Fig. 3. Silvicultural strategies to maintain or increase old-growth structures in forest
stands can rely on both retention as well as restoration to bridge or reduce the time
in stand development in which structural complexity is low or certain structural
elements may be missing, here for the example of large living trees. Continuous
black line: temporal variation of structural attribute in natural old-growth forest.
Dashed black line: loss of old-growth attribute following clearcut; dashed grey line:
delayed loss of same old-growth attribute following retention of live trees. Dashdot
line: redevelopment of old-growth attribute in regrowth forest. Grey dotted
line: accelerated redevelopment of same old-growth attribute in regrowth forest
through restoration silviculture. Note different old-growth attributes might follow
completely different patterns.