A 20-year programme of research suggests that old-growth forests are ecologically unique and highly valued by people, that naturally young forests with legacies from old forests sustain many, if not all, the higher organisms associated with old growth, but that many managed forests are impoverished in species. Thus, restoring landscape function entails restoring function to managed stands. Managing processes of forest development, not just providing selected structures, is necessary to restore function and biodiversity. Systems of reserves and riparian corridors that do not take into account ecological restoration of managed forests and degraded streams may be self-fulfilling prophecies of forest fragmentation and landscape dysfunction. Intentional management can reduce the need for wide riparian buffers, produce landscapes dominated by late-seral stages that are hospitable to wildlife associated with old- growth forests, provide a sustained yield of forest products and contribute to economic, social and environmental sustainability.