Loggers in the Clayoquot Sound region of British Columbia chopped down a few old-growth trees yesterday to the sound of cheers from Canadian environmentalists. After a bitter, 17-year battle over logging in the region’s forests, enviros are backing a new company called Iisaak Forest Resources, which will practice small-scale, selective, sustainable logging, removing the downed trees via helicopter and promising to leave healthy ecosystems behind. The company, controlled 51 percent by five native tribes and 49 percent by Weyerhaeuser, has the formal support of Greenpeace, the Sierra Club of British Columbia, the Western Canada Wilderness Committee, and other green groups, which say they will help market the sustainably harvested timber.