Because 10% of the population have nothing to do in a day and voluntarily plant trees? Hmmm...
I might be underestimating Ethiopians though...
Did you try reading any of the links people have added in this thread? Schools and government offices were closed. This was a big event that was planned for months. 10% participation sounds absolutely plausible if not lower than I'd expect.
No. I would assume if this was such a big event that the original article would cover it.
I guess it was that big that they did not need to add any details.