How Did Iceland Solve Their 1,000 Year Deforestation Problem?

追加: 2026-06-01

[00:00:00]This is Iceland. Black gravel to the horizon, dust lifting off the ground, and not a single tree in sight.

[00:00:07]It looks like the surface of a dead planet. It didn't start this way.

[00:00:12]1,100 years ago, this exact ground was forest, birch running from the mountain tops down to the sea, covering up to 40% of the island.

[00:00:23]Then the Vikings landed and cut almost all of it down.

[00:00:27]The wind carried the bare soil out to sea, and a green island slowly turned into a cold desert.

[00:00:34]Now, Icelanders are trying to drag that forest back by hand, with fences, with purple flowers from Alaska, by planting trees in a ring around a live volcano.

[00:00:47]So, how do you rebuild a forest erased a thousand years ago?

[00:00:51]But before we can answer that, you have to first understand how an entire country lost its forests in the first place. See, Iceland sits right here, just under the Arctic Circle, alone in the North Atlantic.

[00:01:05]Built out of nothing but volcanoes, it's cold, windy, and dark half the year. You look at it and assume it was always bare rock, but it wasn't. When the first people stepped off their boats, birch grew thick right down to the edge of the water. And that's important because birch is the only single kind of tree that can build a forest in Iceland.

[00:01:29]Yes, this downy birch that's short, stubborn, and 10 to 13 m tall on its best day.

[00:01:36]Everything else is a thin scatter of rowan [snorts] and willow.

[00:01:40]So, where did all the birch go? Well, for that, we'll have to go back in time.

[00:01:45]The year is 874.

[00:01:47]Norse settlers sail in, led by a man named Ingólfr Arnarson. He finds the land empty, nobody to fight even, basically free for the taking.

[00:01:57]So, what's the first thing you do when you land on a freezing island with a winter coming that will most definitely kill you?

[00:02:04]You make fire.

[00:02:06]So, these guys burn charcoal to melt bog iron into knives and nails. They burn wood just to live through the dark. They cut timber for the longhouse, then more for the next boat. So, they cut and cut and cut and they keep cutting. Within 200 years, more than 95% of the original forest is gone.

[00:02:27]And historians have pinned almost all of it on the first few generations of Vikings.

[00:02:32]But, that's not the only reason. The settlers brought sheep for wool, then kept them [clears throat] for meat. And the thing about sheep is they don't really care about the rules of the plant herbivore population cycle.

[00:02:45]They will eat a baby birch the second it pokes its head out of the ground. So, every time the forest tries to crawl back up, there's a mouth waiting at ankle height to bite it off. The birch never gets a second shot at growing up.

[00:02:59]And so, by the year 1900, forest [snorts] covers under 1% of the whole country.

[00:03:05]But, the trees were doing a second job nobody could see.

[00:03:09]See, Iceland's dirt is weird. And I mean genuinely weird. It's made out of volcanic ash, so it's light and soft, almost like flour.

[00:03:20]Plants adore the stuff. The problem is it refuses to stay put.

[00:03:25]For thousands of years, birch roots actually sold that for free. Imagine every root as a thread and all of them woven together into a net stretched tight over the hillside. Pinning the loose dirt to the hard rock underneath.

[00:03:40]If you cut the trees, then you cut the net.

[00:03:43]Now, there's nothing holding the soil to the mountain but its own weight.

[00:03:48]And volcanic ash barely weighs anything.

[00:03:51]So, watch one bare hillside with me.

[00:03:54]A storm rolls in off the Atlantic, and the top layer of soil peels off and flies out to the sea.

[00:04:00]Next door, a little more. The storm after that, a little more. Slowly, the mountain gets stripped down to the bone.

[00:04:08]And then, the year 1104 happens.

[00:04:10]The previously sleeping volcano Hekla wakes up.

[00:04:14]It fired 2 and 1/2 cubic kilometers of ash and rock into the sky, and dropped it across more than 55,000 square kilometers.

[00:04:24]That's about half of Iceland buried under grit.

[00:04:28]For days, the sky rained gray.

[00:04:31]But, this was actually a silver lining.

[00:04:35]See, on bare gray ground, the ash lands on nothing. [clears throat] So, the wind grabs it and hurls it sideways for years on end.

[00:04:44]It becomes a sandblaster, scouring off whatever scrap of green managed to hang on.

[00:04:50]But, on a hillside that still has its trees and moss, falling ash is a gift.

[00:04:56]The plants catch it, hold it down, and over a few years, it rots into rich new soil. You want to see what that does to a place? Drive out to a valley called Hjoarsardalur.

[00:05:07]Before Hekla, it was packed with farms, good soil, big families, animals out in the fields. After the eruption, it was buried and abandoned, and it never came back.

[00:05:19]Icelanders call it their Pompeii. Dig into the ground there today, and the old farmhouses are still sitting under the ash, exactly where their owners walked away from them.

[00:05:31]So, basically, the wind strips one patch down to rock.

[00:05:35]That patch grows nothing now, so nothing holds the dirt together. So, the next storm peels that off, too.

[00:05:42]The bare spot spreads outward like a stain, eating a little more of the green every year. Cycle this process over a thousand years and Iceland lost about half the vegetation it started with.

[00:05:56]Half the soil underneath it washed into the ocean one grain at a time.

[00:06:01]Today more than 30% of the country is flat out desert and about half the island's soil are badly eroded. You'd think that means no rain, but that's wrong. It rains plenty here. It just hits the bare rock and gravel and runs straight off to the sea before the ground can drink a single drop. And the wind doesn't always work slow. On a bad day it can bury a whole farm.

[00:06:27]Take 1882.

[00:06:29]Gunnar Schoultz, a farm 95 km east of Reykjavik, sitting right at the foot of Hekla. One morning the wind picks up and then it doesn't stop for nearly two weeks.

[00:06:41]When it finally dies down, the farm is buried. Hundreds of sheep are dead.

[00:06:47]Their wool so heavy with sand they couldn't even drag themselves to shelter. A whole lake is gone, packed solid with blown dirt. And when the farmers walk out across what used to be open water, they find dead trout lying on top of the sand.

[00:07:04]So let's say hearing all this makes you want to stand with the trees. Who cares if the forest got cut down? So you'll grow a new one.

[00:07:12]You grab a sack of birch seeds, hike out to a bare hillside, kneel down and push your hand into the ground.

[00:07:20]And there's nothing to push into.

[00:07:23]No soil, just rock, gravel and a thousand years of wind. The dirt that grew the old forest sailed off to the ocean centuries ago.

[00:07:33]So you can't plant the tree because the tree needs soil and the soil needs the tree's roots to hold it down and feed it. Each one needs the other to come first, and neither one is there. That's the trap Iceland sat in for a thousand years, and breaking it took more than a bag of seed. It took a national law, a wall of fences, and one stubborn forester who got on a boat and sailed all the way to Alaska to find the answer.

[00:08:04]In 1907, Iceland's parliament decides enough is enough and passes the Forestry and Soil Act. That single law kicks off two things.

[00:08:15]A soil conservation service, which might generally be the oldest one on the planet, and the Icelandic Forest Service that grows out of the same effort.

[00:08:25]And they set up headquarters at Gunnarsholt, the exact same farm that Sandbird alive in 1882.

[00:08:33]The place that lost everything becomes the base camp for getting it all back.

[00:08:38]Kind of poetic. Still, one is simple: build fences. Look, the sheep are the entire reason nothing grows up. So, you take the last few surviving patches of birch, and you wrap a fence around them to lock the sheep out. That was basically the entire plan. The first fence goes up in 1905 around the birch wood called Hallormsstaður in the east.

[00:09:00]And behind that fence with zero sheep mouths in range, something incredible happens. The birch quietly starts spreading again on its own for the first time in centuries.

[00:09:12]But a fence can only save what's still alive. It does nothing for the bare hillsides where the soil is already gone. For those, you have to build dirt out of thin air.

[00:09:23]And in the 1940s, nobody on Earth knew how. So, in 1945, the head of the Forest Service, a man named Hákon Bjarnason, crosses the ocean to Alaska.

[00:09:36]Why Alaska? Because Alaska is basically Iceland's long-lost twin. Same line on the globe, same brutal cold, same howling wind, same fresh volcanic ground under your boots. If a plant can tough it out in Alaska, it's got a real shot in Iceland. He comes back loaded with seeds, like seedlings of Sitka spruce, lodgepole pine, and black cottonwood.

[00:09:59]Trees built for exactly this kind of environment. And one more thing, [clears throat] nobody saw coming. A purple flower called Nootka lupine. That little flower is the secret weapon. It's basically a soil factory. It pulls nitrogen straight out of the air and pumps it into the dirt around its roots.

[00:10:19]Drop it on dead gravel where nothing else will even bother trying. Give it a few years and you've got living soil where there was none.

[00:10:27]And just like that, the loop finally cracks open. Today, Iceland plants around 3 to 4 million baby trees a year.

[00:10:36]Every year since 1990, country's forest has grown more than six times over, from about 7,000 hectares to over 45,000.

[00:10:46]And that scrappy little birch wood at Hallormsstaður, it grew into Iceland's first national forest and one of the biggest in the country today. 40 km of trails wind through it.

[00:10:59]It's even got the only village in Iceland that sits inside a real forest.

[00:11:03]Then, they do something that sounds completely insane. In 2005, they launch a project called Hekluskógar, and they plant a brand new forest around the volcano Hekla, on purpose. Now, why would anyone plant trees next to a volcano that keeps blowing up? Because the trees are the defense. When Hekla erupts again, and it will, the ash lands on the forest instead of bare ground.

[00:11:30]The trees and the moss catch it and pin it down. So, instead of blowing across the whole island and kicking off death spiral all over again, the ash just settles in and rots into fresh soil.

[00:11:43]They're growing a forest to use as a shield against the next eruption. The very thing that destroyed the land is now going to feed it. I know, it sounds poetic. Again, want to prove the whole thing works? Drive to a tiny place called Kirkjubæjarklaustur.

[00:11:59]There's a Sitka spruce standing there, planted way back in 1949. In 2022, somebody finally put a tape measure on it. 30 m and 15 cm. The first tree to break 30 m in Iceland since the Ice Age.

[00:12:14]The Prime Minister herself showed up to help measure it. And the climate payoff is real, too. In 2022 alone, Iceland's young forests pulled about 505,000 tons of carbon dioxide out of the air. That's 17 times more than those same forests grabbed in 1990. So, everything's perfect now, right? Yeah, about that.

[00:12:36]The lupine turned on them. The purple flower that saved the soil got a little too good at its job and spread everywhere. Drive Iceland's Ring Road in June and for miles it looks like someone paved highway straight through a sea of purple. Beautiful, but it's now smothering the native heather and wild berries that were supposed to come back.

[00:12:57]So, Iceland slapped it with an official label, invasive species. The cure grew into a brand new disease. So, after more than 100 years of fences, flowers, and trees shipped from Alaska, there's only one question left. Is Iceland actually pulling this off? Slowly, yeah, it is.

[00:13:17]Forest cover is back up to around 2% and climbing. That sounds like nothing until you remember it's the first time that these trees have gained ground in a thousand years. But, forget the trees for a second. The number I love most is the sheep. In 1977, Iceland had 896,411 of them. Way more sheep than people.

[00:13:41]Today, it's around 365,000.

[00:13:45]Fewer sheep than there are people. The flocks that ate every seedling for a thousand years are finally thinning out and the land gets room to breathe. The country wants forest cover at 12% by the year 2100.

[00:13:59]So, nobody working on this gets to see it finished. The foresters who planted the first trees are already gone. The kids planting saplings this spring will be gone, too. They're all growing a forest that they'll never get to stand in. But, a thousand years from now, somebody's going to walk through real woods here and never know if they're standing on what used to be bare rock.

[00:14:21]If you made it this far, do me a favor and smash that like button. See you in the next one.