Fire-resistant trees????
Life imitating art a little too closely, ecological resilience, and how visionary tech can actually do good.
There’s no ignoring what’s happening on the west coast right now. Historic drought conditions and extreme temperatures (and some other events) through California, Oregon, and Washington have led to devastating wildfires currently affecting millions of people.
As they developed the visual palette for Blade Runner 2049, cinematographer Roger Deakins and director Denis Villeneuve referenced real-life environmental destruction from around the world: thick smog in Beijing, typhoons in the Philippines, dust storms in Sydney, and Los Angeles’ endless concrete landscape.
This week, the stunning visual results of Deakins and Villeneuve’s work broke from fiction to reality as San Francisco skies glowed vermilion and orange under a shroud of smoke. Draw your own conclusions as to how a fictitious future climatological collapse is now a reality every summer but, surprise, it’s not because consumers aren’t trying.
Here in Vancouver it’s not as orange, but we’re definitely cloaked in a blanket of smoke. It was just last weekend when the air was clear that I came across a patch of burned-out trees in Pacific Spirit Park. They were enormous, some over two metres across, and they gave off the most eerie vibes; it was as though a fire had ignited from within and left the charcoal-coated bark behind.
This is one of them. It big enough to wander around inside it.
The hollow shells prompted a question: Why did the insides of these trees succumb to flames but the outside survived?
One hypothesis that my research suggests is that the tree was stricken by root rot caused by Armillaria mellea, or, honey fungus. It rots the roots and heartwood core of trees, causing them to dry out and become susceptible to fire. Since only the insides are affected by Armillaria infection, it’s possible that with a lightning strike, fire could engulf the dead middle stuff and have trouble with bark if it’s damp enough. Not out of the question for a temperate rainforest.
That being said though, once a fire begins in a tree it’s probably gonna take the whole thing down without human intervention. Tree sap, held in the alive outer rings, is highly flammable (it’s how turpentine is made, remember) and in my extremely unprofessional opinion, typically ensures an inferno in most types of trees.
I’m gonna take it one step further. According to tree expert J. Casey Clapp (of the straight up joyous Ologies episode on dendrology), coastal redwoods are insect-resistant, rot-resistant, and their suuuuper dense, feet-thick bark makes them fire-resistant as well. He says it’s not uncommon to find hollowed-out redwoods re-sprouting after a fire “because they can sprout from any place that still has functionality down to the roots.” Cool!
The National Forest Foundation agrees:
Trees in fire-prone areas develop thicker bark, in part, because thick bark does not catch fire or burn easily. It also protects the inside of the trunk, the living tissues that transport water and nutrients, from heat damage during high-frequency, low-intensity fires. Ponderosa pine (Pinus ponderosa, also commonly known as the bull pine, blackjack pine or western yellow pine) is a great example. This signature tree in the western United States has a thick and flaky bark, sometimes compared to pieces of a jigsaw puzzle, which perfectly withstands a low-intensity, surface fire. The species also drops lower branches as the trees grow older, which helps prevent fire from climbing up and burning the green needles higher up the tree.
So way back when the fire tried to take these big ol’ trees down, it’s possible that the dense bark prevented the flames from destroying the entire tree structure. It was forced to leave the outer shell behind, just in case there was a chance of regrowth.
So there’s an answer, maybe! And a testament to some real evolutionary advantages.
Near the end of his episode when Casey and Alie are talking about the future of forestry, he mentions some incredible developments in the construction industry that have come out of these trees’ robust characteristics. Here’s the transcript of that moment, edited for length and clarity:
Casey: We’re doing things right now with trees, it’s called cross-laminated timber, CLT. It is gonna be the future, and I’m absolutely sure. They’re doing it in Germany, and we’re just now in Oregon getting a couple mills on board to do it.
Basically think really thick plywood, where you have boards going left and right, then you have ‘em turn 90 degrees and they’re going that direction. And you’re just doing this over and over until you get this big thick piece of panel, and then you can cut that into whatever shape you want and put it together like Legos.
Literally, they said if you hear hammers and nails when they’re building this type of structure, then something went wrong. Because they just sort of fit in together, and then they’re more fire-resistant, this is the funniest thing, because it’s wood.
Alie’s aside: So this new type of lumber is too dense to burn. Now, it’s also what’s called a carbon sink, because it traps carbon dioxide and keeps it there, which helps counter climate change and global warming, which is necessary if we don’t want to be swallowed by boiling oceans. [ding!]
Casey: So it should be the future, I’m really looking forward to it. Ideally.
Alie: That’s really optimistic, ‘cause I wasn’t sure what the future was gonna be, and this is good to know.
Casey: Yeah. I hope it is, I hope it is, because if we can get it to the extent where almost all of our buildings are now timber-framed again, we can make sure that all of our trees are grown properly and under certain conditions. Wood is naturally good at moving, so you don’t have to worry about the tensile strength, everything’s already built into the fiber itself.
So CLT applications in building construction might be an option to increase fire resistance in structures at risk for wildfire damage. Plus, it’s a huge bonus to be able to build carbon sinks in urban areas to mitigate greenhouse gas emissions. Talk about a revolutionary green technology. CLT has the potential to address two or more huge infrastructure and climate change-related concerns without excluding or adversely impacting populations who need it most (AHEM, ELON MUSK). Points for that, but I want to know more.
What I’m curious about specifically is how to ensure sustainable logging practices if CLT really is the wave of the future. It’s on the list for another edition.
That’s it! Go gently hug a tree, nerds! They’re mysterious and majestic and so important to our planet’s survival!
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