It is totally en vogue for environmental groups and municipal communities to pick an arbour day (or any other event) to head out and plant groves or scattered plantings of trees. After all, trees help to mitigate carbon dioxide in the atmosphere, provide shelter, hold winter snow and provide habitat (don’t they?). Any planting must be better than no action at all.Another example of well-meaning but uninformed endeavour, there is more to it than …