for mining are often so compacted and degraded that after the land is left to recover, trees are unable to establish without intervention. The abundance of suitable reforestation sites is one of the main reasons they have so much potential in the global fight against climate change. The primary need to restore tree cover is investment.
Unfortunately, high capital costs are frequently a major obstacle to reforestation for landowners whose funding will only be recovered after relatively slow tree growth generates timber returns. Even valuing climate and carbon benefit does not always make an investment attractive enough. Avoided-conversion and improved forest management projects often generate significant carbon volumes in the first few years and can thus recover initial capital expenses quickly. Reforestation projects on the other hand, require a large investment in seedlings, site preparation, planting, and maintenance until the forest is established. Even if everything is done correctly, it can be hard to predict how many of the planted seedlings will survive their first few years. This in combination with the uncertainty of a young and evolving carbon market naturally pushes investors towards projects with faster returns and short-term certainty. For this reason, there have been very few reforestation projects supported with climate and carbon investments in the US to date.
Over the next few years, The Climate Trust will address this challenge by building on its history of climate solution firsts to pilot and demonstrate how valuing the climate benefit of reforestation can drive forest restoration across the country. Our team will develop climate-smart reforestation demonstration projects in a range of forest types, across timber markets, and with a variety of landowners. We will share lessons learned, challenges, and opportunities with the hope of advancing a community of practice and market infrastructure to support rapid scaling of this critical climate change solution.
Griscom et al. 2019. Available at: https://www.pnas.org/doi/10.
Woodbury, P. B., J. E. Smith, and L. S. Heath. 2007b. Carbon sequestration in the US forest sector from 1990 to 2010. Forest Ecology and Management 241:14-27 nrs_2007_woodbury_001.pdf (usda.gov)