While in Truro, NS, I saw a flatbed trailer parked at the community centre, surrounded by multiple police cars. A tall coniferous tree lay on it, like a tethered giant. A huge crowd (well, huge by small-town standards) was gathered around the tree, with people tying cards and letters to its branches. This was Boston's Christmas Tree, pausing on its trip to the US.
In 1917, a few weeks before Christmas, a munitions ship detonated in Halifax Harbour. It was the world's largest explosion before the development of nuclear weapons. Thousands died, thousands more were injured. Nearly every building had its windows blown out. Then a blizzard dumped 41 centimetres of snow on the wreckage, and the survivors began to freeze.
The city of Boston sent a relief train loaded with blankets, medical supplies, and $750,000.
So every year, Nova Scotia sends the city of Boston the biggest and best Christmas tree it can find.