Intact forests in the United States: proforestation mitigates climate change and serves the greatest good, Moomaw 2019

The concept of “proforestation” presented here means letting existing forests continue to grow and reach their full ecological potential. Due to intensive management practices, most existing forests sequester carbon at only half (or less) of their potential rate. In addition to storing (embodying) more carbon than their smaller counterparts, large trees also sequester carbon at a faster rate. For example, “Each year a single tree that is 100 cm in diameter adds the equivalent biomass of an entire 10-20 cm diameter tree, further underscoring the role of large trees” [Moomaw 2019: 4]. Imagine, reader, that every year you planted a whole new medium-sized tree – that’s essentially what large trees are doing.

Much of Maine’s forests have been harvested continuously for 200 years and have a carbon density less than one-third of the forests of Southern Vermont and New Hampshire, Northwestern Connecticut and Western Massachusetts – a region that has not been significantly harvested over the past 75-150 years. …

Ecosystem services accrue as forests age for centuries. Far from plateauing in terms of carbon sequestration (or added wood) at a relatively young age as was long believed, older forests (e.g., >200 years of age without intervention) contain a variety of habitats, typically continue to sequester additional carbon for many decades or even centuries, and sequester significantly more carbon than younger and managed stands [Moomaw 2019: 5].

Because existing forests are already sequestering carbon, and will continue at an increasing rate as tree size grows, the author argues that proforestation is a more effective immediate solution than either reforestation (planting new trees where they had been cleared for agriculture, etc.) or afforestation (planting trees in new places), though these other two approaches are important for longer term ecosystem function. Moomaw et al. argue that the urgency of removing CO2 makes it imperative to keep existing forests growing.

Globally, existing forests only store approximately half of their potential due to past and present management, and many existing forests are capable of immediate and even more extensive growth for many decades. During the timeframe while seedlings planted for afforestation and reforestation are growing (yet will never achieve the carbon density of an intact forest), proforestation is a safe, highly effective, immediate natural solution that does not rely on uncertain discounted future benefits inherent in other options [Moomaw 2019: 7].

Furthermore, existing, older forests are critical habitats for threatened wildlife, even small intact woods.

Forest bird guilds also benefit from small intact forests in urban landscapes relative to unprotected matrix forests. Several bird species in the U.S. that are globally threatened – including the wood thrush, cerulean warbler, marbled murrelet, and spotted owl are, in part, dependent on intact, older forests with large trees [Moomaw 2019: 5].

In sum, proforestation provides the most effective solution to dual global crises – climate change and biodiversity loss. It is the only practical, rapid, economical, and effective means for atmospheric CDR [carbon dioxide removal] among the multiple options that have been proposed because it removes more atmospheric carbon dioxide in the immediate future and continues to sequester it long-term. Proforestation will increase the diversity of many groups of organisms and provide numerous additional and important ecosystem services. While multiple strategies will be needed to address global environmental crises, proforestation is a very low-cost option for increasing carbon sequestration that does not require additional land beyond what is already forested and provides new forest related jobs and opportunities along with a wide array of quantifiable ecosystem services, including human health [Moomaw 2019: 8].