Trees on Mars?
The pressure is more supportive than NASA advertises, but caution is needed in photo analysis.
This web site has already presented compelling evidence/proof that air pressure on Mars is much higher than the classically accepted 6.1 mbar at areoid. See Mars Pressure Abstract and links at http://davidaroffman.com/catalog_1.html. However, based on a number of photos from Mars Global Surveyor and Mars Reconnaissance Orbiter, some people think there's evidence for trees there too. Fo now I'll just discuss one photo: MGS photo E0700860 shown below. Please look at the objects assigned red numbers and letters. The number corresponds to a suspect tree (1, 2, 3 and 4). The letter S after each number corresponds to what might be a shadow. Objects 1 and 2 look like almost the same size, but the "shadow" for 1 looks a good bit longer than for 2. Object 3 is a lot smaller than object 1, but its "shadow" is about the same size. Object 4 is bigger than 3, but its shadow is comparable or smaller. What does this mean? I think the shadow lengths should be in the same ratio as the object sizes if they are shadows. However, what we may be seeing here are dust remains that generally point in the same direction due to the prevailing winds. Also, each "tree" rather resembles a flame, with a bright area up top and to the right. These bright areas might also be due to to dust. How can both be true, that the dust appears light and dark? If the wind scoops the dust out of a depression, it would catch the sun's rays more when lifted (thus appearing light) and then the dust would appear dark when it reaches the ground again. This is where color becomes important. We lose a lot in black and white.
DISCUSSION OF FIGURE 1: Dr. Tom Brennan wrote, "the shadow belonging to what you've labeled object 3, actually contains a smaller object which is extending the shadow. Another factor that can affect the length of the shadow is local topography, or small hills, which can make a shadow longer or shorter depending. Over all, I'd say the shadows seem proportional to the height of the objects."