Secondary forest regrowing after timber harvest differs from forest regrowing after natural disturbances such as fire, insect infestation, or windthrow because the dead trees remain to provide nutrients, structure, and water retention after natural disturbances.
Hardwood forests of the eastern United States, for example, can develop primary characteristics in one or two generations of trees, or 150–500 years.
[1] When forests are harvested, they either regenerate naturally or artificially (by planting and seeding select tree species).
[6] Successful recovery of biodiversity is also dependent upon local conditions, such as soil fertility, water availability, forest size, existing vegetation and seed sources, edge effect stressors, toxicity (resulting from human operations like mining), and management strategies (in assisted restoration scenarios).
[6] Low to moderate disturbances have been shown to be extremely beneficial to increase in biodiversity in secondary forests.
[4] Deforestation is one of the main causes of anthropogenic carbon dioxide emissions, making it one of the largest contributors to climate change.
[10] Recommendations from the Intergovernmental Panel on Climate Change (IPCC), Convention on Biological Diversity, and REDD+ have led to efforts to reduce and combat deforestation in places like Panama and Indonesia.
[10] Natural and human-assisted growth of secondary forests can offset carbon emissions and help countries meet climate targets.
In addition to soil nutrient levels, two areas of concern with tropical secondary forest restoration are plant biodiversity and carbon storage; it has been suggested that it takes longer for a tropical secondary forest to recover its biodiversity levels than its carbon pools.