old-growth

old-growth (not comparable)

1. From, in, or pertaining to, an old-growth forest; having mature trees or other plants.
   • 2005, Sean Dooley, The Big Twitch, Sydney: Allen and Unwin, page 240:

     While on a walk the next morning I found what looked like a patch of old growth habitat - perhaps somewhere the fires had missed - and to my astonishment saw a female Red-lored Whistler accompanied by an immature.

   • 2012, John Branch, “Snow Fall : The Avalanche at Tunnel Creek”, in New York Time‎:

     Moving about 70 miles per hour, it crashed through the sturdy old-growth trees, snapping their limbs and shredding bark from their trunks.