While the usefullness is debatable, I'm a little concerned about the tree friendliness.<p>From what I can see on the pictures, the standoffs, including the side stability lugs shown in one of the pictures might be too small to avoid risk of damage to the bark.<p>For most trees, short mounting time, and light load it is probably fine as the page states, but someone walking into the table, or trying to sit on it, would likely damage at least some species of tree.<p>Use on your own trees as you wish, but maybe avoid things like this on community/park trees, at least not without additional padding and some understanding of how robust the particular kind of tree is.<p>Trees are very strong, but the bark isn't always.<p>Padding for trees should almost always be smooth on the tree side to avoid abrasion when mounting, no harder than the tree outer and inner bark, and spread the load ... sufficiently.<p>What is sufficient will vary from species to species, and to some extent by age, but considering some trees have a soft enough bark that you can at least superficially damage it with a fingernail, there are no obvious rules.<p>Err on the side of caution.