Should tree invasions be used in treeless ecosystems to mitigate climate change?

Abstract

Intentionally allowing or promoting invasion by non-native trees into areas characterized by treeless vegetation could contribute to climate-change mitigation by increasing carbon (C) sequestration. In some areas of the world, incentives exist to retain invasive non-native trees in natural systems as a mechanism for increasing ecosystem C storage and reducing atmospheric carbon dioxide levels. Although this novel opportunity for C sequestration holds appeal, such an approach is problematic for several reasons: (1) invasive trees do not always increase net C sequestration due to greater occurrence of fire or reduced soil C; (2) lower albedo in invaded areas can increase absorption of solar radiation, thereby offsetting potential C sequestration; and (3) tree invasions often also have negative effects on biodiversity, economic opportunities, and water yield. Such drawbacks are sufficient to raise doubts about the widespread use of non-native tree invasions in treeless areas as a tool to ameliorate climate change.