Hot answers tagged

13

It will depend on the time of year and the time of day. As you noted, you often see more frost in an open field than in a forest. A comment indicated the forest insulated the surface but I believe it will also reduce radiant heat loss at night, compared to the open field. During the day, the ground surface is more shaded and the trees reduce the advective ...


11

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 water such as lakes and dams also contributes. Another significant contributor, on a local level, is transpiration from forests. the Amazon alone creates 50-...


10

Leaves, mostly. Photosynthesis requires carbon dioxide, and it gets it via stomata - small controllable pores in the leaf. When the stomata open, water goes out, because the air is generally drier than the interior of the leaf. Water in the leaves is drawn up from the roots, via the xylem, using the suction from the lost water in the leaves, and also acting ...


9

Don't forget the protection from wind in colder seasons as well. Basic survival skill is to always make shelters under cover (as in a forest) rather than in an open meadow. On a cold day it may not feel much warmer in still air but getting out of the wind does make a significant difference.


7

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 compare them with the pattern observed with a satellite and conclude to which forest it is more similar. Long answer Optical remote sensing Optical sensors ...


7

One of the consequences that I find more fascinating with the increased CO2 problem is the changes that affect specific components of the environment. One example that I like is the effect on poison ivy. Researchers at Duke University (Mohan et al., 2006), as part of their Free-Air CO2 Enrichment (FACE) experiment, reported a large change in poison ivy ...


6

If you increase CO2 concentration and keep all other parameters at there current level, then biomass production should go up. The reason is simply that CO2 is one of the building blocks biomass is made of in photosynthesis. In the real world it's trickier than that of course. Here you have to take into account how natural cycles will be affected by ...


6

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-position-15897370


5

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 a variety of data sources to derive general plant type (e.g. conifer vs deciduous). For instance, the National Land Class Database (NLCD) description states: ...


5

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 volcanic activity or a meteor strike as you mention. There are also occasional cases of wildfire when peat dries out. During a hot-dry summer, it can take several ...


5

This is counterproductive, both ecologically and economically, and is also well beyond the capabilities of current robots. Ecologically counterproductive Forests have evolved to live with, and in many cases, to depend on forest fires. Aggressive fire prevention by the US Forest Service and other agencies throughout much of the 20th century resulted in ...


5

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 carbon stored in it. Whereas although a carbon reservoir might exchange individual carbon-based molecules with other parts of the carbon cycle, as much will go out ...


4

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 and slopes is never uniform. Also the calculations to determine the true area can be convoluted if the change in topography is complex.


4

It seems that tropical forests absorb more carbon dioxide than many scientists have believed before. NASA and NCAR scientists have shown that tropical forests absorb 1.4 billion metric tons out of a total global absorption of 2.5 billion metric tons. This estimate is much larger than previous estimates and the tropical contribution seems to be much larger ...


4

CO2 can only enhance plant growth when other resources such as nutrients or water are not limiting growth. If N for instance is scarce, no matter how much you increase CO2, plants will not take advantage of the increased CO2 concentration.


4

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 have suggested. For what it is worth, here is my own hypothesis: The areas concerned are all periglacial in an area of abundant boulder clay. In colder ...


4

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 and then mixed with water. These days, items that were once made from natural clay, such as terracotta pots and tiles for roofs, are now made from crushed shale....


3

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 & Unwin, 2006, ISBN 9781741750539, ISBN 1 74175 053 9. Part 4, titled: The Great Fire Debates, has three chapters (9 to 11); 09 To burn or not to burn 10 ...


3

It has been suggested that proper management of large herds of goats, cattle, deer, or elephants on the land are effective in preventing desertification. So perhaps this could be used to mitigate conditions leading to excessive grass and forest fires. Maybe your idea would scale-up more effectively if the robots were set to manage large herds of animals that ...


3

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 Malaysia. The number of species involved is a few dozen at most. As 'N9ZN' points out, trying to develop generalizations would be a titanic task, and essentially ...


3

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 from a coal mine, so it's probably crushed and milled. Assuming it is clay, there are some problems with that. As Fred said, clays expand and contract with ...


3

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 and even if a species is not common in this part of the UK it might be brought there e.g. as a secret passanger in a car.


3

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 the emissions from fossil-fuel burning. It could help offset it in the short term, but probably mainly just offsets the carbon dioxide from deforestation.


2

Just by looking at a treeless region it would be difficult to know whether it was naturally treeless or whether the lack of trees was due to human actions. The history of the region would need to be known. In Scotland, due to the extent of glaciation during the last ice age some of the ground was scoured, leaving bare rock when the ice finally melted. With ...


2

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 the rest of the system per unit of time, for example kilograms per day [kg C/day]. A coal or oil deposit can be either a reservoir or source, as carbon flows ...


2

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 lightening strikes) though I'd expect the latter to have sparse canopy and not be totally clear. Many of these patches don't have signs of good access routes (other ...


1

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, media attention is diverted elsewhere. This is not unique to WA: you have the same in NT, northern SA, and the west of eastern states. This is also not unique ...


1

From my correspondence with Dr. Hamilton, who is one of the leading researchers on forest rings (emphasis mine): They can be irregular (see figure below) but it is not very common. You are right, the circularity is why we notice them and there are probably lots that we don’t notice because they are not round. However, the mechanism of formation that ...


1

Between timberline and treeline lies "krumholtz", a German word meaning broken or bent wood". Great place to hike.


1

How much forested land is currently protected from logging/deforestation? I doubt that could be answered with anything better than a rough guesstimate. We would first need to know how much land is OFFICIALLY/LEGALLY protected. Then we would have to subtract acreage to allow for illegal logging or general environmental destruction. There are also areas ...


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