So I planted 1,000 trees over an eight-year period, and then Ronny Reagan said that trees cause pollution. Apparently, a University of Helsinki study confirmed this assertion in finding that trees, especially conifers, release volative organic compounds that pollute. In addition, they release NOX which contributes to smog.
I'm not getting into a pissing contest with those who disagree; hell, I ain't a scientist anyway. But there is no doubting the fact that trees use copious amts. of H2O which, we are remineded, is in short supply for an ever-growing world population.