I'm in Ottawa Canada and noticed dozens of trees presumably maintained by the municipality with bark mulch heaped about 8 inches high, tight up against the tree trunk. I could not tell whether this was done earlier this season or last. From what I've read on this site and elsewhere these trees are doomed to die or suffer poor health. If this is the case, how long does it take for the trees to be negatively effected by this practice? I saw some others which had mulch similarly placed, surrounded by rubber/plastic border material. I'll see if I can borrow a camera to post some pics.