VANCOUVER, June 7 (Reuters) - United States forestry giant Weyerhaeuser Co. (NYSE:WY - news) increased its stake in western Canada on Wednesday, purchasing British Columbia lumber producer Coast Mountain Hardwoods.

Delta, British Columbia-based Coastal Mountain markets primarily to furniture makers, and has already purchased about 40 percent of its lumber from Weyerhaeuser, officials at the two companies said.

Financial terms of the deal with Coast Mountain's former owner, the Boston-based venture capital firm Advent International Corp. were not disclosed.

The purchase includes a 42-million board feet capacity lumber mill, drying kilns with an annual capacity of 20 million board feet, a 25 million board feet annual capacity abrasive planer and five volume-based forest licenses.

Weyerhaeuser, which has its headquarters in Federal Way, Washington, is already British Columbia's largest timber producer, a position it secured last year with the purchase of Canadian rival MacMillan Bloedel. Error: Unable to read footer file.