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 ...
- 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 ...
- 22.6k
16
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. ...
- 23.2k
11
votes
Accepted
Do forests affect local rainfall and climate significantly?
For rain to fall, water vapour must exist in sufficient quantities in the atmosphere. The main source of atmospheric water vapour is evaporation from oceans. However, evaporation from large bodies of ...
- 23.2k
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 ...
- 380
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 ...
- 473
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 ...
- 198
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 ...
- 196
7
votes
What is the difference between a carbon sink and a carbon reservoir?
The difference is that a carbon sink accumulates carbon, whereas a carbon reservoir has accumulated carbon.
That is to say:
A carbon sink is an ongoing process which is increasing the amount of ...
- 4,090
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 ...
- 12.9k
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 ...
- 1,258
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 ...
- 12.9k
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 ...
- 14.1k
5
votes
Accepted
What is the name for the forested areas in mountains below the treeline?
Forests directly below the alpine tree line are high-elevation or Montane forests. See more about Montane ecology here.
Image from http://www.nature.com/scitable/knowledge/library/global-treeline-...
- 12.9k
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 ...
- 2,349
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 ...
- 494
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 ...
- 494
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 ...
- 191
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 ...
- 347
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 ...
- 4,537
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....
- 2,657
4
votes
Accepted
Mud bricks with shale
Your idea has merit. Shale is classified by geologists as being a mudstone. It is composed of silt and clay sized minerals.
According to this geology website, shales can be crushed to produce a clay ...
- 23.2k
4
votes
Accepted
Wildfire acreage, two dimenional or three?
The same issue arises when land is bought and sold. The area used is the flat area from a plan. Slope is not considered because it would require at lot of data because the rate of change of topography ...
- 23.2k
4
votes
What is the difference between a carbon sink and a carbon reservoir?
A carbon reservoir is measured by the amount of carbon it contains, for example kilograms of carbon [kg C]. A carbon source or sink is measured by the amount that comes out or into the reservoir from ...
- 3,790
3
votes
Crickets found in Wales?
There are crickets species living in Wales (Reference)
Field Grasshopper
Green Grasshopper
Meadow Grasshopper
Roesel's Bush-cricket
Oak Bush-cricket
Speckled Bush-cricket
Mottled Grasshopper
...
- 159
3
votes
How do I estimate the mass of a deciduous tree's leaves?
David LeBauer is correct in saying that there are 'allometric equations' to estimate the leaf biomass, but they only refer to small experimental plots in such places as Hawaii, Japan, Singapore and ...
- 14.1k
3
votes
Mud bricks with shale
Adding to Fred's answer, there are two points you have to take into consideration:
Whether the "shale" is actually composed of clay minerals, or is it something else. You said it's what they took out ...
- 22.9k
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....
- 3,906
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 ...
- 4,419
Only top scored, non community-wiki answers of a minimum length are eligible