The Science Behind the Trust
Introduction by John Oster
I didn’t know it at the time, but my interest in the interaction between people and our biosphere took root in my childhood: by the time I entered high school in 1964, I had become a juvenile mad scientist. My father built a lab in the basement. My freshman science teacher guided my experiments with drosophila melanogaster, mus musculus, bell jars and vacuum pumps to explore the impacts of reduced atmospheric pressure and, later, increased radiation. By the late 1960’s that interest had turned into fascination with increasing carbon. And by the time I graduated from college in 1972, I was thoroughly hooked. It only took another fifty years to figure out what to do about it.
The fact of increasing atmospheric carbon is not up for debate. It has been long and well established, and that documentation is widely aviailable in libraries, on the internet, in research institutions, universities, and weather stations all over the world. Sometimes the facts get obscured or even called into question when people fall into an argument about whether the increasing carbon is “human-caused” or due to underlying natural cycles. There is sometimes a tendency to dismiss the facts because the debaters disagree over the “cause” of it all.
To put this simply, that horse has left the barn. The Carbon Forestry Trust does not care about the causes, we care only about doing something positive to mitigate and manage the effects. We applaud the many efforts underway to move society to Net Zero, the point at which atmospheric carbon will stop increasing. We are pretty sure, though, that what we should all aspire to is something more like Net Negative. In a very real sense, we need to lower the temperature.
I sincerely hope, and I imagine most people do, that somebody perfects clean nuclear fusion or invents a gizmo that will remove carbon from the atmosphere and permanently store it somewhere safe, without unforeseen consequences. I hope that this gizmo happens soon and can be scaled up so that it makes a real impact. We will need science and scientists there every step of the way, and they will need to be very, very good.
In the meantime though, we need to trust in the gizmo we already have. It’s been around for a long time and is uncommonly effective at turning atmospheric CO2 into life-giving oxygen while storing carbon long-term. The gizmo in question? The Tree.
The Science
Photosynthesis is the process by which green plants (and a few other organisms) feed themselves by using the energy of sunlight to convert carbon dioxide and water into nutrients in the form of sugars. As this happens, oxygen is released into the air. The sugars are used to build wood, leaves, branches, and roots.
Depending on the age and types of forest and the types of soil, it is also fair to say that much of any forest’s carbon sequestration actually takes place in the soil. This is evident from the presence of roots, leaf litter, and other organic detritus and is also a function of the ability of many soils to bind with carbon.
It becomes evident, when one considers the extremes, that the forests of North America in general and the northern and eastern United States in particular are among the best locations for carbon forestry in the Western Hemisphere. Tropical rainforests are frequently held up as the ideal carbon sinks, but the same conditions that promote prolific growth also lead to rapid decomposition. The great northern forests of Canada and Alaska sequester vast stores of carbon both in trees and permafrost, but they grow exceedingly slowly.
How Forests Store Carbon
In this 2020 essay, Penn State Extension scientists Calvin Norman and Melissa Kreye discuss the impact forests have on the carbon cycle and how they can be used to mitigate climate change.
The Trust has been aided in its research by the U.S. Forest Service, by NYS Department of Environmental Conservation Regional Foresters, by professional foresters, and by municipal foresters and arborists. The Forest Service has shared research that documents how much carbon various species sequester during their lifetimes. A seminal work on this subject by David Nowak et. al. was published in the Journal of Arboriculture in 2002 and is available here. Dr. Nowak and his colleagues quite properly focus their attention not only on which species sequester best but also on the varying degrees to which intensive management practices can reduce net sequestration. For example, consider the role of trucks, skidders, and chainsaws.
The regional and municipal foresters advise on those species which are indigenous to the sites being managed or considered by the Trust. The Trust seeks to propagate trees which are most likely to succeed where planted and will sequester carbon efficiently, be resistant to disease and wildlife browsing, and be desirable candidates for harvest and eventual use as lumber or as other long-lasting products.
According to the Arbor Day Foundation, the average mature tree absorbs more than 48 pounds of carbon per year. This is not universally accepted: other reports put the figure much lower or higher, however, it does appear to be mid-range. On an eight by ten-foot grid (juvenile trees), an acre would contain about 540 trees. For planning purposes only, the Trust assumes attrition due to browsing, drought, and other causes yielding a net result of 400 trees per acre. These numbers would indicate that an acre of such trees will sequester about ten tons of carbon per year (400 trees x 50 lbs./tree = 20,000 lbs. or 10 tons). Younger trees grow faster and absorb less carbon. Mature trees absorb more, grow slower, and over time become spaced father apart.
Scientists and foresters also point out that better management, or in many cases any management, of existing marginal woodlands can dramatically increase their ability to thrive and sequester effectively. Support for this approach appears in many places, including Chapter 15: Agriculture and Forestry of the New York Climate Action Council’s Scoping Plan, which is available here.
It is very evident from fieldwork that New York’s woodlands, most of which are owned privately, come in a variety of conditions. Some are rigorously and scrupulously managed. Some are not managed at all. Most fall somewhere in between, perhaps having been used as hunting camps or logged over for short-term financial gain at a long-term expense. The carbon storage provided by these lands would all increase measurably if sequestration forestry management were introduced.
The other side of the science, of course, is figuring out just what we humans do that adds carbon to the atmosphere, and by how much. The US Environmental Protection Agency maintains an e-tool online, available here to assist members of the public with household carbon footprint calculations. This is both an educational tool for families and a way for residential property owners and developers to approximate the carbon footprint of their projects.
The averages per person are fairly well known, but individual habits, household sizes, and geographic locations cause a wide variation in the actual results. Per the Nature Conservancy, the carbon footprint of residents of the United States works out to 16 tons per person, one of the highest averages in the world. Globally the figure is more like 4 tons.
Using the USEPA calculator, the Trust calculated the carbon footprint of a senior apartment complex consisting of 160 apartments, most of which are occupied by single elderly persons. The answer, per household, was 12,850 pounds per year per apartment. Multiplied by 160, that led to a total carbon footprint of 2,056,000 pounds, or 1,028 tons. To sequester 20% of this community’s carbon, multiply 1,028 tons by 20% to arrive at 205.6 tons. Then take 205.6 tons and divide by 10 tons per acre, which yields a requirement for 20.56, say 21 acres of dedicated, carbon sequestration forest.
The metrics evolve as the science progresses. The Trust fully expects that better data will be forthcoming and will in turn inform better decisions about where and what to plant, how to manage it, and how to measure and account for it. As we learn more, Trust priorities and activities will adjust accordingly and be reflected on these pages and elsewhere.