A pine can live for 800 years, it can stand dead for another 300 years, and continue to store carbon 300 more years as fallen wood. There’s a lot of new research pointing the direction that really old forests are best both for sequestering and storing carbon. How can we make that a viable economical option? Here I republish a previous Twitter thread.
I have been following Timo Pukkalas forest research for a number of years. In an recent research paper he applies simulations to test out the best strategies for storing carbon in trees: let them be. After an initial thinning regime to adapt the forest, the 300 year scenation wins. ”Carbon forestry is surprising” he called the paper: https://www.researchgate.net/publication/323664549_Carbon_forestry_is_surprising
”Maximizing carbon balance led to low cutting level with all three planning horizons. Depending on the time span, the carbon balance of these schedules was 2 to 3.5 times higher than in the plan that maximizes net present value. It was not optimal to commence cuttings when the carbon pool of living biomass and dead organic matter stopped increasing after 150–200 year”
”Letting many mature trees to die was a better strategy than harvesting them when the aim was to maximize the long-term carbon balance of boreal Fennoscandian forest. The reason for this conclusion was that large dead trees are better carbon stores than harvested trees. To alter this outcome, a higher proportion of harvested trees should be used for products in which carbon is stored for long time.”
”The results of this study suggest that, when the long-term carbon balance of forestry is maximized, harvesting level should be low. This leads to mortality and accumulation of carbon in dead trees. It was concluded that the main reason for this result is that, in boreal forests, large dead trees are often better carbon stores than harvested trees. The carbon balance of a dead tree may be better than that of a harvested tree, even when the avoided emissions from fossil fuels are included in the carbon balance of harvested trees”
This is also supported by US research:
”Permanently protecting large, mature forests is a faster and cheaper way to stabilise Earth’s climate than complex carbon capture and storage schemes, and more effective than planting new trees”
Existing forests can store 2x:
”Forests pull about one-third of all human-caused carbon dioxide emissions from the atmosphere each year. Researchers have calculated that ending deforestation and allowing mature forests to keep growing could enable forests to take up twice as much carbon.”
”More than half of US forested lands are privately owned, so strategic forest carbon reserves should be established on both public and private lands. The challenge is paying for them, which will require a major shift in government and societal priorities.”
Also cited in this swedish post by @Natursidan: https://www.natursidan.se/nyheter/skydda-gamla-skogar-snabbt-och-billigt-satt-att-lagra-kol/
Growing existing forests intact to their ecological potential even has a name: proforestation. In this thorough paper they argue https://www.frontiersin.org/articles/10.3389/ffgc.2019.00027/full
”Proforestation produces natural forests as maximal carbon sinks of diverse species (while supporting and accruing additional benefits of intact forests) and can reduce significantly and immediately the amount of forest carbon lost to non-essential management.”
Boreal forest are very suitable for proforestation:
”Forests in temperate zones such as in the Eastern U.S. have a particularly high untapped capacity for carbon storage and sequestration because of high growth and low decay rates”
Sweden is also ripe for proforestation, challenging the exiting forestry regime. As far as I know there is zero projects in connecting growing forests to carbon negativity and carbon pricing in Sweden.
But how could long term growth and storages in our forests be made economically viable? That’s the key question. What if there was a market to rent stored carbon?