Liz HicksAug 5, 2023
David Ho

Is everyone on the same page that old-growth forests sequester much more carbon than younger forests?

So it makes more sense to focus on not cutting down trees rather than planting new trees since it takes two to three decades for trees to reach full maturity, if they survive.

Aug 5, 2023 at 9:37amWeb
Show threadJack ScrivenAug 5, 2023
@davidho I'm no expert, but would think we need both? Just protecting existing reduced forest will not be enough?
Show threadGeneration ZenAug 5, 2023
@davidho fire laughing at your tree planting carbon offsets
Show threadMartinAug 5, 2023
@Person @davidho Indeed, plant with scale like a deity, it will just burn and re-release any carbon captured. The time to think that this is a good pathway forward instead of just leaving it in the ground, is behind us
Show threadcultdevDec 10, 2023
@martintheg @Person @davidho true, though still no reason to eliminate the good tree soldiers we have now, and whose benefit we desperately need. but yeah trees alone will never solve the problem, not even close
Show threadBigDAug 5, 2023
@davidho Similar to the human race I suppose.
Depends on whether belief in the future is enough to motivate new life.
Or do we just hope the old will hang on long enough.
It eventually dies though.
Everything needs replaced if we want our world to carry on.
Show threadGabriel PettierAug 5, 2023
@davidho cutting down a whole forest is well understood to be a bad idea i think (or at least, hope), but cutting a tree that has reached adult size (or slowed down growth) and replacing it with a younger one makes sense, right?
Show threadDavid Wicks šŸ‡µšŸ‡øAug 5, 2023
@tshirtman @davidho Mature trees sequester way more carbon than young ones. They may not look like it to the casual observer but if you think about how much bigger a mature tree is, an extra layer of growth around its entirety is more than a young tree can manage. Also they have significantly more leaves, when these fall much of the carbon is sequestered in the forest soils.
Show threadKonstantin WeddigeAug 5, 2023

@tshirtman @davidho it is a misconception, that trees reach "adult size" and stop growing. Trees bind up to 50% of their total carbon content in the last quarter of their lifetime.

The idea, that trees grow faster in their "youth" seems plausible, because the growth happens in a way that is easier to perceive my humans (smaller than a human -> bigger than a human), and was never really questioned, because it's convenient for forestry. But it's wrong.

Show threadKonstantin WeddigeAug 5, 2023
@tshirtman @davidho Source: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181187
The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname

The worldā€™s forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growthā€”periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.

Show threadGabriel PettierAug 5, 2023
Thank you for clearing my misconception @David_Wicks @MahTeo and in particular @weddige for providing a source @davidho
Show threadCarl MyrlandAug 5, 2023
@davidho
There's another point to this, in terms of biodiversity. Old forests (100+ years) have other (and more) organisms thriving there than young forests, so cutting down forests and replanting is also damaging to diversity. In Norway we only have something like 20-30% left of the old forests we had in ~1950. Also industrial forests are more or less monocultures, where other trees and plants don't stand much of a chance..
Show threadSyulangAug 5, 2023
@cmyrland @davidho
This.
This.
This.
Show threadSyulangAug 5, 2023
@davidho it takes 4000 years for a fully fledged primary tropical/subtropical rainforest to completely regenerate. Deforestation is ecocide. It is never OK to log or "clear" old growth forest.
Show threadLiam LanganAug 5, 2023

@davidho https://www.nature.com/articles/nature12914

https://www.google.com/amp/s/theconversation.com/amp/big-old-trees-grow-faster-making-them-vital-carbon-absorbers-22104

Rate of tree carbon accumulation increases continuously with tree size - Nature

A global analysis shows that for most tree species the largest trees are the fastest-growing trees, a finding that resolves conflicting assumptions about tree growth and that has implications for understanding forest carbon dynamics, resource allocation trade-offs within trees and plant senescence.

Nature
Show threadMaartenDec 11, 2023

@My_plants_dance @davidho This paper is about growth rates of individual trees and notes in the abstract that ā€œproductivityā€ (i.e. carbon fixing) of *stands* (forests) does decline with age.

Thereā€™s lots of decay going on in old growth forests that causes release of carbon. Itā€™s a complex picture.

(All that said, Iā€™m fully in favor of not cutting down any old growth anywhere. We have plenty of tree farms.)

Show threadGatekeeper..Aug 5, 2023
@davidho
When you want to know when the wheel came off the wagon in America.
Show threadBerkAug 5, 2023
@davidho the forestry industry argues the opposite (erroneously), so now we have sustainability certification schemes like FSC that certify old growth logging as sustainable ā€˜if required for economic reasonsā€™.
Show threadEsme CiredutempsAug 5, 2023
@davidho
*Why not both* meme
Show threadarthurgesslerAug 5, 2023
@davidho I do in principle agree - but when it comes to replacement of steel and concrete with extremely high CO2 footprints, wood is an important alternative - take out stems from forests in a sustainable way (selective felling no clear cuts) use the timber in a cascading manner - building after 150 years recycle to wood based materials and after these are done burn it - and at the same time let the forest regenerate - you can then sequester and store (virtually) more C per haā€¦
Show threadarthurgesslerAug 5, 2023
@davidho ā€¦ and replace high CO2 footprint materials - heterogeneous forests (by sustainable management) harbor often higher diversity than old stands - at least in temperate zones - still we need untouched forests and the 20% undisturbed forest goal for Europe is important- I think we need both and in a good balance!
Show threadmartin lentink šŸ‡ŖšŸ‡ŗ šŸ‡ŗšŸ‡¦šŸ“ŽAug 5, 2023
@davidho We need to do both. Not cutiing down old trees AND planting many young trees.
Show threadAnnika BackstromAug 5, 2023
@davidho we're chopping down old growth trees, planting new trees as carbon offsets, and then those trees are burning down in part due to climate change
Show threadBeach-n-BrewAug 5, 2023
@davidho Both actions are important
Show threadMatteo GavagninAug 5, 2023
@davidho @takvera old growth forests or single trees. Difference is key.
Show threadsheislaurenceAug 5, 2023
@davidho we wouldnā€™t need #treeplanting if we didnā€™t cut down #forests in the first place: forests & ancient #woods naturally regenerate, thank you very much. As for the weakling shit dried-up branches #reforestation projects brandish as actual #trees, surprise surprise, HALF die within 5 years and those that survive are earmarked for #timber. There is actually NO measured goal of tree survival or number of mature trees in those projects. #stopthebullshit #greenwashing https://ig.ft.com/one-trillion-trees/
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Show threadPhil SturgeonAug 6, 2023

@davidho some studies argue old does more, some argue young does more, depends on the soil, species, and a million other factors.

Focusing on the trees is the bit where people go wrong. Effective ecosystems are usually brilliant at sequestering carbon, and the worst types of plantations are usually pretty barren.

Anyway, itā€™s different people working on it all. Iā€™m creating woodlands in the U.K. and thereā€™s obviously very little I can do about Brazilian deforestation.

Show threadPhoenixSerenityAug 24, 2023

@davidho Our old growth ancient forests are the 2nd largest carbon sinks - after kelp sea forests. Both are under ongoing ecocidal threats.

Although treeplanting is good, if old growth is clearcut - billions of saplings won't make much of a difference. It's foolish to destroy our biggest carbon sinks. No amount of money can replace Mother Earth's largest lungs of life.

Show threadMaxilo OveritAug 24, 2023

@davidho

"Oh, so you want to cut down one mature tree? Well, you're going to have to set aside 20 acres and plant a dozen species of trees with a land contract that never allows trees to be cut from that land. Ever. And that's at your expense."

"Oh, so you want to cut down an acre of such trees? LOL, I don't think you can afford that. How about you move on, Mister Company, and peddle your eco-aware live tree cutting business on some other planet?"

Show threadPatrickMeyfroidtDec 10, 2023
@davidho yes.
Show threadHoward GreenDec 11, 2023
@davidho And, of course, it' s much better for biodiversity. Old trees provide home for literally thousands of species. New planting can be done well. Too much is still practically monoculture.