My first post ever on bay12forums and I'm posting about trees.
Darn, I knew that trading and being friendly with those elves would affect me somehow, I just never imagined this...
Anyway, one thing that I have been thinking about is how there seems to be no mechanic for old trees dying and falling over of their own accord in fortress or adventure mode. I think that some sort of mechanic that caused old trees to fall over after a period of time would make the game slightly more interesting, as it would add to the look of the landscape. The rate or age at which trees fall could be slightly random, and based on the dampness of the biome and wind-speeds. After the trees have fallen, including trees felled by a woodcutter, the logs would start to rot over time and gradually go from wood to rotten wood to mulch to humus, with the rate of rot based on what type of wood it is.
Another optional feature that could be added would be the possibility for trees to damage buildings or constructions if they fall on top of them, or injure dwarves in the way. I'm not sure of all of the features necessary for this sort of thing are currently in the game, but if they are or are added later, it could add tangible benefit to having a skilled wood cutter. Wood cutters would automatically attempt to fell a tree away from the nearest construction or building and would have a chance to fell it in a different direction based on their skill level.