So the Amazon is all secondary growth forest then, is it?

Researchers have revealed the massive scale of “lost cities” in the Amazon rainforest and uncovered new details about the lives of the people who lived there.

The existence of centuries-old settlements constructed by the Casarabe tribe who lived in what is now Bolivia was already well known.

But the extent of the sites had not previously been realised, and details of how the tribe lived was shrouded in mystery.

The veil has been lifted thanks to an aerial survey using technology known as Lidar, which uses a pulse from a laser to collect measurements as well as creating maps and 3-D models.

That is interesting, no? For it means that “preserving” it isn’t a necessity. We can use it then, as we decide not to, it will grow back again.

27 thoughts on “So the Amazon is all secondary growth forest then, is it?”

  1. Just like the forests of New England.

    Or even (to take a local example) the woods of the Blackdown Hills, where you can find the remains of the occasional farmhouse deep under the trees.

    In fact, you can find examples of the phenomenon wherever you look on the planet, assuming you actually want to find it.

  2. The Amazon rainforest is unlikely to be natural. It’s the diversity of plants & that so many of the plants are useful suggests why it isn’t. In a natural forest, the plants most suited to the environment will predominate & crowd out ones that aren’t. The Amazon’s more likely to have been gardened by the people who built those cities. They planted what they preferred. And when they departed, it ran wild.
    Wait a couple of millennia to let the crowding out process continue & the Amazon would look different from what it does today

  3. There’s part of Queens Wood in Highgate you can see this in process. There was a house there. Odd bits of the foundations are still visible. Some of the orchard remains, although lack of care hasn’t done much good to the apple or plum crop. There’s plants you wouldn’t expect in English woodland. Still some roses & other garden plants. But it’s all in the process of being crowded out by the normal woodland deciduous. Oaks etc. Earlier in the process it was blackberry brambles ran riot. But they die back as the trees deny them light. Another century & you will have lost the apples & plums & probably the blackberries. Be like the rest of Queens Wood. Climax deciduous forest but not much growing underneath it.

  4. Theophrastus (2066)

    It is unlikely that all the 2.1 million square miles of the Amazonian rain forest are regrowth following human clearance. That said, rain forests regenerate remarkably quickly. Parts of Rio have returned to rain forest – with most of the original flora and fauna, including butterflies the size of birds.

  5. Theo. In 1492 Europe was the result of human clearance. Population around 60 million. S. America had a population of 30 million & Amazonia was the most fertile area.
    Agriculture in Europe was based around grain production. Cleared & ploughed land. The Americas didn’t have wheat. Staples were maize & yuca plus crop bearing trees. A lot of the agriculture in the Amazon area wouldn’t have looked much different at first glance to it does today. It’s a matter of what was grown & accessibility.

  6. Theophrastus (2066)

    Colour me sceptical, BiS. Even if the 30m population of South America in 1492 were all living in Amazonia, that would give an average population density of just c.4 people per sq km, so there was plenty of room for vast areas of virgin forest. Amazonia is not all pristine wilderness, but a lot of it is and meets the criteria for virgin forest– eg never logged, multi-layered canopies, coarse debris, standing dead trees, and so on.

  7. Yes, but:

    ” virgin forest– eg never logged, multi-layered canopies, coarse debris, standing dead trees, and so on.”

    After 500 years that would be true of secondary forest that regrew after the cvilisation collapse, wouldn’t it?

  8. Things like the North Yorkshire Moors are not pristine wilderness. It’s managed moorland. Left to its own it would become colonised by small shrubs, which would provide shelter for large shrubs, then small trees, then large trees, then woodland, then forest. Which it used to be before humans started clearing the land, and which you can see happening in highway verges where shrubberies aren’t cleared away.

  9. Theo. You’re thinking European agriculture. Clear the forest & plough. S. Americans didn’t have wheat. Where they wanted to clear the land, slash & burn, plant what you want to grow. Discourage what you don’t. There’s whole areas of terra preta, soil mixed with charcoal. As I said earlier, they gardened not farmed. It’s still a forest but it grows what they wanted it to grow. Over thousands of years they changed it.

  10. “the criteria for virgin forest”: I can remember a fuss in Australia about a plan for logging in virgin forest Then someone found photos of that land after the previous logging some (?) 70 years before. Ha, ha, bloody, ha.

    @Theo: “She is technically a virgin, m’Lud, because I have here a definition consciously crafted to evade the point”.

  11. Theophrastus (2066)

    TW: “After 500 years that would be true of secondary forest that regrew after the cvilisation collapse, wouldn’t it?”
    Up to a point, but you could still tell the difference with a detailed analysis.

    BiS: of course, the early residents of Amazonia slashed and burned, but probably on a cyclical basis in certain areas around their settlements. The idea that such a thinly distributed population could have gradually slashed and burned the whole of Amazonia is just not plausible.

    Dearieme: that some people have made refutable claims about particular forests being virgin doesn’t imply that it is impossible to distinguish objectively between ancient (virgin) forest and regenerated forest. The fingers of regenerated rain forest near the centre of Rio are subtly and not so subtly different to (say) the rain forests in Parana State beyond the Iguazu Falls.

  12. Tropical forest is a parasite mosh pit. So if, as BiS says, they gardened instead of farmed, it would have made sense to them to plant widely spread with a great variety of trees / shrubs / edible roots or whatever, to limit plant contagions.
    It would have meant a lot of walking, however.

  13. It’s been known for ages that the Amazon forest is mostly new. New in geological time anyway. Only about 10% is ancient, by memory more than 50,000 years.

    But the greens don’t read real science.

  14. I live in area that was logged out 75 years ago, on Google maps you can’t see my house because of the amount of trees and foliage.
    Admittedly they aren’t as big as the stump in my back garden which is about 15 to 20 foot diameter and the nearby 500 year old cedar that was left is truly impressive, but if you didn’t know better you’d think it was much older than 75 years

  15. Why can’t we decide to stop logging now? Are the ecosystem services benefits of not logging marketable assets?

    And didn’t old loggers leave lots of trees, so previously logged forests still contain significant real old growth?

  16. Why can’t we decide to stop logging now?

    The Greens want us to build in wood. Can’t have both.

    Also the Amazon is not felled for lumber, which it has almost none of. It is felled for farm land.

  17. ” The idea that such a thinly distributed population could have gradually slashed and burned the whole of Amazonia is just not plausible. ”
    But constant discoveries like the one in the article indicate that the Amazon wasn’t thinly populated. You don’t build cities with a population density of 4/km². You need a large productivity surplus to build it in the first place & a productive hinterland around it to support it. More & more it’s looking like earlier population estimates for the times were wildly inaccurate.

  18. Theophrastus (2066)


    You mentioned the figure of 30m as the population of South America in 1492, not me. Not all of those people would have lived in Amazonia: many would have occupied the littorals, for example, where there’s evidence of potato cultivation from c.3000bc.

    “You don’t build cities with a population density of 4/km².” Of course you can and people did, because that’s an average figure.

    A city in the ancient world with a population of 6000 needed (roughly) a labour force of c.2500 to manage and cultivate an area of c.1200ha or 12km² annually (with another c.1200ha left fallow). So even if (which is unlikely) there were 10,000 cities of 6000 people in Amazonia in 1500, then this hypothetical total population of 60m was cultivating (including fallow land) 240,000km² out of a total of 6.7 million km², leaving most of Amazonia pristine.

  19. the indigenous people of Australia and British Columbia both publicly blamed recent wildfires in part on not being allowed to practice traditional land management. Telling a green they are acting a bit ‘colonialist’ in their desire to stop these ancient tradition practices and should be respectful of such ancient knowledge and it’s quite amusing to see the conflict on their face.

  20. Questions of population and density are largely immaterial until we have an idea how old these cities are. Did any exist concurrently are we seeing cities and civilisations popping up in one place, “something happns” and the city is abandoned and after a few dozen or hundred yearsup pops another oner. Don’t we see this in Central America wherd civilsations rise and fall cyclically ?The Aztecs and their associates were just the latest iteration when the Spanish arrived. Did the Portuguese accidentally wipe out civilisations that they never actually encountered?

    “Hey it’s Og from the coast ! Wassup Og ?”
    “A load of guys with facial hair and white faces wearing metal hats have landed on the far east end of the coast. Call themselves Porty Geezers. Urggh!” ( Drops dead of smallpox)
    “Ooh, i thought he looked ill, wonder what those funny spots are…”
    Etc etc

  21. I’d say Otto suggests what probably happened. History of the Amazon area goes back just as far as The Fertile Crescent in the Middle East. Thousands of years. It wasn’t just whatever millions over one period. Unfortunately so little is known about it.
    And he’s also right about how disease spread through the indigenous population. And it spread much faster than Europeans explored.

  22. “Did the Portuguese accidentally wipe out civilisations that they never actually encountered?”

    The guesses at the source of infection that wiped out so many Indians in New England before the colonists arrived are (i) overland spread from the Spanish far further south, or (ii) infection from the European cod fishermen on the coast. Anyway, the colonists encountered already cleared fields and defunct villages. They viewed this as God’s will presumably.

  23. Did the BC first people even cut down trees? Did their burns even harm the tough old growth? Why can’t we 3D-print houses out of mud and substitute bamboo for wood to make furniture, fences, etc.?

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