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51 votes

How did forests end up covering pyramids?

I am an archaeologist and I specialize in the ancient Maya. Here's how it happens: 1: The vast majority of ancient Maya buildings are built using a "core and veneer" technique. The bulk of the ...
LAT's user avatar
  • 631
37 votes

Why do trees break at the same wind speed?

Why do trees break at the same wind speed? Image source: Wikimedia Commons Note that in the above image, that almost all of the trees had their tops snapped off. This claim is about tree's being ...
David Hammen's user avatar
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15 votes
Accepted

How did forests end up covering pyramids?

The accumulation of soil in such situations takes a long time. The main way soil would have been naturally transported there would be by the wind. The wind blown soil would get caught and accumulate. ...
Fred's user avatar
  • 24.7k
9 votes

Why do trees break at the same wind speed?

As the other answer points out, this is very likely an evolutionary adaptation that balances sturdiness with unnecessary overengineering. From a physics perspective, the relatively constant breaking ...
Nuclear Hoagie's user avatar
8 votes
Accepted

Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?

I cannot find any language in peer-reviewed literature (as far as publicly accessible) that makes the 20% claim reported in the question. I therefore consider this claim to be of obscure and dubious ...
njuffa's user avatar
  • 558
8 votes
Accepted

How do optical satellites detect different leaf types?

Short answer Different plants reflect light at different wavelengths with specific patterns. If you know the reflection pattern of a broad-leaved forest and that of a needle-leaved forest, you can ...
Andrea Massetti's user avatar
8 votes

Why do trees break at the same wind speed?

The general claim seems to be incorrect: This phenomenon is independent of type and size of the tree. Based on other answers, the claims around this appear to be that the scale of the tree doesn't ...
JimmyJames's user avatar
6 votes
Accepted

With humans out of the equation, what could cause forest fire?

Wildfires are mainly caused by humans (or their technology) and lightning. Lightning is the most prolific natural source. There really aren't many other sources in most areas, unless there is ...
f.thorpe's user avatar
  • 13.8k
6 votes

Historical data on world's forest area

When I need data about past and future projected land use change, I usually refer to the global dataset that was developed for the global climate simulations CMIP6. The dataset is the Land Use ...
Nemesi's user avatar
  • 1,268
5 votes

Do trees capture more CO2 during a fast growth stage?

Right, there are a lot of misconceptions about this. They are mostly to do with the difference between the magnitude of carbon storage and the rate of carbon uptake, and also the difference between ...
Will's user avatar
  • 494
5 votes

Trees: What does "highly tapering stem" mean?

A "highly tapering stem" is simply that the trunk of the tree is less cylindrical and more conical in profile. It's a problem because while you may have a lot of timber volume you don't have as much ...
Will's user avatar
  • 494
5 votes

How do optical satellites detect different leaf types?

In general, no, NDVI is not used to derive vegetation type. NDVI is useful for studying phenology, but it won't tell you the type of plant that is being remotely sensed. Good land cover systems use ...
f.thorpe's user avatar
  • 13.8k
5 votes

Why is ground water rising on these forest rings?

Nobody knows - yet. But one can say that these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors, as some ...
Gordon Stanger's user avatar
5 votes

Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?

Do we need to worry about oxygen? No. Although some reports have claimed the Amazon produces 20% of the world’s oxygen, it is not clear where this figure originated. The true figure is likely to be ...
Keith McClary's user avatar
5 votes

Why do trees break at the same wind speed?

Some excellent answers are already available, but they are all examining a single tree in isolation, as if putting a tree to a wind tunnel to see whether it snaps or not. That's not how every trees ...
Jirka Hanika's user avatar
5 votes

Looking for study on the pollution of the forest

So far, I thought there won't be any studies on the overall scenario of waste disposals. After searching in depth, I have found studies on illegal waste dumping sites in Polish forests. Hope these ...
Padmanabha's user avatar
4 votes
Accepted

Is the Amazon rainforest resistant to fires?

Most fires are probably in the periphery because they are started by humans. They encroach on the jungle from the outside, where they already live, and there are roads instead of impenetrable jungle....
Jan Doggen's user avatar
  • 2,679
4 votes

How did forests end up covering pyramids?

Most of the Mexican pyramids are less steep than their Egyptian counterparts, and have niches and terraces which their Egyptian counterparts don't. An important difference is the climate, which is ...
Michael Walsby's user avatar
3 votes

Why do trees break at the same wind speed?

One important additional factor is that the stress (and damage) isn't linear. A very basic idea is that energy is velocity squared. But Prahl et. al. 2008 included some review of the theories on ...
JeopardyTempest's user avatar
3 votes

Origin of Serious Wildfires

There was an interesting paper on this for the United States a couple of years ago: Balch et al (2017) Human-started wildfires expand the fire niche across the United States, PNAS, doi: 10.1073/pnas....
Deditos's user avatar
  • 3,960
3 votes

Can reforestation sequester our annual carbon emissions?

Reforestation is a one-off gain in carbon storage. Once a forest is fully mature, the carbon cycles back into the atmosphere as trees die and decay or are burned. So no, this will not sequester all ...
haresfur's user avatar
  • 4,419
3 votes

Does anyone know a book/article/research that talks about forest fire prevention?

This book is based on Australian experience, some of it may be relevant of North American wildfires. I read it ten years ago. Paul Collins, Burn - The Epic Story of Bushfire in Australia, Allen & ...
Fred's user avatar
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3 votes
Accepted

Why don't forest fires in Western Australia get as much attention as forest fires in the southeast of the country (including SA)?

Forest fires, and natural disasters in general, get attention when they affect people. Bush fires outside of metropolitan Perth or far away from populated areas do not affect many people. Therefore, ...
Gimelist's user avatar
  • 23.2k
3 votes

What would be the effects of a large forest fire on soil in other places?

Falling ash is usually not a concern for agriculture. But the particulate matter (smoke) can harm agricultural products. Not through the soil, but by exposing the plants to smoke over long periods. ...
f.thorpe's user avatar
  • 13.8k
3 votes

What would be the effects of a large forest fire on soil in other places?

After Saint Helens, forest managers thought to harvest timber in the area and replant it because they assumed nothing would ever grow again. Instead they left it alone and the eruption epicenter is ...
LazyReader's user avatar
3 votes

What would it cost to stop Canada forest fires?

What makes you thing money can solve such a problem? Canada, like most other countries that are prone to wildfires does not have enough fire fighting personnel to attend to all such fires. Presently, ...
Fred's user avatar
  • 24.7k
2 votes

What are these clearings in Amazon rainforest?

Hard to say. Some could be clearings for log landings, some for small villages or outposts used by the military or others, some cleared due to natural disturbance in the area (e.g. fire from ...
cr0's user avatar
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