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Capillary action is not nearly strong enough to permit tall trees. This is a common misconception. The stronger mechanism is negative pressure, caused by transpiration at the top of the tree, pulling up miniscule strands of water under high tension.

Note, however, that the surface is also at a slightly larger radius from the center of that increased mass, so the net increase in surface acceleration is less than 1.2%.

[Edit: Note that the moon is less dense than the earth. By my calculations, adding the moon's material to the earth (and keeping it at the moon's density) would increase the earth's radius by 43 km, and (if you accept the parent's 1.2% mass increase figure), the surface acceleration would be 0.998 times the current value.]

The added mass would also increase the size of the Earth, which would reduce the surface gravity. Overall the end result would be something like 0.4% higher surface gravity.

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