Back in 2020, Norwegian architecture studio Helen & Hard completed two Woodnest treehouses, a unique concept which saw the cabins anchored to living pine trees on the steep hillsides of Odda, Norway.

then a lodgepole pine—trees he expected to see at such high elevations. "Then I thought, 'What's that?'" said Safford, a forest ecologist in the UC Davis Department of Environmental Science and ...