I have to say, I really enjoy the metaphor of a Jenga tower, for the way the world is going. Blocks are being removed to build the top to new heights, with no concern for the overall instability being created. Sea level rise, chemical pollution, habitat destruction, extreme weather, fascism, decaying capitalism, new diseases – things are feeling pretty unstable right now. To extend the metaphor, a lot of what we are trying to do is to add blocks at the bottom to re-stabilize things. Some of that is social – adding new “stabilizers” like universal healthcare, free mass transit, reliable access to power, housing, food, and water, and so on. And some of it, as we so often discuss here, is ecological – actively working to add new “blocks” through things like rewilding, while also working to prevent the blocks that remain from being taken like so many others to add to the top.
Specifically, to disentangle ourselves from the metaphor, we need to preserve existing, and especially old wilderness. This is not some kind of “it was better before humans messed everything up” nostalgia or something. As I’ve written about before, ancient trees bring resources and stability that younger forests simply lack. The research we’re looking at today underscores the importance of old-growth trees when it comes to drought resistance:
A new analysis of more than 20,000 trees on five continents shows that old-growth trees are more drought tolerant than younger trees in the forest canopy and may be better able to withstand future climate extremes.
The findings highlight the importance of preserving the world’s remaining old-growth forests, which are biodiversity strongholds that store vast amounts of planet-warming carbon, according to University of Michigan forest ecologist Tsun Fung (Tom) Au, a postdoctoral fellow at the Institute for Global Change Biology.
“The number of old-growth forests on the planet is declining, while drought is predicted to be more frequent and more intense in the future,” said Au, lead author of the study published online Dec. 1 in the journal Nature Climate Change.
“Given their high resistance to drought and their exceptional carbon storage capacity, conservation of older trees in the upper canopy should be the top priority from a climate mitigation perspective.”
The researchers also found that younger trees in the upper canopy—if they manage to survive drought—showed greater resilience, defined as the ability to return to pre-drought growth rates.
While deforestation, selective logging and other threats have led to the global decline of old-growth forests, subsequent reforestation—either through natural succession or through tree planting—has led to forests dominated by increasingly younger trees.
For example, the area covered by younger trees (<140 years old) in the upper canopy layer of temperate forests worldwide already far exceeds the area covered by older trees. As forest demographics continue to shift, younger trees are expected to play an increasingly important role in carbon sequestration and ecosystem functioning.
“Our findings—that older trees in the upper canopy are more drought tolerant, while younger trees in the upper canopy are more drought resilient—have important implications for future carbon storage in forests,” Au said.
“These results imply that in the short term, drought’s impact on forests may be severe due to the prevalence of younger trees and their greater sensitivity to drought. But in the long run, those younger trees have a greater ability to recover from drought, which could be beneficial to the carbon stock.”
It’s good that younger trees are able to bounce back, and it shows the validity of re-foresting, but the unique properties of old-growth forests are another reason why, as I said last time I wrote about this, it’s important to defend what we have. The work that land defenders are doing in Atlanta, and other places around the world, benefits all of us, even if we never, ever actually walk under those trees, or have to deal with the cops that want to cut them down. When it comes to ecosystems on the other side of the world from you, think of them like your city’s water treatment plant, or the power plant, miles and miles away, that’s generating your electricity. The way those ecosystems affect the air and water does actually impact your life, albeit indirectly.
The one upside of inheriting a world that’s been ravaged by greed for the last couple centuries, is that there are so many ways we could start improving things. Some of that can be done directly, right now, and I have immense respect for those who put their bodies between our environment and destruction, as well as those that provide them with material support. It’s also worth noting that in some cases, their work puts them in clear, immediate danger, especially when they’re indigenous.
We’ve been fortunate, in that the “Jenga tower” of our world had a lot of blocks to remove, so it’s taken a while, for the instability to become obvious. It’s also very good that, while much has been lost, there’s still a fair amount of land out there that’s relatively “untouched”, in addition to the various “younger” ecosystems. It sometimes bugs me that I keep coming back to the need for political change, but at the end of the day, most of the big problems in the world lead back to our political and economic status quo. Support land back, support land and water protectors, and do what you can to build collective power and move other people to the left. We’re blessed with an abundance of opportunities for making the world better, but a lot of them are time-limited, so there’s no time to lose!
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