If there’s been a central, unquestioned tenet of bird conservation in the past quarter-century, it’s been the absolute importance of large, intact tracts of mature woodland. As populations of species such as Wood Thrush, which evolved to nest deep in the interior of mature woodlands, have continued to fall for decades, the remedy for reversing those declines seemed straightforward: To save forest birds, protect and restore the unfragmented forest they need to successfully nest.
https://www.allaboutbirds.org/old-growth-is-great-but-heres-why-we-need-new-growth-forests-too/