American lumber capitalist who put together a syndicate owning millions of acres of timberland, as well as sawmills, paper mills, and other processing plants.

An immigrant who left Germany when he was 18, Weyerhaeuser started in the lumber business as a sawmill worker in Rock Island, Ill. After the business failed in the panic of 1857, he decided to buy it. In 1860 he took as a partner Frederick C.A. Denkmann, his brother-in-law. While his partner ran their mill, Weyerhaeuser travelled through Wisconsin and Minnesota buying stands of timber. He also began acquiring an interest, often a controlling interest, in many logging and milling operations. In 1872 he organized the Mississippi River Boom and Logging Co., a huge confederation that handled all the logs milled on the Mississippi.

In 1891, Weyerhaeuser moved to St. Paul, Minnesota, where he and his next-door neighbour, railroad tycoon James J. Hill, made one of the biggest land deals in U.S. history. In 1900 he bought from Hill 900,000 acres of timberland in the Pacific Northwest for $6 an acre, thus founding the Weyerhaeuser Timber Company, centred in Tacoma, Wash.

During his lifetime, the company purchased almost 2,000,000 acres of land in the northwest at an average cost of $8.80 an acre. In addition, the Weyerhaeuser syndicate managed his many interests and partnerships in both timberland and sawmills in other parts of the country. Weyerhaeuser never changed the names of firms that he controlled, but he was president of 16 lumber companies and a large shareholder in many others. One of the 30 mills in which he had an interest was the Potlatch, Idaho, mill, which would later become Potlatch Corporation. He also owned part of what is now Boise Cascade Corporation.

The Weyerhaeuser Company (as the company was renamed in 1959) is still a world leader in lumber sales.