Laurance, William FLindenmayer, David B2016-10-052016-10-050169-5347http://hdl.handle.net/1885/109160Large old trees play numerous critical ecological roles. They are susceptible to a plethora of interacting threats, in part because the attributes that confer a competitive advantage in intact ecosystems make them maladapted to rapidly changing, human-modified environments. Conserving large old trees will require surmounting a number of unresolved challenges.en-AU© Elsevier2016-0610.1016/j.tree.2016.03.003