How much land use is a trillion trees for the afforestation slider?
When I presented last weekend - we simulated a world the "news" regarding one trillion trees and CO2 sequestration were being thrown out as a "solution."
Some one other than me (best scenario!) pointed out that this does nothing to the energy demand chart - (chart on the left.) So En-Roads led the conversation to "ya really need to STOP pumping GHG into the atmosphere, too ...."
One more thing that occurred to me, this is a fairly dense forest. Where my trees are 10 feet apart, the crowns (leaf area) are packed together. This, along with root competetion, limits growth, which limits the amount of CO2 sequestered.
Laura : Your estimates look good.
There's a lot of smoke and mirrors in this climate denier's solution. Given the estimates from the model, I think that the audience can figure this one out.
I looked at some other articles regarding the "Trillion Tree Planting" campaign assumes that 600 Billion trees will last until maturity so we are perhaps getting close to the En-Roads maximum setting for tree cover.
Still not a big effect on reducing the CO2 in the air as you indicated, Mark. -0.2 Deg C.
Thank you, Mark!
You did some heavy lifting with the calcs!
To boil it to relatable terms, to plant one trillion trees would take 1 billion hectares of land which is approximately the land mass of the entire United States including Alaska and Hawaii!
USA Land Mass (including Alaska & Hawaii) =
Is that about right?
Thank you again, Laura
So, I'm taking a stab at this from an article I read here: https://reason.com/2020/02/13/republican-lawmakers-introduce-trillion-trees-act-to-combat-climate-change/ and the Science article.
Reading further in other places, there are optimal spacing for trees, and, of course, the amount of land used depends on how far apart you space the trees. Optimal spacing of anywhere from 10 (small trees) to 50 feet (oaks), with tree separation up to 100 feet, depending on how the forest will look.
This article claims 400 tress per acre, which is trees spaced 10 feet apart, or 20x20. That's 988 trees/hectare. To make the math easy, let's call it 1000 trees/hectare. So, 1 trillion trees divided by 1000 trees/hectare = 1 billion hectares.
According to the Science article, "there is room for an extra 0.9 billion hectares of canopy cover".
In En-ROADS terms, you can go to afforestation detail and view the graph on "Land for Carbon Dioxide Removal" . The highest I could get to was 0.7 billion hectars by 2100. That only does 700 Billion trees. That changed a scenario I was working on about -0.2 C.