Production of steel and concrete produces significant amounts of the greenhouse gas carbon dioxide, while wood holds the carbon from CO 2 removed from the atmosphere through photosynthesis. So using wood in the structural elements can help offset the carbon emissions from the other parts of the construction process and from the operation of the finished building. A timber tower uses a lot of wood. This is not conventional frame construction, in which two by fours and other thin elements are nailed together, but more akin to building with concrete slabs. The tower in the Skidmore, Owings & Merrill study, for example, would contain about 3.9 million board-feet of wood; a typical single-family home contains less than 20,000 board-feet of framing lumber.

The use of so much wood raises the issue of the potential impact on forests if wooden buildings were to become prevalent. Mr. Baker noted that in the United States and Canada, about 60 billion board feet of lumber was harvested each year, and as long as forests were managed, sustainable wooden buildings should not have much of an impact. There are also millions of fir trees in North American forests killed by a widespread beetle infestation that could be used to produce the timber panels.

The Skidmore, Owings & Merrill system uses a type of engineered wood called glued laminated timber, or glulam, for the building columns, and cross-laminated timber slabs for the central core, floors and shear walls, which provide stiffness against wind loads. But the concept calls for concrete beams along the perimeter of each floor and elsewhere to allow for longer spans and thus more flexibility in floor layouts.

The case study 42-story building in the report is based on an actual Skidmore Owings & Merrill tower, the Dewitt-Chestnut apartments (now called the Plaza on Dewitt) in Chicago, that was built in 1966. That building, made of steel and concrete, had an innovative structural design — it is basically a tube that acts like a vertical cantilever to resist wind loads — that was used in later buildings, including the Sears Tower.

“It was a landmark structure of its time,” Mr. Baker said, and it used materials very efficiently. “We wanted to benchmark against a building that was very efficient,” he said.

Mr. Green, in his report, presents a system that could be used to build towers in seismically active areas like Vancouver. Rather than concrete, he uses some steel beams to allow the building to better respond to earthquake forces and handle wind loads.

His feasibility study looked at buildings up to 30 stories. “But we stopped at 30 stories only because at the time that was considered so beyond the comprehension of the public,” he said.